Borrowed from cmd/compile, TestSizeof ensures
that the size of important types doesn't change unexpectedly.
It also helps reviewers see the impact of intended changes.
Change-Id: If57955f0c3e66054de3f40c6bba585b88694c7be
Reviewed-on: https://go-review.googlesource.com/99837
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
hwcap is set in archauxv, setup_auxv no longer exists.
Change-Id: I0fc9393e0c1c45192e0eff4715e9bdd69fab2653
Reviewed-on: https://go-review.googlesource.com/99779
Reviewed-by: Ian Lance Taylor <iant@golang.org>
It's a bit mysterious that _defer.sp is a uintptr that gets
stack-adjusted explicitly while _panic.argp is an unsafe.Pointer that
doesn't, but turns out to be critically important when a deferred
function grows the stack before doing a recover.
Add a comment explaining that this works because _panic values live on
the stack. Enforce this by marking _panic go:notinheap.
Change-Id: I9ca49e84ee1f86d881552c55dccd0662b530836b
Reviewed-on: https://go-review.googlesource.com/99735
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
On all non-x86 arches, runtime.abort simply reads from nil.
Unfortunately, if this happens on a user stack, the signal handler
will dutifully turn this into a panicmem, which lets user defers run
and which user code can even recover from.
To fix this, add an explicit check to the signal handler that turns
faults in abort into hard crashes directly in the signal handler. This
has the added benefit of giving a register dump at the abort point.
Change-Id: If26a7f13790745ee3867db7f53b72d8281176d70
Reviewed-on: https://go-review.googlesource.com/93661
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Everything except for amd64, amd64p32, and 386 currently defines and
uses an abort function. This CL makes these match. The next CL will
recognize the abort function to make this more useful.
Change-Id: I7c155871ea48919a9220417df0630005b444f488
Reviewed-on: https://go-review.googlesource.com/93660
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Currently, throw may grow the stack, which means whenever we call it
from a context where it's not safe to grow the stack, we first have to
switch to the system stack. This is pretty easy to get wrong.
Fix this by making throw switch to the system stack so it doesn't grow
the stack and is hence safe to call without a system stack switch at
the call site.
The only thing this complicates is badsystemstack itself, which would
now go into an infinite loop before printing anything (previously it
would also go into an infinite loop, but would at least print the
error first). Fix this by making badsystemstack do a direct write and
then crash hard.
Change-Id: Ic5b4a610df265e47962dcfa341cabac03c31c049
Reviewed-on: https://go-review.googlesource.com/93659
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Currently parts of unrecoverable panic handling (notably, printing
panic messages) can happen on the user stack. This may grow the stack,
which is generally fine, but if we're handling a runtime panic, it's
better to do as little as possible in case the runtime is in an
inconsistent state.
Hence, this commit rearranges the handling of unrecoverable panics so
that it's done entirely on the system stack.
This is mostly a matter of shuffling code a bit so everything can move
into a systemstack block. The one slight subtlety is in the "panic
during panic" case, where we now depend on startpanic_m's caller to
print the stack rather than startpanic_m itself. To make this work,
startpanic_m now returns a boolean indicating that the caller should
avoid trying to print any panic messages and get right to the stack
trace. Since the caller is already in a position to do this, this
actually simplifies things a little.
Change-Id: Id72febe8c0a9fb31d9369b600a1816d65a49bfed
Reviewed-on: https://go-review.googlesource.com/93658
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Currently if a profiling signal arrives while executing within a VDSO
the profiler will report _ExternalCode, which is needlessly confusing
for a pure Go program. Change the VDSO calling code to record the
caller's PC/SP, so that we can do a traceback from that point. If that
fails for some reason, report _VDSO rather than _ExternalCode, which
should at least point in the right direction.
This adds some instructions to the code that calls the VDSO, but the
slowdown is reasonably negligible:
name old time/op new time/op delta
ClockVDSOAndFallbackPaths/vDSO-8 40.5ns ± 2% 41.3ns ± 1% +1.85% (p=0.002 n=10+10)
ClockVDSOAndFallbackPaths/Fallback-8 41.9ns ± 1% 43.5ns ± 1% +3.84% (p=0.000 n=9+9)
TimeNow-8 41.5ns ± 3% 41.5ns ± 2% ~ (p=0.723 n=10+10)
Fixes#24142
Change-Id: Iacd935db3c4c782150b3809aaa675a71799b1c9c
Reviewed-on: https://go-review.googlesource.com/97315
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
This normalizes the Linux code to act like other targets. The size
argument to the rt_sigaction system call is pushed to a single
function, sysSigaction.
This is intended as a simplification step for CL 93875 for #14327.
Change-Id: I594788e235f0da20e16e8a028e27ac8c883907c4
Reviewed-on: https://go-review.googlesource.com/99077
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
While working on standalone builds of gomobile bindings, I ran into
errors on the form:
gcc_darwin_arm.c:30:31: error: ambiguous expansion of macro 'nil' [-Werror,-Wambiguous-macro]
/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS11.2.sdk/usr/include/MacTypes.h:94:15: note: expanding this definition of 'nil'
Fix it by undefining nil before defining it in libcgo.h.
Change-Id: I8e9660a68c6c351e592684d03d529f0d182c0493
Reviewed-on: https://go-review.googlesource.com/99215
Run-TryBot: Elias Naur <elias.naur@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
They do not match the file name patterns of
*_GOOS
*_GOARCH
*_GOOS_GOARCH
therefore the implicit linux constraint was not being added.
Change-Id: Ie506c51cee6818db445516f96fffaa351df62cf5
Reviewed-on: https://go-review.googlesource.com/99116
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Previously, for slow map key types (i.e., any type other than a 32-bit
or 64-bit plain memory type), we would rewrite
defer delete(m, k)
into
ktmp := k
defer delete(m, &ktmp)
However, if the defer statement was inside a loop, we would end up
reusing the same ktmp value for all of the deferred deletes.
We already rewrite
defer print(x, y, z)
into
defer func(a1, a2, a3) {
print(a1, a2, a3)
}(x, y, z)
This CL generalizes this rewrite to also apply for slow map deletes.
This could be extended to apply even more generally to other builtins,
but as discussed on #24259, there are cases where we must *not* do
this (e.g., "defer recover()"). However, if we elect to do this more
generally, this CL should still make that easier.
Lastly, while here, fix a few isues in wrapCall (nee walkprintfunc):
1) lookupN appends the generation number to the symbol anyway, so "%d"
was being literally included in the generated function names.
2) walkstmt will be called when the function is compiled later anyway,
so no need to do it now.
Fixes#24259.
Change-Id: I70286867c64c69c18e9552f69e3f4154a0fc8b04
Reviewed-on: https://go-review.googlesource.com/99017
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
CL 98095 got the check wrong. We should be testing
'getg() == getg().m.curg', not 'getg().m == getg().m.curg'.
Change-Id: I32f6238b00409b67afa8efe732513d542aec5bc7
Reviewed-on: https://go-review.googlesource.com/98855
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This is an updated version of golang.org/cl/96395, with the fix to
TestUserSpan.
This reverts commit 7b6f6267e90a8e4eab37a3f2164ba882e6222adb.
Change-Id: I31eec8ba0997f9178dffef8dac608e731ab70872
Reviewed-on: https://go-review.googlesource.com/98236
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
This was originally C code using names with underscores, which were
retained when the code was rewritten into Go. Change the code to use
Go-like camel case names.
The names that come from the ELF ABI are left unchanged.
Change-Id: I181bc5dd81284c07bc67b7df4635f4734b41d646
Reviewed-on: https://go-review.googlesource.com/98520
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Also fix the indentation of the SYS_* definitions in sys_linux_mipsx.s
and order them numerically.
Change-Id: I0c454301c329a163e7db09dcb25d4e825149858c
Reviewed-on: https://go-review.googlesource.com/98448
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Use the __vdso_clock_gettime fast path via the vDSO on linux/arm to
speed up nanotime and walltime. This results in the following
performance improvement for time.Now on a RaspberryPi 3 (running
32bit Raspbian, i.e. GOOS=linux/GOARCH=arm):
name old time/op new time/op delta
TimeNow 0.99µs ± 0% 0.39µs ± 1% -60.74% (p=0.000 n=12+20)
Change-Id: I3598278a6c88d7f6a6ce66c56b9d25f9dd2f4c9a
Reviewed-on: https://go-review.googlesource.com/98095
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Move the IndexByte function from the runtime to a new bytealg package.
The new package will eventually hold all the optimized assembly for
groveling through byte slices and strings. It seems a better home for
this code than randomly keeping it in runtime.
Once this is in, the next step is to move the other functions
(Compare, Equal, ...).
Update #19792
This change seems complicated enough that we might just declare
"not worth it" and abandon. Opinions welcome.
The core assembly is all unchanged, except minor modifications where
the code reads cpu feature bits.
The wrapper functions have been cleaned up as they are now actually
checked by vet.
Change-Id: I9fa75bee5d85db3a65b3fd3b7997e60367523796
Reviewed-on: https://go-review.googlesource.com/98016
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This reverts commit 7365fac2db.
Reason for revert: breaks the build on some architectures, reading unmapped pages?
Change-Id: I3a8c02dc0b649269faacea79ecd8213defa97c54
Reviewed-on: https://go-review.googlesource.com/97995
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
bytes.IndexByte is heavily optimized.
Use it in findnull.
name old time/op new time/op delta
GoString-8 65.5ns ± 1% 40.2ns ± 1% -38.62% (p=0.000 n=19+19)
findnull is also used in gostringnocopy,
which is used in many hot spots in the runtime.
Fixes#23830
Change-Id: I2e6cb279c7d8078f8844065de684cc3567fe89d7
Reviewed-on: https://go-review.googlesource.com/97523
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Change-Id: I030baaa0a0abf1e43449faaf676d389a28a868a3
Reviewed-on: https://go-review.googlesource.com/97857
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
Reviewed-by: Peter Weinberger <pjw@google.com>
When the slice/string length is very large,
probably artifically large as in CL 97523,
adding BX (length) to R11 (pointer) overflows.
As a result, checking DI < R11 yields the wrong result.
Since they will be equal when the loop is done,
just check DI != R11 instead.
Yes, the pointer itself could overflow, but if that happens,
something else has gone pretty wrong; not our concern here.
Fixes#24187
Change-Id: I2f60fc6ccae739345d01bc80528560726ad4f8c6
Reviewed-on: https://go-review.googlesource.com/97802
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
All functions defined in syscall2_solaris.go have the respective libc_*
var in syscall_solaris.go, except for libc_close. Move it from
os3_solaris.go
Remove unused libc_fstat.
Order go:cgo_import_dynamic and go:linkname lists in
syscall2_solaris.go alphabetically.
Change-Id: I9f12fa473cf1ae351448ac45597c82a67d799c31
Reviewed-on: https://go-review.googlesource.com/97736
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Plan 9 won't let brk shrink the data segment if it's shared with
other processes (which it is in the go runtime). So we keep track
of the notional end of the segment as it moves up and down, and
call brk only when it grows.
Corrects CL 94776.
Updates #23860.
Fixes#24013.
Change-Id: I754232decab81dfd71d690f77ee6097a17d9be11
Reviewed-on: https://go-review.googlesource.com/97595
Reviewed-by: David du Colombier <0intro@gmail.com>
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: David du Colombier <0intro@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The first word of an interface is a pointer, but for the purposes
of GC we don't need to treat it as such.
1. If it is a non-empty interface, the pointer points to an itab
which is always in persistentalloc space.
2. If it is an empty interface, the pointer points to a _type.
a. If it is a compile-time-allocated type, it points into
the read-only data section.
b. If it is a reflect-allocated type, it points into the Go heap.
Reflect is responsible for keeping a reference to
the underlying type so it won't be GCd.
If we ever have a moving GC, we need to change this for 2b (as
well as scan itabs to update their itab._type fields).
Write barriers on the first word of interfaces have already been removed.
Change-Id: I643e91d7ac4de980ac2717436eff94097c65d959
Reviewed-on: https://go-review.googlesource.com/97518
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Minor improvements, noticed while investigating other things.
Shorten the prologue.
Make branch direction better for static branch prediction;
the most common case by far is switching stacks (g==curg).
Change-Id: Ib2211d3efecb60446355cda56194221ccb78057d
Reviewed-on: https://go-review.googlesource.com/97377
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
They have either already been called by preprintpanics, or they can
not be called safely because of the various conditions checked at the
start of gopanic.
Fixes#24059
Change-Id: I4a6233d12c9f7aaaee72f343257ea108bae79241
Reviewed-on: https://go-review.googlesource.com/96755
Reviewed-by: Austin Clements <austin@google.com>
Currently, we use 64MB heap arenas on 64-bit platforms. This works
well on UNIX-like OSes because they treat untouched pages as
essentially free. However, on Windows, committed memory is charged
against a process whether or not it has demand-faulted physical pages
in. Hence, on Windows, even a process with a tiny heap will commit
64MB for one heap arena, plus another 32MB for the arena map. Things
are much worse under the race detector, which increases the heap
commitment by a factor of 5.5X, leading to 384MB of committed memory
at runtime init.
Fix this by reducing the heap arena size to 4MB on Windows.
To counterbalance the effect of increasing the arena map size by a
factor of 16, and to further reduce the impact of the commitment for
the arena map, we switch from a single entry L1 arena map to a 64
entry L1 arena map.
Compared to the original arena design, this slows down the
x/benchmarks garbage benchmark by 0.49% (the slow down of this commit
alone is 1.59%, but the previous commit bought us a 1% speed-up):
name old time/op new time/op delta
Garbage/benchmem-MB=64-12 2.28ms ± 1% 2.29ms ± 1% +0.49% (p=0.000 n=17+18)
(https://perf.golang.org/search?q=upload:20180223.1)
(This was measured on linux/amd64 by modifying its arena configuration
as above.)
Fixes#23900.
Change-Id: I6b7fa5ecebee2947bf20cfeb78c248809469c6b1
Reviewed-on: https://go-review.googlesource.com/96780
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
Currently, the heap arena map is a single, large array that covers
every possible arena frame in the entire address space. This is
practical up to about 48 bits of address space with 64 MB arenas.
However, there are two problems with this:
1. mips64, ppc64, and s390x support full 64-bit address spaces (though
on Linux only s390x has kernel support for 64-bit address spaces).
On these platforms, it would be good to support these larger
address spaces.
2. On Windows, processes are charged for untouched memory, so for
processes with small heaps, the mostly-untouched 32 MB arena map
plus a 64 MB arena are significant overhead. Hence, it would be
good to reduce both the arena map size and the arena size, but with
a single-level arena, these are inversely proportional.
This CL adds support for a two-level arena map. Arena frame numbers
are now divided into arenaL1Bits of L1 index and arenaL2Bits of L2
index.
At the moment, arenaL1Bits is always 0, so we effectively have a
single level map. We do a few things so that this has no cost beyond
the current single-level map:
1. We embed the L2 array directly in mheap, so if there's a single
entry in the L2 array, the representation is identical to the
current representation and there's no extra level of indirection.
2. Hot code that accesses the arena map is structured so that it
optimizes to nearly the same machine code as it does currently.
3. We make some small tweaks to hot code paths and to the inliner
itself to keep some important functions inlined despite their
now-larger ASTs. In particular, this is necessary for
heapBitsForAddr and heapBits.next.
Possibly as a result of some of the tweaks, this actually slightly
improves the performance of the x/benchmarks garbage benchmark:
name old time/op new time/op delta
Garbage/benchmem-MB=64-12 2.28ms ± 1% 2.26ms ± 1% -1.07% (p=0.000 n=17+19)
(https://perf.golang.org/search?q=upload:20180223.2)
For #23900.
Change-Id: If5164e0961754f97eb9eca58f837f36d759505ff
Reviewed-on: https://go-review.googlesource.com/96779
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
There are too many places where I want to talk about "indexing into
the arena index". Make this less awkward and ambiguous by calling it
the "arena map" instead.
Change-Id: I726b0667bb2139dbc006175a0ec09a871cdf73f9
Reviewed-on: https://go-review.googlesource.com/96777
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Rick Hudson <rlh@golang.org>
On amd64, the arena is no longer in address space order, but currently
the heap dumper assumes that it is. Fix this assumption.
Change-Id: Iab1953cd36b359d0fb78ed49e5eb813116a18855
Reviewed-on: https://go-review.googlesource.com/96776
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
There was still the word 'Hashmap' in gc_test.go, so I renamed it to just 'Map'
Previous renaming commit: https://golang.org/cl/90336
Change-Id: I5b0e5c2229d1c30937c7216247f4533effb81ce7
Reviewed-on: https://go-review.googlesource.com/96675
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Now that we support the full non-contiguous virtual address space of
amd64 hardware, some of the comments and constants related to this are
out of date.
This renames memLimitBits to heapAddrBits because 1<<memLimitBits is
no longer the limit of the address space and rewrites the comment to
focus first on hardware limits (which span OSes) and then discuss
kernel limits.
Second, this eliminates the memLimit constant because there's no
longer a meaningful "highest possible heap pointer value" on amd64.
Updates #23862.
Change-Id: I44b32033d2deb6b69248fb8dda14fc0e65c47f11
Reviewed-on: https://go-review.googlesource.com/95498
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
On amd64, the virtual address space, when interpreted as signed
values, is [-2^47, 2^47). Currently, we only support heap addresses in
the "positive" half of this, [0, 2^47). This suffices for linux/amd64
and windows/amd64, but solaris/amd64 can map user addresses in the
negative part of this range. Specifically, addresses
0xFFFF8000'00000000 to 0xFFFFFD80'00000000 are part of user space.
This leads to "memory allocated by OS not in usable address space"
panic, since we don't map heap arena index space for these addresses.
Fix this by offsetting addresses when computing arena indexes so that
arena entry 0 corresponds to address -2^47 on amd64. We already map
enough arena space for 2^48 heap addresses on 64-bit (because arm64's
virtual address space is [0, 2^48)), so we don't need to grow any
structures to support this.
A different approach would be to simply mask out the top 16 bits.
However, there are two advantages to the offset approach: 1) invalid
heap addresses continue to naturally map to invalid arena indexes so
we don't need extra checks and 2) it perturbs the mapping of addresses
to arena indexes more, which helps check that we don't accidentally
compute incorrect arena indexes somewhere that happen to be right most
of the time.
Several comments and constant names are now somewhat misleading. We'll
fix that in the next CL. This CL is the core change the arena
indexing.
Fixes#23862.
Change-Id: Idb8e299fded04593a286b01a9582da6ddbac2f9a
Reviewed-on: https://go-review.googlesource.com/95497
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
Accessing the arena index is about to get slightly more complicated.
Abstract this away into a set of functions for going back and forth
between addresses and arena slice indexes.
For #23862.
Change-Id: I0b20e74ef47a07b78ed0cf0a6128afe6f6e40f4b
Reviewed-on: https://go-review.googlesource.com/95496
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
Currently, bulkBarrierPreWrite uses inheap to decide whether the
destination is in the heap or whether to check for stack or global
data. However, this isn't the best question to ask.
Instead, get the span directly and query its state. This lets us
directly determine whether this might be a global, or is stack memory,
or is heap memory.
At this point, inheap is no longer used in the hot path, so drop it
from the must-be-inlined list and substitute spanOf.
This will help in a circuitous way with #23862, since fixing that is
going to push inheap very slightly over the inline-able threshold on a
few platforms.
Change-Id: I5360fc1181183598502409f12979899e1e4d45f7
Reviewed-on: https://go-review.googlesource.com/95495
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
We don't want to account the memory for mheap_.arenas because most of
it is never touched, so currently we pass the address of a uint64 on
the heap. However, at least on mips, it's possible for this uint64 to
be unaligned, which causes the atomic add in mSysStatInc to crash.
Fix this by instead passing a nil stat pointer.
Fixes#23946.
Change-Id: I091587df1b3066c330b6bb4d834e4596c407910f
Reviewed-on: https://go-review.googlesource.com/95695
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
reflect.unsafe_New is an often called function according
to profiling in a large production environment.
Since newobject is not inlined currently there
is call overhead that can be avoided by calling
mallocgc directly.
name old time/op new time/op delta
New 32.4ns ± 2% 29.8ns ± 1% -8.03% (p=0.000 n=19+20)
Change-Id: I572e4be830ed8e5c0da555dc3a8864c8363112be
Reviewed-on: https://go-review.googlesource.com/95015
Reviewed-by: Austin Clements <austin@google.com>
Avoid using make in gobytes which clears the byte slice backing
array unnecessarily since the content is overwritten immediately again.
Check that the user provided length is positive and below the maximum
allowed allocation size explicitly in gobytes as this was done in makeslice
before this change.
Fixes#23634
Change-Id: Id852619e932aabfc468871c42ad07d34da91f45c
Reviewed-on: https://go-review.googlesource.com/94760
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Follow CL 93655 which removed the (commented-out) usage of this
function.
Also remove unused constant _RLIMIT_AS and type rlimit.
Change-Id: Ifb6e6b2104f4c2555269f8ced72bfcae24f5d5e9
Reviewed-on: https://go-review.googlesource.com/94775
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Overall code is unchanged.
The functions for different types (32, 64, str) of map fast routines
are collected in map_fast.go that has grown to ~1300 lines.
Moving the functions for each map fast type into a separate file
allows for an easier overview and navigation within the map code.
Change-Id: Ic09e4212f9025a66a10b11ef8dac23ad49d1d5ae
Reviewed-on: https://go-review.googlesource.com/90335
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Rename all map implementation and test files to use "map"
as a file name prefix instead of "hashmap" for the implementation
and "map" for the test file names.
Change-Id: I7b317c1f7a660b95c6d1f1a185866f2839e69446
Reviewed-on: https://go-review.googlesource.com/90336
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
On Plan 9, sysReserve was ignoring the address hint and allocating
memory wherever it is available. This causes the new
TestArenaCollision test to fail on 32-bit Plan 9. We now use the
address hint in the specific case where sysReserve is extending the
process address space at its end, and similarly we contract the
address space in the case where sysFree is releasing memory at
the end.
Fixes#23860
Change-Id: Ia5254779ba8f1698c999832720a88de400b5f91a
Reviewed-on: https://go-review.googlesource.com/94776
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: David du Colombier <0intro@gmail.com>
Replace the test for nacl with testenv.MustHaveExec to also skip
test on iOS.
Change-Id: I6822714f6d71533d1b18bbb7894f6ad339d8aea1
Reviewed-on: https://go-review.googlesource.com/94755
Run-TryBot: Elias Naur <elias.naur@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Now that we have memLimit, also having _MaxMem is a bit confusing.
Replace it with maxAlloc, which better conveys what it limits. We also
define maxAlloc slightly differently: since it's now clear that it
limits allocation size, we can account for a subtle difference between
32-bit and 64-bit.
Change-Id: Iac39048018cc0dae7f0919e25185fee4b3eed529
Reviewed-on: https://go-review.googlesource.com/85890
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
Currently there's a detailed comment in lfstack_64bit.go about address
space limitations on various architectures. Since that's now relevant
to malloc, move it to a more prominent place in the documentation for
memLimitBits.
Updates #10460.
Change-Id: If9708291cf3a288057b8b3ba0ba6a59e3602bbd6
Reviewed-on: https://go-review.googlesource.com/85889
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
Currently large sysReserve calls on some OSes don't actually reserve
the memory, but just check that it can be reserved. This was important
when we called sysReserve to "reserve" many gigabytes for the heap up
front, but now that we map memory in small increments as we need it,
this complication is no longer necessary.
This has one curious side benefit: currently, on Linux, allocations
that are large enough to be rejected by mmap wind up freezing the
application for a long time before it panics. This happens because
sysReserve doesn't reserve the memory, so sysMap calls mmap_fixed,
which calls mmap, which fails because the mapping is too large.
However, mmap_fixed doesn't inspect *why* mmap fails, so it falls back
to probing every page in the desired region individually with mincore
before performing an (otherwise dangerous) MAP_FIXED mapping, which
will also fail. This takes a long time for a large region. Now this
logic is gone, so the mmap failure leads to an immediate panic.
Updates #10460.
Change-Id: I8efe88c611871cdb14f99fadd09db83e0161ca2e
Reviewed-on: https://go-review.googlesource.com/85888
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
This replaces the contiguous heap arena mapping with a potentially
sparse mapping that can support heap mappings anywhere in the address
space.
This has several advantages over the current approach:
* There is no longer any limit on the size of the Go heap. (Currently
it's limited to 512GB.) Hence, this fixes#10460.
* It eliminates many failures modes of heap initialization and
growing. In particular it eliminates any possibility of panicking
with an address space conflict. This can happen for many reasons and
even causes a low but steady rate of TSAN test failures because of
conflicts with the TSAN runtime. See #16936 and #11993.
* It eliminates the notion of "non-reserved" heap, which was added
because creating huge address space reservations (particularly on
64-bit) led to huge process VSIZE. This was at best confusing and at
worst conflicted badly with ulimit -v. However, the non-reserved
heap logic is complicated, can race with other mappings in non-pure
Go binaries (e.g., #18976), and requires that the entire heap be
either reserved or non-reserved. We currently maintain the latter
property, but it's quite difficult to convince yourself of that, and
hence difficult to keep correct. This logic is still present, but
will be removed in the next CL.
* It fixes problems on 32-bit where skipping over parts of the address
space leads to mapping huge (and never-to-be-used) metadata
structures. See #19831.
This also completely rewrites and significantly simplifies
mheap.sysAlloc, which has been a source of many bugs. E.g., #21044,
#20259, #18651, and #13143 (and maybe #23222).
This change also makes it possible to allocate individual objects
larger than 512GB. As a result, a few tests that expected huge
allocations to fail needed to be changed to make even larger
allocations. However, at the moment attempting to allocate a humongous
object may cause the program to freeze for several minutes on Linux as
we fall back to probing every page with addrspace_free. That logic
(and this failure mode) will be removed in the next CL.
Fixes#10460.
Fixes#22204 (since it rewrites the code involved).
This slightly slows down compilebench and the x/benchmarks garbage
benchmark.
name old time/op new time/op delta
Template 184ms ± 1% 185ms ± 1% ~ (p=0.065 n=10+9)
Unicode 86.9ms ± 3% 86.3ms ± 1% ~ (p=0.631 n=10+10)
GoTypes 599ms ± 0% 602ms ± 0% +0.56% (p=0.000 n=10+9)
Compiler 2.87s ± 1% 2.89s ± 1% +0.51% (p=0.002 n=9+10)
SSA 7.29s ± 1% 7.25s ± 1% ~ (p=0.182 n=10+9)
Flate 118ms ± 2% 118ms ± 1% ~ (p=0.113 n=9+9)
GoParser 147ms ± 1% 148ms ± 1% +1.07% (p=0.003 n=9+10)
Reflect 401ms ± 1% 404ms ± 1% +0.71% (p=0.003 n=10+9)
Tar 175ms ± 1% 175ms ± 1% ~ (p=0.604 n=9+10)
XML 209ms ± 1% 210ms ± 1% ~ (p=0.052 n=10+10)
(https://perf.golang.org/search?q=upload:20171231.4)
name old time/op new time/op delta
Garbage/benchmem-MB=64-12 2.23ms ± 1% 2.25ms ± 1% +0.84% (p=0.000 n=19+19)
(https://perf.golang.org/search?q=upload:20171231.3)
Relative to the start of the sparse heap changes (starting at and
including "runtime: fix various contiguous bitmap assumptions"),
overall slowdown is roughly 1% on GC-intensive benchmarks:
name old time/op new time/op delta
Template 183ms ± 1% 185ms ± 1% +1.32% (p=0.000 n=9+9)
Unicode 84.9ms ± 2% 86.3ms ± 1% +1.65% (p=0.000 n=9+10)
GoTypes 595ms ± 1% 602ms ± 0% +1.19% (p=0.000 n=9+9)
Compiler 2.86s ± 0% 2.89s ± 1% +0.91% (p=0.000 n=9+10)
SSA 7.19s ± 0% 7.25s ± 1% +0.75% (p=0.000 n=8+9)
Flate 117ms ± 1% 118ms ± 1% +1.10% (p=0.000 n=10+9)
GoParser 146ms ± 2% 148ms ± 1% +1.48% (p=0.002 n=10+10)
Reflect 398ms ± 1% 404ms ± 1% +1.51% (p=0.000 n=10+9)
Tar 173ms ± 1% 175ms ± 1% +1.17% (p=0.000 n=10+10)
XML 208ms ± 1% 210ms ± 1% +0.62% (p=0.011 n=10+10)
[Geo mean] 369ms 373ms +1.17%
(https://perf.golang.org/search?q=upload:20180101.2)
name old time/op new time/op delta
Garbage/benchmem-MB=64-12 2.22ms ± 1% 2.25ms ± 1% +1.51% (p=0.000 n=20+19)
(https://perf.golang.org/search?q=upload:20180101.3)
Change-Id: I5daf4cfec24b252e5a57001f0a6c03f22479d0f0
Reviewed-on: https://go-review.googlesource.com/85887
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
This replaces all uses of the mheap_.arena_* fields outside of
mallocinit and sysAlloc. These fields fundamentally assume a
contiguous heap between two bounds, so eliminating these is necessary
for a sparse heap.
Many of these are replaced with checks for non-nil spans at the test
address (which in turn checks for a non-nil entry in the heap arena
array). Some of them are just for debugging and somewhat meaningless
with a sparse heap, so those we just delete.
Updates #10460.
Change-Id: I8345b95ffc610aed694f08f74633b3c63506a41f
Reviewed-on: https://go-review.googlesource.com/85886
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
This abstracts the remaining direct accesses to mheap.spans into new
mheap.setSpan and mheap.setSpans methods.
For #10460.
Change-Id: Id1db8bc5e34a77a9221032aa2e62d05322707364
Reviewed-on: https://go-review.googlesource.com/85884
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
This splits the heap bitmap into separate chunks for every 64MB of the
heap and introduces an index mapping from virtual address to metadata.
It modifies the heapBits abstraction to use this two-level structure.
Finally, it modifies heapBitsSetType to unroll the bitmap into the
object itself and then copy it out if the bitmap would span
discontiguous bitmap chunks.
This is a step toward supporting general sparse heaps, which will
eliminate address space conflict failures as well as the limit on the
heap size.
It's also advantageous for 32-bit. 32-bit already supports
discontiguous heaps by always starting the arena at address 0.
However, as a result, with a contiguous bitmap, if the kernel chooses
a high address (near 2GB) for a heap mapping, the runtime is forced to
map up to 128MB of heap bitmap. Now the runtime can map sections of
the bitmap for just the parts of the address space used by the heap.
Updates #10460.
This slightly slows down the x/garbage and compilebench benchmarks.
However, I think the slowdown is acceptably small.
name old time/op new time/op delta
Template 178ms ± 1% 180ms ± 1% +0.78% (p=0.029 n=10+10)
Unicode 85.7ms ± 2% 86.5ms ± 2% ~ (p=0.089 n=10+10)
GoTypes 594ms ± 0% 599ms ± 1% +0.70% (p=0.000 n=9+9)
Compiler 2.86s ± 0% 2.87s ± 0% +0.40% (p=0.001 n=9+9)
SSA 7.23s ± 2% 7.29s ± 2% +0.94% (p=0.029 n=10+10)
Flate 116ms ± 1% 117ms ± 1% +0.99% (p=0.000 n=9+9)
GoParser 146ms ± 1% 146ms ± 0% ~ (p=0.193 n=10+7)
Reflect 399ms ± 0% 403ms ± 1% +0.89% (p=0.001 n=10+10)
Tar 173ms ± 1% 174ms ± 1% +0.91% (p=0.013 n=10+9)
XML 208ms ± 1% 210ms ± 1% +0.93% (p=0.000 n=10+10)
[Geo mean] 368ms 371ms +0.79%
name old time/op new time/op delta
Garbage/benchmem-MB=64-12 2.17ms ± 1% 2.21ms ± 1% +2.15% (p=0.000 n=20+20)
Change-Id: I037fd283221976f4f61249119d6b97b100bcbc66
Reviewed-on: https://go-review.googlesource.com/85883
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
There are various places that assume the heap bitmap is contiguous and
scan it sequentially. We're about to split up the heap bitmap. This
commit modifies all of these except heapBitsSetType to use the
heapBits abstractions so they can transparently switch to a
discontiguous bitmap.
Updates #10460. This is a step toward supporting sparse heaps.
Change-Id: I2f3994a5785e4dccb66602fb3950bbd290d9392c
Reviewed-on: https://go-review.googlesource.com/85882
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
Currently the heap bitamp is laid in reverse order in memory relative
to the heap itself. This was originally done out of "excessive
cleverness" so that computing a bitmap pointer could load only the
arena_start field and so that heaps could be more contiguous by
growing the arena and the bitmap out from a common center point.
However, this appears to have no actual performance benefit, it
complicates nearly every use of the bitmap, and it makes already
confusing code more confusing. Furthermore, it's still possible to use
a single field (the new bitmap_delta) for the bitmap pointer
computation by employing slightly different excessive cleverness.
Hence, this CL puts the bitmap into forward order.
This is a (very) updated version of CL 9404.
Change-Id: I743587cc626c4ecd81e660658bad85b54584108c
Reviewed-on: https://go-review.googlesource.com/85881
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
The logic in the spanOf* functions is open-coded in a lot of places
right now. Replace these with calls to the spanOf* functions.
Change-Id: I3cc996aceb9a529b60fea7ec6fef22008c012978
Reviewed-on: https://go-review.googlesource.com/85880
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
I think we'd forgotten about the mheap.lookup APIs when we introduced
spanOf*, but, at any rate, the spanOf* functions are used far more
widely at this point, so this CL eliminates the mheap.lookup*
functions in favor of spanOf*.
Change-Id: I15facd0856e238bb75d990e838a092b5bef5bdfc
Reviewed-on: https://go-review.googlesource.com/85879
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
heapBitsForObject does two things: it finds the base of the object and
it creates the heapBits for the base of the object. There are several
places where we just care about the base of the object. Furthermore,
greyobject only needs the heapBits in the checkmark path and can
easily compute them only when needed. Once we eliminate passing the
heap bits to grayobject, almost all uses of heapBitsForObject don't
need the heap bits.
Hence, this splits heapBitsForObject into findObject and
heapBitsForAddr (the latter already exists), removes the hbits
argument to grayobject, and replaces all heapBitsForObject calls with
calls to findObject.
In addition to making things cleaner overall, heapBitsForAddr is going
to get more expensive shortly, so it's important that we don't do it
needlessly.
Note that there's an interesting performance pitfall here. I had
originally moved findObject to mheap.go, since it made more sense
there. However, that leads to a ~2% slow down and a whopping 11%
increase in L1 icache misses on both the x/garbage and compilebench
benchmarks. This suggests we may want to be more principled about
this, but, for now, let's just leave findObject in mbitmap.go.
(I tried to make findObject small enough to inline by splitting out
the error case, but, sadly, wasn't quite able to get it under the
inlining budget.)
Change-Id: I7bcb92f383ade565d22a9f2494e4c66fd513fb10
Reviewed-on: https://go-review.googlesource.com/85878
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
These functions all serve essentially the same purpose. mlookup is
used in only one place and findObject in only three. Use
heapBitsForObject instead, which is the most optimized implementation.
(This may seem slightly silly because none of these uses care about
the heap bits, but we're about to split up the functionality of
heapBitsForObject anyway. At that point, findObject will rise from the
ashes.)
Change-Id: I906468c972be095dd23cf2404a7d4434e802f250
Reviewed-on: https://go-review.googlesource.com/85877
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
I was spelunking Linux's address space code and found that some of the
information about maximum virtual addresses in lfstack's comments was
out of date. This expands and updates the comment.
Change-Id: I9f54b23e6b266b3c5cc20259a849231fb751f6e7
Reviewed-on: https://go-review.googlesource.com/85875
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
Also add testdata for version 1.11 including UserTaskSpan test trace.
Change-Id: I673fb29bb3aee96a14fadc0ab860d4f5832143f5
Reviewed-on: https://go-review.googlesource.com/93795
Reviewed-by: Heschi Kreinick <heschi@google.com>
This implements the annotation API proposed in golang.org/cl/63274.
traceString is updated to protect the string map with trace.stringsLock
because the assumption that traceString is called by a single goroutine
(either at the beginning of tracing and at the end of tracing when
dumping all the symbols and function names) is no longer true.
traceString is used by the annotation apis (NewContext, StartSpan, Log)
to register frequently appearing strings (task and span names, and log
keys) after this change.
NewContext -> one or two records (EvString, EvUserTaskCreate)
end function -> one record (EvUserTaskEnd)
StartSpan -> one or two records (EvString, EvUserSpan)
span end function -> one or two records (EvString, EvUserSpan)
Log -> one or two records (EvString, EvUserLog)
EvUserLog record is of the typical record format written by traceEvent
except that it is followed by bytes that represents the value string.
In addition to runtime/trace change, this change includes
corresponding changes in internal/trace to parse the new record types.
Future work to improve efficiency:
More efficient unique task id generation instead of atomic. (per-P
counter).
Instead of a centralized trace.stringsLock, consider using per-P
string cache or something more efficient.
R=go1.11
Change-Id: Iec9276c6c51e5be441ccd52dec270f1e3b153970
Reviewed-on: https://go-review.googlesource.com/71690
Reviewed-by: Austin Clements <austin@google.com>
This CL presents the proposed user annotation API skeleton.
This CL bumps up the trace version to 1.11.
Design doc https://goo.gl/iqJfJ3
Implementation CLs are followed.
The API introduces three basic building blocks. Log, Span, and Task.
Log is for basic logging. When called, the message will be recorded
to the trace along with timestamp, goroutine id, and stack info.
trace.Log(ctx, messageType message)
Span can be thought as an extension of log to record interesting
time interval during a goroutine's execution. A span is local to a
goroutine by definition.
trace.WithSpan(ctx, "doVeryExpensiveOp", func(ctx context) {
/* do something very expensive */
})
Task is higher-level concept that aids tracing of complex operations
that encompass multiple goroutines or are asynchronous.
For example, an RPC request, a HTTP request, a file write, or a
batch job can be traced with a Task.
Note we chose to design the API around context.Context so it allows
easier integration with other tracing tools, often designed around
context.Context as well. Log and WithSpan APIs recognize the task
information embedded in the context and record it in the trace as
well. That allows the Go execution tracer to associate and group
the spans and log messages based on the task information.
In order to create a Task,
ctx, end := trace.NewContext(ctx, "myTask")
defer end()
The Go execution tracer measures the time between the task created
and the task ended for the task latency.
More discussion history in golang.org/cl/59572.
Update #16619
R=go1.11
Change-Id: I59a937048294dafd23a75cf1723c6db461b193cd
Reviewed-on: https://go-review.googlesource.com/63274
Reviewed-by: Austin Clements <austin@google.com>
Move the ELF32 and ELF64 structure definitions into their own files so
they can be reused when vDSO support is added for other architectures.
Change-Id: Id0171b4e5cea4add8635743c881e3bf3469597af
Reviewed-on: https://go-review.googlesource.com/93995
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
If copying from a slice to itself, skip the write barriers
and actual memory copies.
This happens in practice in code like this snippet from
the trim pass in the compiler, when k ends up being 0:
copy(s.Values[k:], s.Values[:m])
Change-Id: Ie6924acfd56151f874d87f1d7f1f74320b4c4f10
Reviewed-on: https://go-review.googlesource.com/94023
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
The runtime.hmap type is known at compile time.
Using new(hmap) avoids loading the hmap type from the maptype
supplied as an argument to makemap which is only known at runtime.
This change makes makemap consistent with makemap_small
by using new(hmap) instead of newobject in both functions.
Change-Id: Ia47acfda527e8a71d15a1a7a4c2b54fb923515eb
Reviewed-on: https://go-review.googlesource.com/91775
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
The runtime builtin functions that are tested in append_test.go
are defined in slice.go. Renaming the test file to slice_test.go
makes this relation explicit with a common file name prefix.
Change-Id: I2f89ec23a6077fe6b80d2161efc760df828c8cd4
Reviewed-on: https://go-review.googlesource.com/90655
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
By default futexes are permitted in shared memory regions, which
requires the kernel to translate the memory address. Since our futexes
are never in shared memory, set FUTEX_PRIVATE_FLAG, which makes futex
operations slightly more efficient.
Change-Id: I2a82365ed27d5cd8d53c5382ebaca1a720a80952
Reviewed-on: https://go-review.googlesource.com/80144
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
On nacl/arm, R12 is clobbered by the RET instruction in function
that has a frame. runtime.udiv doesn't have a frame, so it does
not clobber R12.
Change-Id: I0de448749f615908f6659e92d201ba3eb2f8266d
Reviewed-on: https://go-review.googlesource.com/93116
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
The stackguard is set to stackPreempt earlier in reentersyscall, and
as it comes with throwsplit = true there's no way for the stackguard
to be set to anything else by the end of reentersyscall.
Change-Id: I4e942005b22ac784c52398c74093ac887fc8ec24
Reviewed-on: https://go-review.googlesource.com/65673
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Also order the syscall number list by numerically for mips64x.
Follow-up for CL 92895.
Change-Id: I5f01f8c626132a06160997fce8a2aef0c486bb1c
Reviewed-on: https://go-review.googlesource.com/93616
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
CL 92916 added the GOMAXPROCS test in TestTraceSymbolize.
This test only succeeds when the value of GOMAXPROCS changes.
Since the test calls runtime.GOMAXPROCS(1), it will fails
on machines where GOMAXPROCS=1.
This change fixes the test by calling runtime.GOMAXPROCS(oldGoMaxProcs+1).
Fixes#23816.
Change-Id: I1183dbbd7db6077cbd7fa0754032ff32793b2195
Reviewed-on: https://go-review.googlesource.com/93735
Run-TryBot: David du Colombier <0intro@gmail.com>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Currently, if a sigpanic call is injected into C code, it's possible
for preparePanic to leave the stack in a state where traceback can't
unwind correctly past the sigpanic.
Specifically, shouldPushPanic sniffs the stack to decide where to put
the PC from the signal context. In the cgo case, it will find that
!findfunc(pc).valid() because pc is in C code, and then it will check
if the top of the stack looks like a Go PC. However, this stack slot
is just in a C frame, so it could be uninitialized and contain
anything, including what looks like a valid Go PC. For example, in
https://build.golang.org/log/c601a18e2af24794e6c0899e05dddbb08caefc17,
it sees 1c02c23a <runtime.newproc1+682>. When this condition is met,
it skips putting the signal PC on the stack at all. As a result, when
we later unwind from the sigpanic, we'll "successfully" but
incorrectly unwind to whatever PC was in this uninitialized slot and
go who knows where from there.
Fix this by making shouldPushPanic assume that the signal PC is always
usable if we're running C code, so we always make it appear like
sigpanic's caller.
This lets us be pickier again about unexpected return PCs in
gentraceback.
Updates #23640.
Change-Id: I1e8ade24b031bd905d48e92d5e60c982e8edf160
Reviewed-on: https://go-review.googlesource.com/91137
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This logic is duplicated in all of the preparePanic functions. Pull it
out into one architecture-independent function.
Change-Id: I7ef4e78e3eda0b7be1a480fb5245fc7424fb2b4e
Reviewed-on: https://go-review.googlesource.com/91255
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Previously find_goroutine determined whether a goroutine is
stopped by checking the sched.sp field. This heuristic doesn't
always hold but causes find_goroutine to return bogus pc/sp
info for running goroutines.
This change uses the atomicstatus bit to determine
the state which is more accurate.
R=go1.11
Change-Id: I537d432d9e0363257120a196ce2ba52da2970f59
Reviewed-on: https://go-review.googlesource.com/49691
Reviewed-by: Austin Clements <austin@google.com>
Instead evaluate and read the runtime internal constants
defined in runtime2.go
R=go1.11
Change-Id: If2f4b87e5b3f62f0c0ff1e86a90db8e37a78abb6
Reviewed-on: https://go-review.googlesource.com/87877
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
Reviewed-by: Austin Clements <austin@google.com>
and reorganize test log messages for stack dumps
for easier debugging.
The error log will be formatted like the following:
trace_stack_test.go:282: Did not match event GoCreate with stack
runtime/trace_test.TestTraceSymbolize :39
testing.tRunner :0
Seen 30 events of the type
Offset 1890
runtime/trace_test.TestTraceSymbolize /go/src/runtime/trace/trace_stack_test.go:30
testing.tRunner /go/src/testing/testing.go:777
Offset 1899
runtime/trace_test.TestTraceSymbolize /go/src/runtime/trace/trace_stack_test.go:30
testing.tRunner /go/src/testing/testing.go:777
...
Change-Id: I0468de04507d6ae38ba84d99d13f7bf592e8d115
Reviewed-on: https://go-review.googlesource.com/92916
Reviewed-by: Heschi Kreinick <heschi@google.com>
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
Now that the buffered write barrier is implemented for all
architectures, we can remove the old eager write barrier
implementation. This CL removes the implementation from the runtime,
support in the compiler for calling it, and updates some compiler
tests that relied on the old eager barrier support. It also makes sure
that all of the useful comments from the old write barrier
implementation still have a place to live.
Fixes#22460.
Updates #21640 since this fixes the layering concerns of the write
barrier (but not the other things in that issue).
Change-Id: I580f93c152e89607e0a72fe43370237ba97bae74
Reviewed-on: https://go-review.googlesource.com/92705
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Rick Hudson <rlh@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Calls to writebarrierptr can simply be actual pointer writes. Calls to
writebarrierptr_prewrite need to go through the write barrier buffer.
Updates #22460.
Change-Id: I92cee4da98c5baa499f1977563757c76f95bf0ca
Reviewed-on: https://go-review.googlesource.com/92704
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Rick Hudson <rlh@golang.org>
CL 137410043 deleted support for split stacks, which means morestack
no longer needed to save its caller's frame or argument size or its
caller's argument pointer. However, this commit failed to update the
comment or delete the line that computed the caller's argument
pointer. Clean these up now.
Change-Id: I65725d3d42c86e8adb6645d5aa80c305d473363d
Reviewed-on: https://go-review.googlesource.com/92437
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This replaces frame size -4/-8 with the NOFRAME flag in mips and
mips64 assembly.
This was automated with:
sed -i -e 's/\(^TEXT.*[A-Z]\),\( *\)\$-[84]/\1|NOFRAME,\2$0/' $(find -name '*_mips*.s')
Plus a manual fix to mkduff.go.
The go binary is identical on both architectures before and after this
change.
Change-Id: I0310384d1a584118c41d1cd3a042bb8ea7227efb
Reviewed-on: https://go-review.googlesource.com/92044
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This replaces frame size -8 with the NOFRAME flag in arm64 assembly.
This was automated with:
sed -i -e 's/\(^TEXT.*[A-Z]\),\( *\)\$-8/\1|NOFRAME,\2$0/' $(find -name '*_arm64.s')
Plus a manual fix to mkduff.go.
The go binary is identical before and after this change.
Change-Id: I0310384d1a584118c41d1cd3a042bb8ea7227efa
Reviewed-on: https://go-review.googlesource.com/92043
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This replaces frame size -4 with the NOFRAME flag in arm assembly.
This was automated with:
sed -i -e 's/\(^TEXT.*[A-Z]\),\( *\)\$-4/\1|NOFRAME,\2$0/' $(find -name '*_arm.s')
Plus three manual comment changes found by:
grep '\$-4' $(find -name '*_arm.s')
The go binary is identical before and after this change.
Change-Id: I0310384d1a584118c41d1cd3a042bb8ea7227ef9
Reviewed-on: https://go-review.googlesource.com/92042
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
"-8" is not a sensible frame size on arm and we're about to start
rejecting it. Replace it with -4.
Likewise, "-4" is not a sensible frame size on arm64 and we're about
to start rejecting it. Replace it with -8.
Finally, clean up some places we're weirdly inconsistent about using 0
versus -8.
Change-Id: If85e229993d5f7f1f0cfa9852b4e294d053bd784
Reviewed-on: https://go-review.googlesource.com/92038
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
preparePanic must set all registers expected by Go runtime conventions
in case the sigpanic is being injected into C code. However, on
mips64x it fails to restore RSB (R28). As a result, if C code modifies
RSB and then raises a signal that turns into a sigpanic call, sigpanic
may crash when it attempts to lock runtime.debuglock (the first global
it references).
Fix this by restoring RSB in the signal context using the same
convention as main and sigtramp.
Fixes#23641.
Change-Id: Ib47e83df89e2a3eece10f480e4e91ce9e4424388
Reviewed-on: https://go-review.googlesource.com/91156
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Currently, gentraceback suppresses the "unexpected return pc" error
for sigpanic's caller if the M was running C code.
However, there are various situations where a sigpanic is injected
into C code that can cause traceback to unwind *past* the sigpanic
before realizing that it's in trouble (the traceback beyond the
sigpanic will be wrong).
Rather than try to fix these issues for Go 1.10, this CL simply
disables complaining about unexpected return PCs if we're in cgo
regardless of whether or not they're from the sigpanic frame. Go 1.9
never complained about unexpected return PCs when printing, so this is
simply a step closer to the old behavior.
This should fix the openbsd-386 failures on the dashboard, though this
issue could affect any architecture.
Fixes#23640.
Change-Id: I8c32c1ee86a70d2f280661ed1f8caf82549e324b
Reviewed-on: https://go-review.googlesource.com/91136
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
If we're running C code and the code panics, the runtime will inject a
call to sigpanic into the C code just like it would into Go code.
However, the return PC from this sigpanic will be in C code. We used
to silently abort the traceback if we didn't recognize a return PC, so
this went by quietly. Now we're much louder because in general this is
a bad thing. However, in this one particular case, it's fine, so if
we're in cgo and are looking at the return PC of sigpanic, silence the
debug output.
Fixes#23576.
Change-Id: I03d0c14d4e4d25b29b1f5804f5e9ccc4f742f876
Reviewed-on: https://go-review.googlesource.com/90896
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
asmcgocall switches to the system stack and aligns the SP, so
gentraceback both can't unwind over it when it appears on the system
stack (it'll read some uninitialized stack slot as the return PC).
There's also no point in unwinding over it, so don't.
Updates #23576.
Change-Id: Idfcc9599c7636b80dec5451cb65ae892b4611981
Reviewed-on: https://go-review.googlesource.com/90895
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
pprof expects the samples are scaled and reflects unsampled numbers.
The legacy profile parser uses the sampling period in the output
and multiplies all values with the period.
0138a3cd6d/profile/legacy_profile.go (L815)
Apply the same scaling when we output the mutex profile
in the pprof proto format.
Block profile shares the same code, but how to infer unsampled
values is unclear. Legacy profile parser doesn't do anything special
so we do nothing for block profile here.
Tested by checking the profiles reported with debug=0 (proto format)
are similar to the profiles computed from legacy format profile
when the profile rate is a non-trivial number (e.g. 2) manually.
Change-Id: Iaa33f92051deed67d8be43ddffc7c1016db566ca
Reviewed-on: https://go-review.googlesource.com/89295
Reviewed-by: Peter Weinberger <pjw@google.com>
Currently, startpanic_m (which prepares for an unrecoverable panic)
goes out of its way to make it possible to allocate during panic
handling by allocating an mcache if there isn't one.
However, this is both potentially dangerous and unnecessary.
Allocating an mcache is a generally complex thing to do in an already
precarious situation. Specifically, it requires obtaining the heap
lock, and there's evidence that this may be able to deadlock (#23360).
However, it's also unnecessary because we never allocate from the
unrecoverable panic path.
This didn't use to be the case. The call to allocmcache was introduced
long ago, in CL 7388043, where it was in preparation for separating Ms
and Ps and potentially running an M without an mcache. At the time,
after calling startpanic, the runtime could call String and Error
methods on panicked values, which could do anything including
allocating. That was generally unsafe even at the time, and CL 19792
fixed this be pre-printing panic messages before calling startpanic.
As a result, we now no longer allocate after calling startpanic.
This CL not only removes the allocmcache call, but goes a step further
to explicitly disallow any allocation during unrecoverable panic
handling, even in situations where it might be safe. This way, if
panic handling ever does an allocation that would be unsafe in unusual
circumstances, we'll know even if it happens during normal
circumstances.
This would help with debugging #23360, since the deadlock in
allocmcache is currently masking the real failure.
Beyond all.bash, I manually tested this change by adding panics at
various points in early runtime init, signal handling, and the
scheduler to check unusual panic situations.
Change-Id: I85df21e2b4b20c6faf1f13fae266c9339eebc061
Reviewed-on: https://go-review.googlesource.com/88835
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Currently, if a _SigPanic signal arrives in a throwsplit context,
nothing is stopping the runtime from injecting a call to sigpanic that
may attempt to grow the stack. This will fail and, in turn, mask the
real problem.
Fix this by checking for throwsplit in the signal handler itself
before injecting the sigpanic call.
Updates #21431, where this problem is likely masking the real problem.
Change-Id: I64b61ff08e8c4d6f6c0fb01315d7d5e66bf1d3e2
Reviewed-on: https://go-review.googlesource.com/87595
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Currently, if anything goes wrong when printing a traceback, we simply
cut off the traceback without any further diagnostics. Unfortunately,
right now, we have a few issues that are difficult to debug because
the traceback simply cuts off (#21431, #23484).
This is an attempt to improve the debuggability of traceback failure
by printing a diagnostic message plus a hex dump around the failed
traceback frame when something goes wrong.
The failures look like:
goroutine 5 [running]:
runtime: unexpected return pc for main.badLR2 called from 0xbad
stack: frame={sp:0xc42004dfa8, fp:0xc42004dfc8} stack=[0xc42004d800,0xc42004e000)
000000c42004dea8: 0000000000000001 0000000000000001
000000c42004deb8: 000000c42004ded8 000000c42004ded8
000000c42004dec8: 0000000000427eea <runtime.dopanic+74> 000000c42004ded8
000000c42004ded8: 000000000044df70 <runtime.dopanic.func1+0> 000000c420001080
000000c42004dee8: 0000000000427b21 <runtime.gopanic+961> 000000c42004df08
000000c42004def8: 000000c42004df98 0000000000427b21 <runtime.gopanic+961>
000000c42004df08: 0000000000000000 0000000000000000
000000c42004df18: 0000000000000000 0000000000000000
000000c42004df28: 0000000000000000 0000000000000000
000000c42004df38: 0000000000000000 000000c420001080
000000c42004df48: 0000000000000000 0000000000000000
000000c42004df58: 0000000000000000 0000000000000000
000000c42004df68: 000000c4200010a0 0000000000000000
000000c42004df78: 00000000004c6400 00000000005031d0
000000c42004df88: 0000000000000000 0000000000000000
000000c42004df98: 000000c42004dfb8 00000000004ae7d9 <main.badLR2+73>
000000c42004dfa8: <00000000004c6400 00000000005031d0
000000c42004dfb8: 000000c42004dfd0 !0000000000000bad
000000c42004dfc8: >0000000000000000 0000000000000000
000000c42004dfd8: 0000000000451821 <runtime.goexit+1> 0000000000000000
000000c42004dfe8: 0000000000000000 0000000000000000
000000c42004dff8: 0000000000000000
main.badLR2(0x0)
/go/src/runtime/testdata/testprog/badtraceback.go:42 +0x49
For #21431, #23484.
Change-Id: I8718fc76ced81adb0b4b0b4f2293f3219ca80786
Reviewed-on: https://go-review.googlesource.com/89016
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Fix breakage introduced in CL 70530.
Change-Id: I87f3da6b20554d4f405a1143b0d894c5953b63aa
Reviewed-on: https://go-review.googlesource.com/88516
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
We used a mix of both before.
I've never heard anybody say "an arr-double you mutex" when speaking.
Fixes#23457
Change-Id: I802b5eb2339f885ca9d24607eeda565763165298
Reviewed-on: https://go-review.googlesource.com/87896
Reviewed-by: Andrew Bonventre <andybons@golang.org>
CL 67332 created the fast no-syscall path for time.Now in High Sierra
but managed to break Sierra and older by forcing them into the slow
syscall path: the version check based on commpage version was wrong.
This CL uses the Darwin version number instead.
The assembly diff is noisy because many variables had to be
renamed, but the only actual change is the version check.
Fixes#23419.
Change-Id: Ie31ef5fb88f66d1517a8693942a7fb6100c213b0
Reviewed-on: https://go-review.googlesource.com/87655
Run-TryBot: Giovanni Bajo <rasky@develer.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
The tool was moved to tools/Testing/selftests within the Linux kernel
source tree. Adjust the URL in the comments of vdso_linux.go
Change-Id: I86b9cae4b898c4a45bc7c54891ce6ead91a22670
Reviewed-on: https://go-review.googlesource.com/87815
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The cgo checker was issuing an error with cgocheck=2 when a timer
bucket was stored in a pollDesc. The pollDesc values are allocated
using persistentalloc, so they are not in the Go heap. The code is OK
since timer bucket pointers point into a global array, and as such are
never garbage collected or moved.
Mark timersBucket notinheap to avoid the problem. timersBucket values
only occur in the global timers array.
Fixes#23435
Change-Id: I835f31caafd54cdacc692db5989de63bb49e7697
Reviewed-on: https://go-review.googlesource.com/87637
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Suppose you build the Go toolchain in directory A,
move the whole thing to directory B, and then use
it from B to build a new program hello.exe, and then
run hello.exe, and hello.exe crashes with a stack
trace into the standard library.
Long ago, you'd have seen hello.exe print file names
in the A directory tree, even though the files had moved
to the B directory tree. About two years ago we changed
the compiler to write down these files with the name
"$GOROOT" (that literal string) instead of A, so that the
final link from B could replace "$GOROOT" with B,
so that hello.exe's crash would show the correct source
file paths in the stack trace. (golang.org/cl/18200)
Now suppose that you do the same thing but hello.exe
doesn't crash: it prints fmt.Println(runtime.GOROOT()).
And you run hello.exe after clearing $GOROOT from the
environment.
Long ago, you'd have seen hello.exe print A instead of B.
Before this CL, you'd still see hello.exe print A instead of B.
This case is the one instance where a moved toolchain
still divulges its origin. Not anymore. After this CL, hello.exe
will print B, because the linker sets runtime/internal/sys.DefaultGoroot
with the effective GOROOT from link time.
This makes the default result of runtime.GOROOT once again
match the file names recorded in the binary, after two years
of divergence.
With that cleared up, we can reintroduce GOROOT into the
link action ID and also reenable TestExecutableGOROOT/RelocatedExe.
When $GOROOT_FINAL is set during link, it is used
in preference to $GOROOT, as always, but it was easier
to explain the behavior above without introducing that
complication.
Fixes#22155.
Fixes#20284.
Fixes#22475.
Change-Id: Ifdaeb77fd4678fdb337cf59ee25b2cd873ec1016
Reviewed-on: https://go-review.googlesource.com/86835
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
findrunnable loops over allp to check run queues *after* it has
dropped its own P. This is unsafe because allp can change when nothing
is blocking safe-points. Hence, procresize could change allp
concurrently with findrunnable's loop. Beyond generally violating Go's
memory model, in the best case this could findrunnable to observe a
nil P pointer if allp has been grown but the new slots not yet
initialized. In the worst case, the reads of allp could tear, causing
findrunnable to read a word that isn't even a valid *P pointer.
Fix this by taking a snapshot of the allp slice header (but not the
backing store) before findrunnable drops its P and iterating over this
snapshot. The actual contents of allp are immutable up to len(allp),
so this fixes the race.
Updates #23098 (may fix).
Change-Id: I556ae2dbfffe9fe4a1bf43126e930b9e5c240ea8
Reviewed-on: https://go-review.googlesource.com/86215
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Commit c2c07c7989 (CL 49331) changed the linker and runtime to always
use 2MB stacks on 64-bit Windows. This is the corresponding change to
make 32-bit Windows always use large (1MB) stacks because it's
difficult to detect when Windows applications will call into arbitrary
C code that may expect a large stack.
This is done as a separate change because it's possible this will
cause too much address space pressure for a 32-bit address space. On
the other hand, cgo binaries on Windows already use 1MB stacks and
there haven't been complaints.
Updates #20975.
Change-Id: I8ce583f07cb52254fb4bd47250f1ef2b789bc490
Reviewed-on: https://go-review.googlesource.com/49610
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
golang.org/cl/81315 attempted to distinguish system goroutines
by examining the function name in the goroutine stack. It assumes that
the information would be available when GoSysBlock or GoInSyscall
events are processed, but it turned out the stack information is
set too late (when the goroutine gets a chance to run).
This change initializes the goroutine information entry when
processing GoCreate event which should be one of the very first
events for the every goroutine in trace.
Fixes#22574
Change-Id: I1ed37087ce2e78ed27c9b419b7d942eb4140cc69
Reviewed-on: https://go-review.googlesource.com/83595
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This attempts to symbolize the PC of morestack's caller when there's a
stack split at a bad time. The stack trace starts at the *caller* of
the function that attempted to grow the stack, so this is useful if it
isn't obvious what's being called at that point, such as in #21431.
Change-Id: I5dee305d87c8069611de2d14e7a3083d76264f8f
Reviewed-on: https://go-review.googlesource.com/84115
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Currently, wbBufFlush does nothing if the goroutine is dying on the
assumption that the system is crashing anyway and running the write
barrier may crash it even more. However, it fails to reset the
buffer's "next" pointer. As a result, if there are later write
barriers on the same P, the write barrier will overflow the write
barrier buffer and start corrupting other fields in the P or other
heap objects. Often, this corrupts fields in the next allocated P
since they tend to be together in the heap.
Fix this by always resetting the buffer's "next" pointer, even if
we're not doing anything with the pointers in the buffer.
Updates #22987 and #22988. (May fix; it's hard to say.)
Change-Id: I82c11ea2d399e1658531c3e8065445a66b7282b2
Reviewed-on: https://go-review.googlesource.com/83016
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
heapBits.bits is used during bulkBarrierPreWrite via
heapBits.isPointer, which means it must not be preempted. If it is
preempted, several bad things can happen:
1. This could allow a GC phase change, and the resulting shear between
the barriers and the memory writes could result in a lost pointer.
2. Since bulkBarrierPreWrite uses the P's local write barrier buffer,
if it also migrates to a different P, it could try to append to the
write barrier buffer concurrently with another write barrier. This can
result in the buffer's next pointer skipping over its end pointer,
which results in a buffer overflow that can corrupt arbitrary other
fields in the Ps (or anything in the heap, really, but it'll probably
crash from the corrupted P quickly).
Fix this by marking heapBits.bits go:nosplit. This would be the
perfect use for a recursive no-preempt annotation (#21314).
This doesn't actually affect any binaries because this function was
always inlined anyway. (I discovered it when I was modifying heapBits
and make h.bits() no longer inline, which led to rampant crashes from
problem 2 above.)
Updates #22987 and #22988 (but doesn't fix because it doesn't actually
change the generated code).
Change-Id: I60ebb928b1233b0613361ac3d0558d7b1cb65610
Reviewed-on: https://go-review.googlesource.com/83015
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Rick Hudson <rlh@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
On DragonFly mmap with MAP_STACK returns the top of the region, not
the bottom. Rather than try to cope, just don't use the flag anywhere.
Fixes#23061
Change-Id: Ib5df4dd7c934b3efecfc4bc87f8989b4c37555d7
Reviewed-on: https://go-review.googlesource.com/83035
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
This change updates runtime.semasleep to no longer call
runtime.nanotime and instead calls lwp_park with a duration to sleep
relative to the monotonic clock, so the nanotime is never called.
(This requires updating to a newer version of the lwp_park system
call, which is safe, because Go 1.10 will require the unreleased
NetBSD 8+ anyway)
Additionally, this change makes the nanotime function use the
monotonic clock for netbsd/arm, which was forgotten from
https://golang.org/cl/81135 which updated netbsd/amd64 and netbsd/386.
Because semasleep previously depended on nanotime, the past few days
of netbsd have likely been unstable because lwp_park was then mixing
the monotonic and wall clocks. After this CL, lwp_park no longer
depends on nanotime.
Original patch submitted at:
https://www.netbsd.org/~christos/go-lwp-park-clock-monotonic.diff
This commit message (any any mistakes therein) were written by Brad
Fitzpatrick. (Brad migrated the patch to Gerrit and checked CLAs)
Updates #6007Fixes#22968
Also updates netbsd/arm to use monotonic time for
Change-Id: If77ef7dc610b3025831d84cdfadfbbba2c52acb2
Reviewed-on: https://go-review.googlesource.com/81715
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
MAP_ANON is the deprecated but more portable spelling of
MAP_ANONYMOUS. Use MAP_ANON to un-break the Darwin 10.10 builder.
Updates #22930.
Change-Id: Iedd6232b94390b3b2a7423c45cdcb25c1a5b3323
Reviewed-on: https://go-review.googlesource.com/81615
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Minor.
Makes reading failing runtime test stacktraces easier (by having fewer
goroutines to read) on machines where these gdb tests wouldn't have
ever run anyway.
Change-Id: I3fab0667e017f20ef3bf96a8cc4cfcc614d25b5c
Reviewed-on: https://go-review.googlesource.com/81575
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This adds logging for the expected duration of a growStack, plus
progress information on the growStack that timed out.
Updates #19381.
Change-Id: Ic358f8350f499ff22dd213b658aece7d1aa62675
Reviewed-on: https://go-review.googlesource.com/81556
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
I think of "sending" a signal as calling kill, but sigsend is involved
in handling a signal and, specifically delivering it to the internal
signal queue. The term "delivery" is already used in
signalWaitUntilIdle, so this CL also uses it in the documentation for
sigsend.
Change-Id: I86e171f247f525ece884a680bace616fa9a3c7bd
Reviewed-on: https://go-review.googlesource.com/81235
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Currently, when we minit on a thread that already has an alternate
signal stack (e.g., because the M was an extram being used for a cgo
callback, or to handle a signal on a C thread, or because the
platform's libc always allocates a signal stack like on Android), we
simply drop the Go-allocated gsignal stack on the floor.
This is a problem for Ms on the extram list because those Ms may later
be reused for a different thread that may not have its own alternate
signal stack. On tip, this manifests as a crash in sigaltstack because
we clear the gsignal stack bounds in unminit and later try to use
those cleared bounds when we re-minit that M. On 1.9 and earlier, we
didn't clear the bounds, so this manifests as running more than one
signal handler on the same signal stack, which could lead to arbitrary
memory corruption.
This CL fixes this problem by saving the Go-allocated gsignal stack in
a new field in the m struct when overwriting it with a system-provided
signal stack, and then restoring the original gsignal stack in
unminit.
This CL is designed to be easy to back-port to 1.9. It won't quite
cherry-pick cleanly, but it should be sufficient to simply ignore the
change in mexit (which didn't exist in 1.9).
Now that we always have a place to stash the original signal stack in
the m struct, there are some simplifications we can make to the signal
stack handling. We'll do those in a later CL.
Fixes#22930.
Change-Id: I55c5a6dd9d97532f131146afdef0b216e1433054
Reviewed-on: https://go-review.googlesource.com/81476
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This reverts commit 08f19bbde1.
Reason for revert:
The changed transformation takes effect on a larger set
of code snippets than expected.
For example, this:
func foo() {
// Comment
bar()
}
becomes:
func foo() {
// Comment
bar()
}
This is an unintended consequence.
Change-Id: Ifca88d6267dab8a8170791f7205124712bf8ace8
Reviewed-on: https://go-review.googlesource.com/81335
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Joe Tsai <joetsai@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Otherwise we may delay the delivery of these signals for an arbitrary
length of time. We are already careful to not block signals that the
program has asked to see.
Also make sure that we don't miss a signal delivery if a thread
decides to stop for a while while executing the signal handler.
Also clean up the TestAtomicStop output a little bit.
Fixes#21433
Change-Id: Ic0c1a4eaf7eba80d1abc1e9537570bf4687c2434
Reviewed-on: https://go-review.googlesource.com/79581
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Compiler and linker changes to support DWARF inlined instances,
see https://go.googlesource.com/proposal/+/HEAD/design/22080-dwarf-inlining.md
for design details.
This functionality is gated via the cmd/compile option -gendwarfinl=N,
where N={0,1,2}, where a value of 0 disables dwarf inline generation,
a value of 1 turns on dwarf generation without tracking of formal/local
vars from inlined routines, and a value of 2 enables inlines with
variable tracking.
Updates #22080
Change-Id: I69309b3b815d9fed04aebddc0b8d33d0dbbfad6e
Reviewed-on: https://go-review.googlesource.com/75550
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
This CL is a simple doc typo fix, uncovered while reviewing the go-wasm
port.
Change-Id: I0fce915c341aaaea3a7cc365819abbc5f2c468c3
Reviewed-on: https://go-review.googlesource.com/80715
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Thanks to coypoop for noticing at:
https://github.com/golang/go/issues/22914#issuecomment-347761838
FreeBSD/386 and NetBSD/386 diverged between Go 1.4 and Go 1.5 when
Russ sent https://golang.org/cl/135830043 (git rev 25f6b02ab0)
to change the calling convention of the C compilers to match Go.
But netbsd wasn't updated.
Tested on a NetBSD/386 VM, since the builders aren't back up yet (due
to this bug)
Fixes#22914
Updates #19339
Updates #20852
Updates #16511
Change-Id: Id76ebe8f29bcc85e39b1c11090639d906cd6cf04
Reviewed-on: https://go-review.googlesource.com/80515
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Benny Siegert <bsiegert@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TestGdbAutotmpTypes times out for unknown reasons on NetBSd. Skip the
gdb tests on NetBSD for now.
Updates #22893
Change-Id: Ibb05b7260eabb74d805d374b25a43770939fa5f2
Reviewed-on: https://go-review.googlesource.com/80136
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
exitsyscall should be recursively nosplit, but we don't have a way to
annotate that right now (see #21314). There's exactly one remaining
place where this is violated right now: exitsyscall -> casgstatus ->
print. The other prints in casgstatus are wrapped in systemstack
calls. This fixes the remaining print.
Updates #21431 (in theory could fix it, but that would just indicate
that we have a different G status-related crash and we've *never* seen
that failure on the dashboard.)
Change-Id: I9a5e8d942adce4a5c78cfc6b306ea5bda90dbd33
Reviewed-on: https://go-review.googlesource.com/79815
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Rick Hudson <rlh@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Use singular form of panic and remove the unnecessary
'however', when comparing Goexit's behavior to 'a panic'
as well as what happens for deferred recovers with Goexit.
Change-Id: I3116df3336fa135198f6a39cf93dbb88a0e2f46e
Reviewed-on: https://go-review.googlesource.com/79755
Reviewed-by: Rob Pike <r@golang.org>
Add an explanation of why sigtrampgo is nosplit.
Updates #21314.
Change-Id: I3f5909d2b2c180f9fa74d53df13e501826fd4316
Reviewed-on: https://go-review.googlesource.com/79615
Reviewed-by: Ian Lance Taylor <iant@golang.org>
newstack manually prints the stack trace if we try to grow the stack
when throwsplit is set. However, the default behavior is to omit
runtime frames. Since runtime frames can be critical to understanding
this crash, this change fixes this traceback to include them.
Updates #21431.
Change-Id: I5aa43f43aa2f10a8de7d67bcec743427be3a3b5d
Reviewed-on: https://go-review.googlesource.com/79518
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
If exitsyscall tries to grow the stack it will panic, but throw calls
print, which can grow the stack. Move the two bare throws in
exitsyscall to the system stack.
Updates #21431.
Change-Id: I5b29da5d34ade908af648a12075ed327a864476c
Reviewed-on: https://go-review.googlesource.com/79517
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Currently, SetGCPercent(-1) disables GC, but doesn't wait for any
currently running concurrent GC to finish, so GC can still be running
when it returns. This is a change in behavior from Go 1.8, probably
defies user expectations, and can break various runtime tests that
depend on SetGCPercent(-1) to disable garbage collection in order to
prevent preemption deadlocks.
Fix this by making SetGCPercent(-1) block until any concurrently
running GC cycle finishes.
Fixes#22443.
Change-Id: I904133a34acf97a7942ef4531ace0647b13930ef
Reviewed-on: https://go-review.googlesource.com/79195
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The signature of the mapassign_fast* routines need to distinguish
the pointerness of their key argument. If the affected routines
suspend part way through, the object pointed to by the key might
get garbage collected because the key is typed as a uint{32,64}.
This is not a problem for mapaccess or mapdelete because the key
in those situations do not live beyond the call involved. If the
object referenced by the key is garbage collected prematurely, the
code still works fine. Even if that object is subsequently reallocated,
it can't be written to the map in time to affect the lookup/delete.
Fixes#22781
Change-Id: I0bbbc5e9883d5ce702faf4e655348be1191ee439
Reviewed-on: https://go-review.googlesource.com/79018
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Martin Möhrmann <moehrmann@google.com>
CL 78538 was updated after running TryBots to depend on
syscall.NanoSleep which isn't available on all non-Linux platforms.
Change-Id: I1fa615232b3920453431861310c108b208628441
Reviewed-on: https://go-review.googlesource.com/79175
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Adding s390x to the list of architectures that support c-shared and c-archive.
Required adding load-time initialization (via _rt0_s390x_linux_lib) and adding s390x
to the c-shared and c-archive tests.
Change-Id: I75883b2891c310fe8ce7f08c27b06895c074e123
Reviewed-on: https://go-review.googlesource.com/74910
Reviewed-by: Michael Munday <mike.munday@ibm.com>
I experimented with changing the write barrier to take the value in SI
rather than AX to improve register allocation. It had no effect on
performance and only made the "hello world" text 0.07% smaller, so
let's just remove the comment.
Change-Id: I6a261d14139b7a02a8467b31e74951dfb927ffb4
Reviewed-on: https://go-review.googlesource.com/78033
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
The CPU time reported in the gctrace for STW phases is simply
work.stwprocs times the wall-clock duration of these phases. However,
work.stwprocs is set to gcprocs(), which is wrong for multiple
reasons:
1. gcprocs is intended to limit the number of Ms used for mark
termination based on how well the garbage collector actually
scales, but the gctrace wants to report how much CPU time is being
stolen from the application. During STW, that's *all* of the CPU,
regardless of how many the garbage collector can actually use.
2. gcprocs assumes it's being called during STW, so it limits its
result to sched.nmidle+1. However, we're not calling it during STW,
so sched.nmidle is typically quite small, even if GOMAXPROCS is
quite large.
Fix this by setting work.stwprocs to min(ncpu, GOMAXPROCS). This also
fixes the overall GC CPU fraction, which is based on the computed CPU
times.
Fixes#22725.
Change-Id: I64b5ce87e28dbec6870aa068ce7aecdd28c058d1
Reviewed-on: https://go-review.googlesource.com/77710
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
change hash/crc32 package to use cpu package instead of using
runtime internal variables to check crc32 instruction
Change-Id: I8f88d2351bde8ed4e256f9adf822a08b9a00f532
Reviewed-on: https://go-review.googlesource.com/76490
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Just copy some code to make TestWindowsStackMemory build
when CGO_ENABLED is set to 0.
Fixes#22680
Change-Id: I63f9b409a3a97b7718f5d37837ab706d8ed92e81
Reviewed-on: https://go-review.googlesource.com/77430
Reviewed-by: Chris Hines <chris.cs.guy@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
CL 45412 started hiding autogenerated wrapper functions from call
stacks so that call stack semantics better matched language semantics.
This is based on the theory that the wrapper function will call the
"real" function and all the programmer knows about is the real
function.
However, this theory breaks down in two cases:
1. If the wrapper is at the top of the stack, then it didn't call
anything. This can happen, for example, if the "stack" was actually
synthesized by the user.
2. If the wrapper panics, for example by calling panicwrap or by
dereferencing a nil pointer, then it didn't call the wrapped
function and the user needs to see what panicked, even if we can't
attribute it nicely.
This commit modifies the traceback logic to include the wrapper
function in both of these cases.
Fixes#22231.
Change-Id: I6e4339a652f73038bd8331884320f0b8edd86eb1
Reviewed-on: https://go-review.googlesource.com/76770
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
It has always been problematic that there was no way to specify
tool flags that applied only to the build of certain packages;
it was only to specify flags for all packages being built.
The usual workaround was to install all dependencies of something,
then build just that one thing with different flags. Since the
dependencies appeared to be up-to-date, they were not rebuilt
with the different flags. The new content-based staleness
(up-to-date) checks see through this trick, because they detect
changes in flags. This forces us to address the underlying problem
of providing a way to specify per-package flags.
The solution is to allow -gcflags=pattern=flags, which means
that flags apply to packages matching pattern, in addition to the
usual -gcflags=flags, which is now redefined to apply only to
the packages named on the command line.
See #22527 for discussion and rationale.
Fixes#22527.
Change-Id: I6716bed69edc324767f707b5bbf3aaa90e8e7302
Reviewed-on: https://go-review.googlesource.com/76551
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Currently dead goroutines retain their assist credit. This credit can
be used if the goroutine gets recycled, but in general this can make
assist pacing over-aggressive by hiding an amount of credit
proportional to the number of exited (and not reused) goroutines.
Fix this "hidden credit" by flushing assist credit to the global
credit pool when a goroutine exits.
Updates #14812.
Change-Id: I65f7f75907ab6395c04aacea2c97aea963b60344
Reviewed-on: https://go-review.googlesource.com/24703
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
This fixes a race on old Linux kernels, in which we might temporarily
set epfd to an invalid value other than -1. It's also the right thing
to do. No test because the problem only occurs on old kernels.
Fixes#22606
Change-Id: Id84bdd6ae6d7c5d47c39e97b74da27576cb51a54
Reviewed-on: https://go-review.googlesource.com/76319
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
A couple of the CPU profiling testpoints make calls to helper
functions (cpuHog1, for example) where the computed value is always
thrown away by the caller without being used. A smart compiler back
end (in this case LLVM) can detect this fact and delete the contents
of the called function, which can cause tests to fail. Harden the test
slighly by passing in a value read from a global and insuring that the
caller stores the value back to a global; this prevents any optimizer
mischief.
Change-Id: Icbd6e3e32ff299c68a6397dc1404a52b21eaeaab
Reviewed-on: https://go-review.googlesource.com/76230
Run-TryBot: Than McIntosh <thanm@google.com>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
This CL adds an automatic, limited "go vet" to "go test".
If the building of a test package fails, vet is not run.
If vet fails, the test is not run.
The goal is that users don't notice vet as part of the "go test"
process at all, until vet speaks up and says something important.
This should help users find real problems in their code faster
(vet can just point to them instead of needing to debug a
test failure) and expands the scope of what kinds of things
vet can help with.
The "go vet" runs in parallel with the linking of the test binary,
so for incremental builds it typically does not slow the overall
"go test" at all: there's spare machine capacity during the link.
all.bash has less spare machine capacity. This CL increases
the time for all.bash on my laptop from 4m41s to 4m48s (+2.5%)
To opt out for a given run, use "go test -vet=off".
The vet checks used during "go test" are a subset of the full set,
restricted to ones that are 100% correct and therefore acceptable
to make mandatory. In this CL, that set is atomic, bool, buildtags,
nilfunc, and printf. Including printf is debatable, but I want to
include it for now and find out what needs to be scaled back.
(It already found one real problem in package os's tests that
previous go vet os had not turned up.)
Now that we can rely on type information it may be that printf
should make its function-name-based heuristic less aggressive
and have a whitelist of known print/printf functions.
Determining the exact set for Go 1.10 is #18085.
Running vet also means that programs now have to type-check
with both cmd/compile and go/types in order to pass "go test".
We don't start vet until cmd/compile has built the test package,
so normally the added go/types check doesn't find anything.
However, there is at least one instance where go/types is more
precise than cmd/compile: declared and not used errors involving
variables captured into closures.
This CL includes a printf fix to os/os_test.go and many declared
and not used fixes in the race detector tests.
Fixes#18084.
Change-Id: I353e00b9d1f9fec540c7557db5653e7501f5e1c9
Reviewed-on: https://go-review.googlesource.com/74356
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Unlike the legacy text format that outputs the count and the number of
cycles, the pprof tool expects contention profiles to include the count
and the delay time measured in nanoseconds. printCountCycleProfile
performs the conversion from cycles to nanoseconds.
(See parseContention function in
cmd/vendor/github.com/google/pprof/profile/legacy_profile.go)
Fixes#21474
Change-Id: I8e8fb6ea803822d7eaaf9ecf1df3e236ad225a7b
Reviewed-on: https://go-review.googlesource.com/64410
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
The current GOROOT documentation could indicate that changing the
environment variable at runtime would affect the return value of
GOROOT. This is false as the returned value is the one used for the
build. This CL aims to clarify the confusion.
Fixes#22302
Change-Id: Ib68c30567ac864f152d2da31f001a98531fc9757
Reviewed-on: https://go-review.googlesource.com/75751
Reviewed-by: Russ Cox <rsc@golang.org>
The current code can potentially return a smaller processor count on a
linux kernel when its cpumask_size (controlled by both kernel config and
boot parameter) is not a multiple of the pointer size, because
r/sys.PtrSize will be rounded down. Since sched_getaffinity returns the
size in bytes, we can just allocate the buf as a byte array to avoid the
extra calculation with the pointer size and roundups.
Change-Id: I0c21046012b88d8a56b5dd3dde1d158d94f8eea9
Reviewed-on: https://go-review.googlesource.com/75591
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
To improve readability when exported fields are removed,
forbid the printer from emitting an empty line before the first comment
in a const, var, or type block.
Also, when printing the "Has filtered or unexported fields." message,
add an empty line before it to separate the message from the struct
or interfact contents.
Before the change:
<<<
type NamedArg struct {
// Name is the name of the parameter placeholder.
//
// If empty, the ordinal position in the argument list will be
// used.
//
// Name must omit any symbol prefix.
Name string
// Value is the value of the parameter.
// It may be assigned the same value types as the query
// arguments.
Value interface{}
// contains filtered or unexported fields
}
>>>
After the change:
<<<
type NamedArg struct {
// Name is the name of the parameter placeholder.
//
// If empty, the ordinal position in the argument list will be
// used.
//
// Name must omit any symbol prefix.
Name string
// Value is the value of the parameter.
// It may be assigned the same value types as the query
// arguments.
Value interface{}
// contains filtered or unexported fields
}
>>>
Fixes#18264
Change-Id: I9fe17ca39cf92fcdfea55064bd2eaa784ce48c88
Reviewed-on: https://go-review.googlesource.com/71990
Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
* Avoid calculating insertk until needed.
* Avoid a pointer into b.tophash and just track the insertion index.
This avoids b.tophash being marked as escaping to heap.
* Calculate val only once at the end of the mapassign functions.
Function sizes decrease slightly, e.g. for mapassign_faststr:
before "".mapassign_faststr STEXT size=1166 args=0x28 locals=0x78
after "".mapassign_faststr STEXT size=1080 args=0x28 locals=0x68
name old time/op new time/op delta
MapAssign/Int32/256-4 19.4ns ± 4% 19.5ns ±11% ~ (p=0.973 n=20+20)
MapAssign/Int32/65536-4 32.5ns ± 2% 32.4ns ± 3% ~ (p=0.078 n=20+19)
MapAssign/Int64/256-4 20.3ns ± 6% 17.6ns ± 5% -13.01% (p=0.000 n=20+20)
MapAssign/Int64/65536-4 33.3ns ± 2% 33.3ns ± 1% ~ (p=0.444 n=20+20)
MapAssign/Str/256-4 22.3ns ± 3% 22.4ns ± 3% ~ (p=0.343 n=20+20)
MapAssign/Str/65536-4 44.9ns ± 1% 43.9ns ± 1% -2.39% (p=0.000 n=20+19)
Change-Id: I2627bb8a961d366d9473b5922fa129176319eb22
Reviewed-on: https://go-review.googlesource.com/74870
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Handle make(map[any]any) and make(map[any]any, hint) where
hint <= BUCKETSIZE special to allow for faster map initialization
and to improve binary size by using runtime calls with fewer arguments.
Given hint is smaller or equal to BUCKETSIZE in which case
overLoadFactor(hint, 0) is false and no buckets would be allocated by makemap:
* If hmap needs to be allocated on the stack then only hmap's hash0
field needs to be initialized and no call to makemap is needed.
* If hmap needs to be allocated on the heap then a new special
makehmap function will allocate hmap and intialize hmap's
hash0 field.
Reduces size of the godoc by ~36kb.
AMD64
name old time/op new time/op delta
NewEmptyMap 16.6ns ± 2% 5.5ns ± 2% -66.72% (p=0.000 n=10+10)
NewSmallMap 64.8ns ± 1% 56.5ns ± 1% -12.75% (p=0.000 n=9+10)
Updates #6853
Change-Id: I624e90da6775afaa061178e95db8aca674f44e9b
Reviewed-on: https://go-review.googlesource.com/61190
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Since CL 33071, testCPUProfile is only one user of the badOS map.
Replace it by the corresponding switch, with the "plan9" case removed
because it is already checked earlier in the same function.
Change-Id: Id647b8ee1fd37516bb702b35b3c9296a4f56b61b
Reviewed-on: https://go-review.googlesource.com/75110
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The check of uintptr(newcap) > maxSliceCap(et.size) in addition
to capmem > _MaxMem is needed to prevent a reproducible overflow
on 32bit architectures.
On 64bit platforms this problem is less likely to occur as allocation
of a sufficiently large array or slice to be append is likely to
already exhaust available memory before the call to append can be made.
Example program that without the fix in this CL does segfault on 386:
type T [1<<27 + 1]int64
var d T
var s []T
func main() {
s = append(s, d, d, d, d)
print(len(s), "\n")
}
Fixes#21586
Change-Id: Ib4185435826ef43df71ba0f789e19f5bf9a347e6
Reviewed-on: https://go-review.googlesource.com/55133
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
testing.Skip{,f} will exit the test via runtime.Goexit. Thus, the
successive return is never reached and can be removed.
Change-Id: I1e399f3d5db753ece1ffba648850427e1b4be300
Reviewed-on: https://go-review.googlesource.com/74990
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Otherwise the new numbered directories like b028/ appear in the objects,
and they can change from run to run.
Fixes#22514.
Change-Id: I8d0cf65f3622e48b2547d5757febe0ee1301e2ed
Reviewed-on: https://go-review.googlesource.com/74791
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Since Go1.8, different types of GC mark workers were annotated and the
annotation strings were recorded during StartTrace. This change fixes
two issues around the use of traceString from StartTrace here.
1) "failed to parse trace: no consistent ordering of events possible"
This issue is a result of a missing 'batch' event entry. For efficient
tracing, tracer maintains system allocated buffers and once a buffer
is full, it is Flushed out for writing. Moreover, tracing assumes all
the records in the same buffer (batch) are already ordered and implements
more optimization in encoding and defers the completing order
reconstruction till the trace parsing time. Thus, when a Flush happens
and a new buffer is used, the new buffer should contain an event to
indicate the start of a new batch. Before this CL, the batch entry was
written only by traceEvent only when the buffer position is 0 and
wasn't written when flush occurs during traceString.
This CL fixes it by moving the batch entry write to the traceFlush.
2) crash during tracing due to invalid memory access, or during parsing
due to duplicate string entries
This issue is a result of memory allocation during traceString calls.
Execution tracer traces some memory allocation activities. Before this
CL, traceString took the buffer address (*traceBuf) and mutated the buffer.
If memory tracing occurs in the meantime from the same P, the allocation
tracing (traceEvent) will take the same buffer address through the pointer
to the buffer address (**traceBuf), and mutate the buffer.
As a result, one of the followings can happen:
- the allocation record is overwritten by the following trace string
record (data loss)
- if buffer flush occurs during the allocation tracing, traceString
will attempt to write the string record to the old buffer and
eventually causes invalid memory access crash.
- or flush on the same buffer can occur twice (once from the memory
allocation, and once from the string record write), and in this case
the trace can contain the same data twice and the parse will complain
about duplicate string record entries.
This CL fixes the second issue by making the traceString take
**traceBuf (*traceBufPtr).
Change-Id: I24f629758625b38e1916fbfc7d7be6ea210586af
Reviewed-on: https://go-review.googlesource.com/50873
Run-TryBot: Austin Clements <austin@google.com>
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Currently, both the background mark worker and the goal GC CPU are
both fixed at 25%. The trigger controller's goal is to achieve the
goal CPU usage, and with the previous commit it can actually achieve
this. But this means there are *no* assists, which sounds ideal but
actually causes problems for the trigger controller. Since the
controller can't lower CPU usage below the background mark worker CPU,
it saturates at the CPU goal and no longer gets feedback, which
translates into higher variability in heap growth.
This commit fixes this by allowing assists 5% CPU beyond the 25% fixed
background mark. This avoids saturating the trigger controller, since
it can now get feedback from both sides of the CPU goal. This leads to
low variability in both CPU usage and heap growth, at the cost of
reintroducing a low rate of mark assists.
We also experimented with 20% background plus 5% assist, but 25%+5%
clearly performed better in benchmarks.
Updates #14951.
Updates #14812.
Updates #18534.
Combined with the previous CL, this significantly improves tail
mutator utilization in the x/bechmarks garbage benchmark. On a sample
trace, it increased the 99.9%ile mutator utilization at 10ms from 26%
to 59%, and at 5ms from 17% to 52%. It reduced the 99.9%ile zero
utilization window from 2ms to 700µs. It also helps the mean mutator
utilization: it increased the 10s mutator utilization from 83% to 94%.
The minimum mutator utilization is also somewhat improved, though
there is still some unknown artifact that causes a miniscule fraction
of mutator assists to take 5--10ms (in fact, there was exactly one
10ms mutator assist in my sample trace).
This has no significant effect on the throughput of the
github.com/dr2chase/bent benchmarks-50.
This has little effect on the go1 benchmarks (and the slight overall
improvement makes up for the slight overall slowdown from the previous
commit):
name old time/op new time/op delta
BinaryTree17-12 2.40s ± 0% 2.41s ± 1% +0.26% (p=0.010 n=18+19)
Fannkuch11-12 2.95s ± 0% 2.93s ± 0% -0.62% (p=0.000 n=18+15)
FmtFprintfEmpty-12 42.2ns ± 0% 42.3ns ± 1% +0.37% (p=0.001 n=15+14)
FmtFprintfString-12 67.9ns ± 2% 67.2ns ± 3% -1.03% (p=0.002 n=20+18)
FmtFprintfInt-12 75.6ns ± 3% 76.8ns ± 2% +1.59% (p=0.000 n=19+17)
FmtFprintfIntInt-12 123ns ± 1% 124ns ± 1% +0.77% (p=0.000 n=17+14)
FmtFprintfPrefixedInt-12 148ns ± 1% 150ns ± 1% +1.28% (p=0.000 n=20+20)
FmtFprintfFloat-12 212ns ± 0% 211ns ± 1% -0.67% (p=0.000 n=16+17)
FmtManyArgs-12 499ns ± 1% 500ns ± 0% +0.23% (p=0.004 n=19+16)
GobDecode-12 6.49ms ± 1% 6.51ms ± 1% +0.32% (p=0.008 n=19+19)
GobEncode-12 5.47ms ± 0% 5.43ms ± 1% -0.68% (p=0.000 n=19+20)
Gzip-12 220ms ± 1% 216ms ± 1% -1.66% (p=0.000 n=20+19)
Gunzip-12 38.8ms ± 0% 38.5ms ± 0% -0.80% (p=0.000 n=19+20)
HTTPClientServer-12 78.5µs ± 1% 78.1µs ± 1% -0.53% (p=0.008 n=20+19)
JSONEncode-12 12.2ms ± 0% 11.9ms ± 0% -2.38% (p=0.000 n=17+19)
JSONDecode-12 52.3ms ± 0% 53.3ms ± 0% +1.84% (p=0.000 n=19+20)
Mandelbrot200-12 3.69ms ± 0% 3.69ms ± 0% -0.19% (p=0.000 n=19+19)
GoParse-12 3.17ms ± 1% 3.19ms ± 1% +0.61% (p=0.000 n=20+20)
RegexpMatchEasy0_32-12 73.7ns ± 0% 73.2ns ± 1% -0.66% (p=0.000 n=17+20)
RegexpMatchEasy0_1K-12 238ns ± 0% 239ns ± 0% +0.32% (p=0.000 n=17+16)
RegexpMatchEasy1_32-12 69.1ns ± 1% 69.2ns ± 1% ~ (p=0.669 n=19+13)
RegexpMatchEasy1_1K-12 365ns ± 1% 367ns ± 1% +0.49% (p=0.000 n=19+19)
RegexpMatchMedium_32-12 104ns ± 1% 105ns ± 1% +1.33% (p=0.000 n=16+20)
RegexpMatchMedium_1K-12 33.6µs ± 3% 34.1µs ± 4% +1.67% (p=0.001 n=20+20)
RegexpMatchHard_32-12 1.67µs ± 1% 1.62µs ± 1% -2.78% (p=0.000 n=18+17)
RegexpMatchHard_1K-12 50.3µs ± 2% 48.7µs ± 1% -3.09% (p=0.000 n=19+18)
Revcomp-12 384ms ± 0% 386ms ± 0% +0.59% (p=0.000 n=19+19)
Template-12 61.1ms ± 1% 60.5ms ± 1% -1.02% (p=0.000 n=19+20)
TimeParse-12 307ns ± 0% 303ns ± 1% -1.23% (p=0.000 n=19+15)
TimeFormat-12 323ns ± 0% 323ns ± 0% -0.12% (p=0.011 n=15+20)
[Geo mean] 47.1µs 47.0µs -0.20%
https://perf.golang.org/search?q=upload:20171030.4
It slightly improve the performance the x/benchmarks:
name old time/op new time/op delta
Garbage/benchmem-MB=1024-12 2.29ms ± 3% 2.22ms ± 2% -2.97% (p=0.000 n=18+18)
Garbage/benchmem-MB=64-12 2.24ms ± 2% 2.21ms ± 2% -1.64% (p=0.000 n=18+18)
HTTP-12 12.6µs ± 1% 12.6µs ± 1% ~ (p=0.690 n=19+17)
JSON-12 11.3ms ± 2% 11.3ms ± 1% ~ (p=0.163 n=17+18)
and fixes some of the heap size bloat caused by the previous commit:
name old peak-RSS-bytes new peak-RSS-bytes delta
Garbage/benchmem-MB=1024-12 1.88G ± 2% 1.77G ± 2% -5.52% (p=0.000 n=20+18)
Garbage/benchmem-MB=64-12 248M ± 8% 226M ± 5% -8.93% (p=0.000 n=20+20)
HTTP-12 47.0M ±27% 47.2M ±12% ~ (p=0.512 n=20+20)
JSON-12 206M ±11% 206M ±10% ~ (p=0.841 n=20+20)
https://perf.golang.org/search?q=upload:20171030.5
Combined with the change to add a soft goal in the previous commit,
the achieves a decent performance improvement on the garbage
benchmark:
name old time/op new time/op delta
Garbage/benchmem-MB=1024-12 2.40ms ± 4% 2.22ms ± 2% -7.40% (p=0.000 n=19+18)
Garbage/benchmem-MB=64-12 2.23ms ± 1% 2.21ms ± 2% -1.06% (p=0.000 n=19+18)
HTTP-12 12.5µs ± 1% 12.6µs ± 1% ~ (p=0.330 n=20+17)
JSON-12 11.1ms ± 1% 11.3ms ± 1% +1.87% (p=0.000 n=16+18)
https://perf.golang.org/search?q=upload:20171030.6
Change-Id: If04ddb57e1e58ef2fb9eec54c290eb4ae4bea121
Reviewed-on: https://go-review.googlesource.com/59971
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
Currently, GC pacing is based on a single hard heap limit computed
based on GOGC. In order to achieve this hard limit, assist pacing
makes the conservative assumption that the entire heap is live.
However, in the steady state (with GOGC=100), only half of the heap is
live. As a result, the garbage collector works twice as hard as
necessary and finishes half way between the trigger and the goal.
Since this is a stable state for the trigger controller, this repeats
from cycle to cycle. Matters are even worse if GOGC is higher. For
example, if GOGC=200, only a third of the heap is live in steady
state, so the GC will work three times harder than necessary and
finish only a third of the way between the trigger and the goal.
Since this causes the garbage collector to consume ~50% of the
available CPU during marking instead of the intended 25%, about 25% of
the CPU goes to mutator assists. This high mutator assist cost causes
high mutator latency variability.
This commit improves the situation by separating the heap goal into
two goals: a soft goal and a hard goal. The soft goal is set based on
GOGC, just like the current goal is, and the hard goal is set at a 10%
larger heap than the soft goal. Prior to the soft goal, assist pacing
assumes the heap is in steady state (e.g., only half of it is live).
Between the soft goal and the hard goal, assist pacing switches to the
current conservative assumption that the entire heap is live.
In benchmarks, this nearly eliminates mutator assists. However, since
background marking is fixed at 25% CPU, this causes the trigger
controller to saturate, which leads to somewhat higher variability in
heap size. The next commit will address this.
The lower CPU usage of course leads to longer mark cycles, though
really it means the mark cycles are as long as they should have been
in the first place. This does, however, lead to two potential
down-sides compared to the current pacing policy: 1. the total
overhead of the write barrier is higher because it's enabled more of
the time and 2. the heap size may be larger because there's more
floating garbage. We addressed 1 by significantly improving the
performance of the write barrier in the preceding commits. 2 can be
demonstrated in intense GC benchmarks, but doesn't seem to be a
problem in any real applications.
Updates #14951.
Updates #14812 (fixes?).
Fixes#18534.
This has no significant effect on the throughput of the
github.com/dr2chase/bent benchmarks-50.
This has little overall throughput effect on the go1 benchmarks:
name old time/op new time/op delta
BinaryTree17-12 2.41s ± 0% 2.40s ± 0% -0.22% (p=0.007 n=20+18)
Fannkuch11-12 2.95s ± 0% 2.95s ± 0% +0.07% (p=0.003 n=17+18)
FmtFprintfEmpty-12 41.7ns ± 3% 42.2ns ± 0% +1.17% (p=0.002 n=20+15)
FmtFprintfString-12 66.5ns ± 0% 67.9ns ± 2% +2.16% (p=0.000 n=16+20)
FmtFprintfInt-12 77.6ns ± 2% 75.6ns ± 3% -2.55% (p=0.000 n=19+19)
FmtFprintfIntInt-12 124ns ± 1% 123ns ± 1% -0.98% (p=0.000 n=18+17)
FmtFprintfPrefixedInt-12 151ns ± 1% 148ns ± 1% -1.75% (p=0.000 n=19+20)
FmtFprintfFloat-12 210ns ± 1% 212ns ± 0% +0.75% (p=0.000 n=19+16)
FmtManyArgs-12 501ns ± 1% 499ns ± 1% -0.30% (p=0.041 n=17+19)
GobDecode-12 6.50ms ± 1% 6.49ms ± 1% ~ (p=0.234 n=19+19)
GobEncode-12 5.43ms ± 0% 5.47ms ± 0% +0.75% (p=0.000 n=20+19)
Gzip-12 216ms ± 1% 220ms ± 1% +1.71% (p=0.000 n=19+20)
Gunzip-12 38.6ms ± 0% 38.8ms ± 0% +0.66% (p=0.000 n=18+19)
HTTPClientServer-12 78.1µs ± 1% 78.5µs ± 1% +0.49% (p=0.035 n=20+20)
JSONEncode-12 12.1ms ± 0% 12.2ms ± 0% +1.05% (p=0.000 n=18+17)
JSONDecode-12 53.0ms ± 0% 52.3ms ± 0% -1.27% (p=0.000 n=19+19)
Mandelbrot200-12 3.74ms ± 0% 3.69ms ± 0% -1.17% (p=0.000 n=18+19)
GoParse-12 3.17ms ± 1% 3.17ms ± 1% ~ (p=0.569 n=19+20)
RegexpMatchEasy0_32-12 73.2ns ± 1% 73.7ns ± 0% +0.76% (p=0.000 n=18+17)
RegexpMatchEasy0_1K-12 239ns ± 0% 238ns ± 0% -0.27% (p=0.000 n=13+17)
RegexpMatchEasy1_32-12 69.0ns ± 2% 69.1ns ± 1% ~ (p=0.404 n=19+19)
RegexpMatchEasy1_1K-12 367ns ± 1% 365ns ± 1% -0.60% (p=0.000 n=19+19)
RegexpMatchMedium_32-12 105ns ± 1% 104ns ± 1% -1.24% (p=0.000 n=19+16)
RegexpMatchMedium_1K-12 34.1µs ± 2% 33.6µs ± 3% -1.60% (p=0.000 n=20+20)
RegexpMatchHard_32-12 1.62µs ± 1% 1.67µs ± 1% +2.75% (p=0.000 n=18+18)
RegexpMatchHard_1K-12 48.8µs ± 1% 50.3µs ± 2% +3.07% (p=0.000 n=20+19)
Revcomp-12 386ms ± 0% 384ms ± 0% -0.57% (p=0.000 n=20+19)
Template-12 59.9ms ± 1% 61.1ms ± 1% +2.01% (p=0.000 n=20+19)
TimeParse-12 301ns ± 2% 307ns ± 0% +2.11% (p=0.000 n=20+19)
TimeFormat-12 323ns ± 0% 323ns ± 0% ~ (all samples are equal)
[Geo mean] 47.0µs 47.1µs +0.23%
https://perf.golang.org/search?q=upload:20171030.1
Likewise, the throughput effect on the x/benchmarks is minimal (and
reasonably positive on the garbage benchmark with a large heap):
name old time/op new time/op delta
Garbage/benchmem-MB=1024-12 2.40ms ± 4% 2.29ms ± 3% -4.57% (p=0.000 n=19+18)
Garbage/benchmem-MB=64-12 2.23ms ± 1% 2.24ms ± 2% +0.59% (p=0.016 n=19+18)
HTTP-12 12.5µs ± 1% 12.6µs ± 1% ~ (p=0.326 n=20+19)
JSON-12 11.1ms ± 1% 11.3ms ± 2% +2.15% (p=0.000 n=16+17)
It does increase the heap size of the garbage benchmarks, but seems to
have relatively little impact on more realistic programs. Also, we'll
gain some of this back with the next commit.
name old peak-RSS-bytes new peak-RSS-bytes delta
Garbage/benchmem-MB=1024-12 1.21G ± 1% 1.88G ± 2% +55.59% (p=0.000 n=19+20)
Garbage/benchmem-MB=64-12 168M ± 3% 248M ± 8% +48.08% (p=0.000 n=18+20)
HTTP-12 45.6M ± 9% 47.0M ±27% ~ (p=0.925 n=20+20)
JSON-12 193M ±11% 206M ±11% +7.06% (p=0.001 n=20+20)
https://perf.golang.org/search?q=upload:20171030.2
Change-Id: Ic78904135f832b4d64056cbe734ab979f5ad9736
Reviewed-on: https://go-review.googlesource.com/59970
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
The compiler's instrumentation pass has some out-of-date comments
about the write barrier and some confusing comments about
typedslicecopy. Update these comments and add a comment to
typedslicecopy explaining why it's manually instrumented while none of
the other operations are.
Change-Id: I024e5361d53f1c3c122db0c85155368a30cabd6b
Reviewed-on: https://go-review.googlesource.com/74430
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
The content-based staleness code means that
go run -gcflags=-l helloworld.go
recompiles all of helloworld.go's dependencies with -gcflags=-l,
whereas before it would have assumed installed packages were
up-to-date. In this test, that means every race iteration rebuilds
the runtime and maybe a few other packages. Instead, install them
to a temporary location for reuse.
This speeds the test from 17s to 9s on my MacBook Pro.
Change-Id: Ied136ce72650261083bb19cc7dee38dac0ad05ca
Reviewed-on: https://go-review.googlesource.com/73992
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This cuts 23 seconds from all.bash on my MacBook Pro.
Change-Id: Ibc4d7c01660b9e9ebd088dd55ba993f0d7ec6aa3
Reviewed-on: https://go-review.googlesource.com/73991
Reviewed-by: Ian Lance Taylor <iant@golang.org>
If the go install doesn't use the same flags as the main build
it can overwrite the installed standard library, leading to
flakiness and slow future tests.
Force uses of 'go install' etc to propagate $GO_GCFLAGS
or disable them entirely, to avoid problems.
As I understand it, the main place this happens is the ssacheck builder.
If there are other uses that need to run some of the now-disabled
tests we can reenable fixed tests in followup CLs.
Change-Id: Ib860a253539f402f8a96a3c00ec34f0bbf137c9a
Reviewed-on: https://go-review.googlesource.com/74470
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Memory accesses on z are at least as ordered as they are on AMD64.
Change-Id: Ia515430e571ebd07e9314de05c54dc992ab76b95
Reviewed-on: https://go-review.googlesource.com/74010
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Munday <mike.munday@ibm.com>
This modifies bulkBarrierPreWrite to use the buffered write barrier
instead of the eager write barrier. This reduces the number of system
stack switches and sanity checks by a factor of the buffer size
(currently 256). This affects both typedmemmove and typedmemclr.
Since this is purely a runtime change, it applies to all arches
(unlike the pointer write barrier).
name old time/op new time/op delta
BulkWriteBarrier-12 7.33ns ± 6% 4.46ns ± 9% -39.10% (p=0.000 n=20+19)
Updates #22460.
Change-Id: I6a686a63bbf08be02b9b97250e37163c5a90cdd8
Reviewed-on: https://go-review.googlesource.com/73832
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
Currently, typedslicecopy meticulously performs a typedmemmove on
every element of the slice. This probably used to be necessary because
we only had an individual element's type, but now we use the heap
bitmap, so we only need to know whether the type has any pointers and
how big it is. Hence, this CL rewrites typedslicecopy to simply
perform one bulk barrier and one memmove.
This also has a side-effect of eliminating two unnecessary write
barriers per slice element that were coming from updates to dstp and
srcp, which were stored in the parent stack frame. However, most of
the win comes from eliminating the loops.
name old time/op new time/op delta
BulkWriteBarrier-12 7.83ns ±10% 7.33ns ± 6% -6.45% (p=0.000 n=20+20)
Updates #22460.
Change-Id: Id3450e9f36cc8e0892f268319b136f0d8f5464b8
Reviewed-on: https://go-review.googlesource.com/73831
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
This adds a benchmark of typedslicecopy and its bulk write barriers.
For #22460.
Change-Id: I439ca3b130bb22944468095f8f18b464e5bb43ca
Reviewed-on: https://go-review.googlesource.com/74051
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
This implements runtime support for buffered write barriers on amd64.
The buffered write barrier has a fast path that simply enqueues
pointers in a per-P buffer. Unlike the current write barrier, this
fast path is *not* a normal Go call and does not require the compiler
to spill general-purpose registers or put arguments on the stack. When
the buffer fills up, the write barrier takes the slow path, which
spills all general purpose registers and flushes the buffer. We don't
allow safe-points or stack splits while this frame is active, so it
doesn't matter that we have no type information for the spilled
registers in this frame.
One minor complication is cgocheck=2 mode, which uses the write
barrier to detect Go pointers being written to non-Go memory. We
obviously can't buffer this, so instead we set the buffer to its
minimum size, forcing the write barrier into the slow path on every
call. For this specific case, we pass additional information as
arguments to the flush function. This also requires enabling the cgo
write barrier slightly later during runtime initialization, after Ps
(and the per-P write barrier buffers) have been initialized.
The code in this CL is not yet active. The next CL will modify the
compiler to generate calls to the new write barrier.
This reduces the average cost of the write barrier by roughly a factor
of 4, which will pay for the cost of having it enabled more of the
time after we make the GC pacer less aggressive. (Benchmarks will be
in the next CL.)
Updates #14951.
Updates #22460.
Change-Id: I396b5b0e2c5e5c4acfd761a3235fd15abadc6cb1
Reviewed-on: https://go-review.googlesource.com/73711
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
Currently systemstack always calls its argument, even if we're already
on the system stack. Unfortunately, traceback with _TraceJump stops at
the first systemstack it sees, which often cuts off runtime stacks
early in profiles.
Fix this by performing a tail call if we're already on the system
stack. This eliminates it from the traceback entirely, so it won't
stop prematurely (or all get mushed into a single node in the profile
graph).
Change-Id: Ibc69e8765e899f8d3806078517b8c7314da196f4
Reviewed-on: https://go-review.googlesource.com/74050
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
Errors occur in runtime test testCgoPprofPIE when the test
is built by passing -pie to the external linker with code
that was not built as PIC. This occurs on ppc64le because
non-PIC is the default, and fails only on newer distros
where the address range used for programs is high enough
to cause relocation overflow. This test should be built
with -buildmode=pie since that correctly generates PIC
with -pie.
Related issues are #21954 and #22126.
Updates #22459
Change-Id: Ib641440bc9f94ad2b97efcda14a4b482647be8f7
Reviewed-on: https://go-review.googlesource.com/73970
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
recordspan has two remaining write barriers from writing to the
pointer to the backing store of h.allspans. However, h.allspans is
always backed by off-heap memory, so let the compiler know this.
Unfortunately, this isn't quite as clean as most go:notinheap uses
because we can't directly name the backing store of a slice, but we
can get it done with some judicious casting.
For #22460.
Change-Id: I296f92fa41cf2cb6ae572b35749af23967533877
Reviewed-on: https://go-review.googlesource.com/73414
Reviewed-by: Rick Hudson <rlh@golang.org>
We're about to start tracking nowritebarrierrec through systemstack
calls, which detects that we're calling markroot (which has write
barriers) from gchelper, which is called from the scheduler during STW
apparently without a P.
But it turns out that func helpgc, which wakes up blocked Ms to run
gchelper, installs a P for gchelper to use. This means there *is* a P
when gchelper runs, so it is allowed to have write barriers. Tell the
compiler this by marking gchelper go:yeswritebarrierrec. Also,
document the call to gchelper so I don't have to spend another half a
day puzzling over how on earth this could possibly work before
discovering the spooky action-at-a-distance in helpgc.
Updates #22384.
For #22460.
Change-Id: I7394c9b4871745575f87a2d4fbbc5b8e54d669f7
Reviewed-on: https://go-review.googlesource.com/72772
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
We're about to start tracking nowritebarrierrec through systemstack
calls, which will reveal write barriers in persistentalloc prohibited
by various callers.
The pointers manipulated by persistentalloc are always to off-heap
memory, so this removes these write barriers statically by introducing
a new go:notinheap type to represent generic off-heap memory.
Updates #22384.
For #22460.
Change-Id: Id449d9ebf145b14d55476a833e7f076b0d261d57
Reviewed-on: https://go-review.googlesource.com/72771
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
We're about to start tracking nowritebarrierrec through systemstack
calls, which will reveal write barriers in startpanic_m prohibited by
various callers.
We actually can allow write barriers here because the write barrier is
a no-op when we're panicking. Let the compiler know.
Updates #22384.
For #22460.
Change-Id: Ifb3a38d3dd9a4125c278c3680f8648f987a5b0b8
Reviewed-on: https://go-review.googlesource.com/72770
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
Currently most of these are marked go:nowritebarrier as a hint, but
it's actually important that these not invoke write barriers
recursively. The danger is that some gcWork method would invoke the
write barrier while the gcWork is in an inconsistent state and that
the write barrier would in turn invoke some other gcWork method, which
would crash or permanently corrupt the gcWork. Simply marking the
write barrier itself as go:nowritebarrierrec isn't sufficient to
prevent this if the write barrier doesn't use the outer method.
Thankfully, this doesn't cause any build failures, so we were getting
this right. :)
For #22460.
Change-Id: I35a7292a584200eb35a49507cd3fe359ba2206f6
Reviewed-on: https://go-review.googlesource.com/72554
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
Currently, newstack and gogo have write barriers for maintaining the
context register saved in g.sched.ctxt. This is troublesome, because
newstack can be called from go:nowritebarrierrec places that can't
allow write barriers. It happens to be benign because g.sched.ctxt
will always be nil on entry to newstack *and* it so happens the
incoming ctxt will also always be nil in these contexts (I
think/hope), but this is playing with fire. It's also desirable to
mark newstack go:nowritebarrierrec to prevent any other, non-benign
write barriers from creeping in, but we can't do that right now
because of this one write barrier.
Fix all of this by observing that g.sched.ctxt is really just a saved
live pointer register. Hence, we can shade it when we scan g's stack
and otherwise move it back and forth between the actual context
register and g.sched.ctxt without write barriers. This means we can
save it in morestack along with all of the other g.sched, eliminate
the save from newstack along with its troublesome write barrier, and
eliminate the shenanigans in gogo to invoke the write barrier when
restoring it.
Once we've done all of this, we can mark newstack
go:nowritebarrierrec.
Fixes#22385.
For #22460.
Change-Id: I43c24958e3f6785b53c1350e1e83c2844e0d1522
Reviewed-on: https://go-review.googlesource.com/72553
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
TestParallelRWMutexReaders has a non-preemptible loop in it that can
deadlock if GC triggers. "Fix" it like we've fixed similar tests.
Updates #10958.
Change-Id: I13618f522f5ef0c864e7171ad2f655edececacd7
Reviewed-on: https://go-review.googlesource.com/73710
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Otherwise low-res timers cause problems at call sites that expect to
be able to use 0 as meaning "no time set" and therefore expect that
nanotime never returns 0 itself. For example, sched.lastpoll == 0
means no last poll.
Fixes#22394.
Change-Id: Iea28acfddfff6f46bc90f041ec173e0fea591285
Reviewed-on: https://go-review.googlesource.com/73410
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
The BigEndian constant is only used in boolean context so assign it
boolean constants.
Change-Id: If19d61dd71cdfbffede1d98b401f11e6535fba59
Reviewed-on: https://go-review.googlesource.com/73270
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Make netpollopen return what Windows GetLastError API returns.
It is probably copy / paste error from long time ago.
Change-Id: I28f78718c15fef3e8b5f5d11a259533d7e9c6185
Reviewed-on: https://go-review.googlesource.com/72592
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Increasing the map size with the benchmark iteration count
introduced non-linearities and made benchmark runs slow when
increasing benchtime.
Rework the benchmark to use a map size independent of the
iteration count and instead re-fill it when it becomes empty.
Fixes#21546
Change-Id: Iafb6eb225e81830263f30b3aba0d449c361aec32
Reviewed-on: https://go-review.googlesource.com/57650
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
On systems that use kqueue, we always register descriptors for both
EVFILT_READ and EVFILT_WRITE. On at least FreeBSD and OpenBSD, when
the write end of a pipe is registered for EVFILT_READ and EVFILT_WRITE
events, and the read end of the pipe is closed, kqueue reports an
EVFILT_READ event with EV_EOF set, but does not report an EVFILT_WRITE
event. Since the write to the pipe is waiting for an EVFILT_WRITE
event, closing the read end of a pipe can cause the write end to hang
rather than attempt another write which will fail with EPIPE.
Fix this by treating EVFILT_READ with EV_EOF set as making both reads
and writes ready to proceed.
The real test for this is in CL 71770, which tests using various
timeouts with pipes.
Updates #22114
Change-Id: Ib23fbaaddbccd8eee77bdf18f27a7f0aa50e2742
Reviewed-on: https://go-review.googlesource.com/71973
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Currently mmap returns an unsafe.Pointer that encodes OS errors as
values less than 4096. In practice this is okay, but it borders on
being really unsafe: for example, the value has to be checked
immediately after return and if stack copying were ever to observe
such a value, it would panic. It's also not remotely idiomatic.
Fix this by making mmap return a separate pointer value and error,
like a normal Go function.
Updates #22218.
Change-Id: Iefd965095ffc82cc91118872753a5d39d785c3a6
Reviewed-on: https://go-review.googlesource.com/71270
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Fixes Darwin 386 build. It turns out that the Darwin pthread_create
function saves the SSE registers, and therefore requires an aligned stack.
This worked before https://golang.org/cl/70530 because the stack sizes
were chosen to leave the stack aligned.
Change-Id: I911a9e8dcde4e41e595d5ef9b9a1ca733e154de6
Reviewed-on: https://go-review.googlesource.com/71432
Reviewed-by: Robert Griesemer <gri@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
CL 46037 and CL 46038 implemented termination of
locked OS threads when the goroutine exits.
However, this behavior leads to crashes of Go programs
using runtime.LockOSThread on Plan 9. This is notably
the case of the os/exec and net packages.
This change disables termination of locked OS threads
on Plan 9.
Updates #22227.
Change-Id: If9fa241bff1c0b68e7e9e321e06e5203b3923212
Reviewed-on: https://go-review.googlesource.com/71230
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
CL 46033 added a "template thread" mechanism to
allow creation of thread with a known-good state
from a thread of unknown state.
However, we are experiencing issues on Plan 9
with programs using the os/exec and net package.
These package are relying on runtime.LockOSThread.
Updates #22227.
Change-Id: I85b71580a41df9fe8b24bd8623c064b6773288b0
Reviewed-on: https://go-review.googlesource.com/70231
Run-TryBot: David du Colombier <0intro@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Unify the 386 entry point code as much as possible.
The main function could not be unified because on Windows 386 it is
called _main. Putting main in asm_386.s caused multiple definition
errors when using the external linker.
Add the _lib entry point to various operating systems. A future CL
will enable c-archive/c-shared mode for those targets.
Fix _rt0_386_windows_lib_go--it was passing arguments as though it
were amd64.
Change-Id: Ic73f1c95cdbcbea87f633f4a29bbc218a5db4f58
Reviewed-on: https://go-review.googlesource.com/70530
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Use TEXT pseudo-instruction to adjust SP instead of a SUB instruction
so that the assembler knows how to fill in the pcsp table and the frame
description entry correctly.
Updates #21569
Change-Id: I436c840b2af99bbb3042ecd38a7d7c1ab4d7372a
Reviewed-on: https://go-review.googlesource.com/70937
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The code was commented out by https://golang.org/cl/13234050 in 2013.
Let's just remove it.
Change-Id: I46ae1f07386719e991458e782d236214c40bdce1
Reviewed-on: https://go-review.googlesource.com/70770
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
STREX does not permit using the same register for the value to store
and the place where the result is returned. Also the code was wrong
anyhow if the first store failed.
Fixes#22248
Change-Id: I96013497410058514ffcb771c76c86faa1ec559b
Reviewed-on: https://go-review.googlesource.com/70911
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Currently only a single P can run a fractional mark worker at a time.
This doesn't let us spread out the load, so it gets concentrated on
whatever unlucky P picks up the token to run a fractional worker. This
can significantly delay goroutines on that P.
This commit changes this scheduling rule so each P separately
schedules fractional workers. This can significantly reduce the load
on any individual P and allows workers to self-preempt earlier. It
does have the downside that it's possible for all Ps to be in
fractional workers simultaneously (an effect STW).
Updates #21698.
Change-Id: Ia1e300c422043fa62bb4e3dd23c6232d81e4419c
Reviewed-on: https://go-review.googlesource.com/68574
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
Currently fractional workers run until preempted by the scheduler,
which means they typically run for 20ms. During this time, all other
goroutines on that P are blocked, which can introduce significant
latency variance.
This modifies fractional workers to self-preempt shortly after
achieving the fractional utilization goal. In practice this means they
preempt much sooner, and the scale of their preemption is on the order
of how often the user goroutine block (so, if the application is
compute-bound, the fractional workers will also run for long times,
but if the application blocks frequently, the fractional workers will
also preempt quickly).
Fixes#21698.
Updates #18534.
Change-Id: I03a5ab195dae93154a46c32083c4bb52415d2017
Reviewed-on: https://go-review.googlesource.com/68573
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
We haven't used non-zero gcForcePreemptNS for ages. Remove it and
declutter the code.
Change-Id: Id5cc62f526d21ca394d2b6ca17d34a72959535da
Reviewed-on: https://go-review.googlesource.com/68572
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
When GOMAXPROCS is not small, fractional workers don't add much to
throughput, but they do add to the latency of individual goroutines.
In this case, it makes sense to just use dedicated workers, even if we
can't exactly hit the 25% CPU goal with dedicated workers.
This implements this logic by computing the number of dedicated mark
workers that will us closest to the 25% target. We only fall back to
fractional workers if that would be more than 30% off of the target
(less than 17.5% or more than 32.5%, which in practice happens for
GOMAXPROCS <= 3 and GOMAXPROCS == 6).
Updates #21698.
Change-Id: I484063adeeaa1190200e4ef210193a20e635d552
Reviewed-on: https://go-review.googlesource.com/68571
Reviewed-by: Rick Hudson <rlh@golang.org>
Currently these are the same constant, but are separate concepts.
Split them into two constants for easier experimentation and better
documentation.
Change-Id: I121854d4fd1a4a827f727c8e5153160c24aacda7
Reviewed-on: https://go-review.googlesource.com/68570
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
This change adds support for accelerating time.Now by using
the __vdso_clock_gettime fast-path via the vDSO on linux/386
if it is available.
When the vDSO path to the clocks is available, it is typically
5x-10x faster than the syscall path (see benchmark extract
below). Two such calls are made for each time.Now() call
on most platforms as of go 1.9.
- Add vdso_linux_386.go, containing the ELF32 definitions
for use by vdso_linux.go, the maximum array size, and
the symbols to be located in the vDSO.
- Modify runtime.walltime and runtime.nanotime to check for
and use the vDSO fast-path if available, or fall back to
the existing syscall path.
- Reduce the stack reservations for runtime.walltime and
runtime.monotime from 32 to 16 bytes. It appears the syscall
path actually only needed 8 bytes, but 16 is now needed to
cover the syscall and vDSO paths.
- Remove clearing DX from the syscall paths as clock_gettime
only takes 2 args (BX, CX in syscall calling convention),
so there should be no need to clear DX.
The included BenchmarkTimeNow was run with -cpu=1 -count=20
on an "Intel(R) Celeron(R) CPU J1900 @ 1.99GHz", comparing
released go 1.9.1 vs this change. This shows a gain in
performance on linux/386 (6.89x), and that no regression
occurred on linux/amd64 due to this change.
Kernel: linux/i686, GOOS=linux GOARCH=386
name old time/op new time/op delta
TimeNow 978ns ± 0% 142ns ± 0% -85.48% (p=0.000 n=16+20)
Kernel: linux/x86_64, GOOS=linux GOARCH=amd64
name old time/op new time/op delta
TimeNow 125ns ± 0% 125ns ± 0% ~ (all equal)
Gains are more dramatic in virtualized environments,
presumably due to the overhead of virtualizing the syscall.
Fixes#22190
Change-Id: I2f83ce60cb1b8b310c9ced0706bb463c1b3aedf8
Reviewed-on: https://go-review.googlesource.com/69390
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This is a preparation step for adding vDSO support on linux/386.
This change relocates the elf64 and amd64 specifics from
vdso_linux.go to a new vdso_linux_amd64.go.
This should enable vdso_linux.go to be used for vDSO
support on linux architectures other than amd64.
- Relocate the elf64X structure definitions appropriate to amd64,
and change their names to elfX so that the code in vdso_linux.go
is ELFnn-agnostic.
- Relocate the sym_keys and corresponding __vdso_* variables
appropriate to amd64.
- Provide an amd64-specific constant for the maximum byte size of
an array, and use this in vdso_linux.go to compute constants for
sizing the elf structure arrays traversed in the loaded vDSO.
Change-Id: I1edb4e4ec9f2d79b7533aa95fbd09f771fa4edef
Reviewed-on: https://go-review.googlesource.com/69391
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Currently we look to see if the main.main symbol address is in the
module data text range. This requires access to the main.main
symbol, which usually the runtime has, but does not when building
a plugin.
To avoid a dynamic relocation to main.main (which I haven't worked
out how to have the linker generate on darwin), stop using the
symbol. Instead record a boolean in the moduledata if the module
has the main function.
Fixes#22175
Change-Id: If313a118f17ab499d0a760bbc2519771ed654530
Reviewed-on: https://go-review.googlesource.com/69370
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The .debug_aranges section is an odd vestige of DWARF, since its
contents are easy and efficient for a debugger to reconstruct from the
attributes of the top-level compilation unit DIEs. Neither GCC nor
clang emit it by default these days. GDB and Delve ignore it entirely.
LLDB will use it if present, but is happy to construct the index from
the compilation unit attributes (and, indeed, a remarkable variety of
other ways if those aren't available either).
We're about to split up the compilation units by package, which means
they'll have discontiguous PC ranges, which is going to make
.debug_aranges harder to construct (and larger).
Rather than try to maintain this essentially unused code, let's
simplify things and remove it.
Change-Id: I8e0ccc033b583b5b8908cbb2c879b2f2d5f9a50b
Reviewed-on: https://go-review.googlesource.com/69972
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
The alternative signal stack doesn't work on ios, so the setup of
the alternative stack was skipped. The corresponding unminitSignals
was effectively a no-op on ios until CL 70130. Skip unminitSignals
on ios to restore the previous behaviour.
For the ios builders.
Change-Id: I5692ca7f5997e6b9d10cc5f2383a5a37c42b133c
Reviewed-on: https://go-review.googlesource.com/70270
Run-TryBot: Elias Naur <elias.naur@gmail.com>
Reviewed-by: Austin Clements <austin@google.com>
CL 69292 unified the amd64 entry-points, but Dragonfly doesn't follow
the same entry-point argument conventions as most other amd64
platforms. Fix the Dragonfly entry point.
Change-Id: I0f84e2e4101ce68217af185ee9baaf455b8b6dad
Reviewed-on: https://go-review.googlesource.com/70212
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Since CL 46037, the runtime is crashing after calling
exitThread on Plan 9.
The exitThread function shouldn't be called on
Plan 9, because the system manages thread stacks.
Fixes#22221.
Change-Id: I5d61c9660a87dc27e4cfcb3ca3ddcb4b752f2397
Reviewed-on: https://go-review.googlesource.com/70190
Run-TryBot: David du Colombier <0intro@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
