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Commit Graph

833 Commits

Author SHA1 Message Date
Michael Hudson-Doyle
658a338f78 cmd/internal/ld, runtime: halve tlsoffset on ELF/intel
For OSes that use elf on intel, 2*Ptrsize bytes are reserved for TLS.
But only one pointer (g) has been stored in the TLS for a while now.
So we can set it to just Ptrsize, which happily matches what happens
when externally linking.

Fixes #9913

Change-Id: Ic816369d3a55a8cdcc23be349b1a1791d53f5f81
Reviewed-on: https://go-review.googlesource.com/6584
Run-TryBot: Minux Ma <minux@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-03-05 01:23:29 +00:00
Rick Hudson
122384e489 runtime: Remove boundary bit logic.
This is an experiment to see if removing the boundary bit logic will
lead to fewer cache misses and improved performance. Instead of using
boundary bits we use the span information to get element size and use
some bit whacking to get the boundary without having to touch the
random heap bits which cause cache misses.

Furthermore once the boundary bit is removed we can either use that
bit for a simpler checkmark routine or we can reduce the number of
bits in the GC bitmap to 2 bits per pointer sized work. For example
the 2 bits at the boundary can be used for marking and pointer/scalar
differentiation. Since we don't need the mark bit except at the
boundary nibble of the object other nibbles can use this bit
as a noscan bit to indicate that there are no more pointers in
the object.

Currently the changed included in this CL slows down the garbage
benchmark. With the boundary bits garbage gives 5.78 and without
(this CL) it gives 5.88 which is a 2% slowdown.

Change-Id: Id68f831ad668176f7dc9f7b57b339e4ebb6dc4c2
Reviewed-on: https://go-review.googlesource.com/6665
Reviewed-by: Austin Clements <austin@google.com>
2015-03-04 20:55:55 +00:00
Russ Cox
9feb24f3ed runtime: use multiply instead of divide in heapBitsForObject
These benchmarks show the effect of the combination of this change
and Rick's pending CL 6665. Code with interior pointers is helped
much more than code without, but even code without doesn't suffer
too badly.

benchmark                          old ns/op      new ns/op      delta
BenchmarkBinaryTree17              6989407768     6851728175     -1.97%
BenchmarkFannkuch11                4416250775     4405762558     -0.24%
BenchmarkFmtFprintfEmpty           134            130            -2.99%
BenchmarkFmtFprintfString          491            402            -18.13%
BenchmarkFmtFprintfInt             430            420            -2.33%
BenchmarkFmtFprintfIntInt          748            663            -11.36%
BenchmarkFmtFprintfPrefixedInt     602            534            -11.30%
BenchmarkFmtFprintfFloat           728            699            -3.98%
BenchmarkFmtManyArgs               2528           2507           -0.83%
BenchmarkGobDecode                 17448191       17749756       +1.73%
BenchmarkGobEncode                 14579824       14370183       -1.44%
BenchmarkGzip                      656489990      652669348      -0.58%
BenchmarkGunzip                    141254147      141099278      -0.11%
BenchmarkHTTPClientServer          94111          93738          -0.40%
BenchmarkJSONEncode                36305013       36696440       +1.08%
BenchmarkJSONDecode                124652000      128176454      +2.83%
BenchmarkMandelbrot200             6009333        5997093        -0.20%
BenchmarkGoParse                   7651583        7623494        -0.37%
BenchmarkRegexpMatchEasy0_32       213            213            +0.00%
BenchmarkRegexpMatchEasy0_1K       511            494            -3.33%
BenchmarkRegexpMatchEasy1_32       186            187            +0.54%
BenchmarkRegexpMatchEasy1_1K       1834           1827           -0.38%
BenchmarkRegexpMatchMedium_32      427            412            -3.51%
BenchmarkRegexpMatchMedium_1K      154841         153086         -1.13%
BenchmarkRegexpMatchHard_32        7473           7478           +0.07%
BenchmarkRegexpMatchHard_1K        233587         232272         -0.56%
BenchmarkRevcomp                   918797689      944528032      +2.80%
BenchmarkTemplate                  167665081      167773121      +0.06%
BenchmarkTimeParse                 631            636            +0.79%
BenchmarkTimeFormat                672            666            -0.89%

Change-Id: Ia923de3cdb3993b640fe0a02cbe2c7babc16f32c
Reviewed-on: https://go-review.googlesource.com/6782
Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
2015-03-04 17:46:47 +00:00
Matthew Dempsky
81d4072eb0 cmd/internal/gc, runtime: change growslice to use int instead of int64
Gc already calculates n as an int, so converting to int64 to call
growslice doesn't serve any purpose except to emit slightly larger
code on 32-bit platforms.  Passing n as an int shrinks godoc's text
segment by 8kB (9472633 => 9464133) when building for ARM.

Change-Id: Ief9492c21d01afcb624d3f2a484df741450b788d
Reviewed-on: https://go-review.googlesource.com/6231
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-03-04 17:17:17 +00:00
Dmitry Vyukov
b759e225f5 runtime: bound defer pools (try 2)
The unbounded list-based defer pool can grow infinitely.
This can happen if a goroutine routinely allocates a defer;
then blocks on one P; and then unblocked, scheduled and
frees the defer on another P.
The scenario was reported on golang-nuts list.

We've been here several times. Any unbounded local caches
are bad and grow to infinite size. This change introduces
central defer pool; local pools become fixed-size
with the only purpose of amortizing accesses to the
central pool.

Freedefer now executes on system stack to not consume
nosplit stack space.

Change-Id: I1a27695838409259d1586a0adfa9f92bccf7ceba
Reviewed-on: https://go-review.googlesource.com/3967
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Dmitry Vyukov <dvyukov@google.com>
2015-03-04 14:29:58 +00:00
Dmitry Vyukov
5ef145c809 runtime: bound sudog cache
The unbounded list-based sudog cache can grow infinitely.
This can happen if a goroutine is routinely blocked on one P
and then unblocked and scheduled on another P.
The scenario was reported on golang-nuts list.

We've been here several times. Any unbounded local caches
are bad and grow to infinite size. This change introduces
central sudog cache; local caches become fixed-size
with the only purpose of amortizing accesses to the
central cache.

The change required to move sudog cache from mcache to P,
because mcache is not scanned by GC.

Change-Id: I3bb7b14710354c026dcba28b3d3c8936a8db4e90
Reviewed-on: https://go-review.googlesource.com/3742
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Dmitry Vyukov <dvyukov@google.com>
2015-03-04 14:14:29 +00:00
David Crawshaw
ec7d8a6167 runtime: remove makeStringSlice
Change-Id: I38d716de9d5a9c1b868641262067d0456d52c86d
Reviewed-on: https://go-review.googlesource.com/6612
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-03-03 17:54:47 +00:00
Keith Randall
f584c05fcc runtime: Update open/close/read/write to return -1 on error.
Error detection code copied from syscall, where presumably
we actually do it right.

Note that we throw the errno away.  The runtime doesn't use it.

Fixes #10052

Change-Id: I8de77dda6bf287276b137646c26b84fa61554ec8
Reviewed-on: https://go-review.googlesource.com/6571
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
2015-03-03 17:46:36 +00:00
David Crawshaw
dac3f486ac runtime: remove unused getenv function
Change-Id: I49cda99f81b754e25fad1483de373f7d07d64808
Reviewed-on: https://go-review.googlesource.com/6452
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
2015-03-02 19:19:25 +00:00
Matthew Dempsky
5324cf2d45 runtime: change sigset_all and sigset_none into constants on OpenBSD
OpenBSD's sigprocmask system call passes the signal mask by value
rather than reference, so vars are unnecessary.  Additionally,
declaring "var sigset_all = ^sigset_none" means sigset_all won't be
initialized until runtime_init is called, but the first call to
newosproc happens before then.

I've witnessed Go processes on OpenBSD crash from receiving SIGWINCH
on the newly created OS thread before it finished initializing.

Change-Id: I16995e7e466d5e7e50bcaa7d9490173789a0b4cc
Reviewed-on: https://go-review.googlesource.com/6440
Reviewed-by: Mikio Hara <mikioh.mikioh@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-03-02 08:30:39 +00:00
Dmitry Vyukov
fcc164d783 runtime: cleanup chan code
Move type definitions from chan1.go to chan.go and select.go.
Remove underscores from names.
Make c.buf unsafe.Pointer instead of *uint8.

Change-Id: I75cf8385bdb9f79eb5a7f7ad319495abbacbe942
Reviewed-on: https://go-review.googlesource.com/4900
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Dmitry Vyukov <dvyukov@google.com>
2015-03-02 08:09:49 +00:00
Russ Cox
dd82d5e728 runtime: fix traceback of crash before LR is stored
This fixes runtime's TestBreakpoint on ppc64:
the Breakpoint frame was not showing up in the trace.

It seems like f.frame should be either the frame size
including the saved LR (if any) or the frame size
not including the saved LR.

On ppc64, f.frame is the frame size not including the saved LR.

On arm, f.frame is the frame size not including the saved LR,
except when that's -4, f.frame is 0 instead.

The code here in the runtime expects that f.frame is the frame
size including the saved LR.

Since all three disagree and nothing else uses f.frame anymore,
stop using it here too. Use funcspdelta, which tells us the exact
difference between the FP and SP. If it's zero, LR has not been
saved yet, so the one saved for sigpanic should be recorded.

This fixes TestBreakpoint on both ppc64 and ppc64le.
I don't really understand how it ever worked there.

Change-Id: I2d2c580d5c0252cc8471e828980aeedcab76858d
Reviewed-on: https://go-review.googlesource.com/6430
Reviewed-by: Minux Ma <minux@golang.org>
2015-03-02 05:32:05 +00:00
David du Colombier
5c2233f261 runtime: don't use /dev/random on Plan 9
Plan 9 provides a /dev/random device to return a
stream of random numbers. However, the method used
to generate random numbers on Plan 9 is slow and
reading from /dev/random may block.

We don't want our Go programs to be significantly
slowed down just to slightly improve the distribution
of hash values.

So, we do the same thing as NaCl and rely exclusively
on extendRandom to generate pseudo-random numbers.

Fixes #10028.

Change-Id: I7e11a9b109c22f23608eb09c406b7c3dba31f26a
Reviewed-on: https://go-review.googlesource.com/6386
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-03-01 18:33:56 +00:00
Jan Kratochvil
cb37cfa01c runtime: TestGdbPython 'print mapvar' should not need unwinding
issue #10017: TestGdbPython 'print mapvar' is reported to fail on ppc64.
issue #10002: TestGdbPython 'print mapvar' is reported to fail on arm hardfloat.

The testcase now uses plain line number in main.  Unwinding issues are
unrelated to the GDB map prettyprinter feature.

Remove arch-specific t.Skip()s from those two issues.

Fixes #10017
Fixes #10002

Change-Id: I9d50ffe2f3eb7bf65dd17c8c76a2677571de68ba
Reviewed-on: https://go-review.googlesource.com/6267
Reviewed-by: Minux Ma <minux@golang.org>
2015-03-01 10:08:49 +00:00
Russ Cox
dca5f2e9b3 cmd/5l etc: replace C code with Go code
mv cmd/new5l cmd/5l and so on.

Minimal changes to cmd/dist and cmd/go to keep things building.
More can be deleted in followup CLs.

Change-Id: I1449eca7654ce2580d1f413a56dc4a75f3d4618b
Reviewed-on: https://go-review.googlesource.com/6361
Reviewed-by: Rob Pike <r@golang.org>
2015-03-01 00:40:11 +00:00
Dmitry Vyukov
894024f478 runtime: fix traceback from goexit1
We used to not call traceback from goexit1.
But now tracer does it and crashes on amd64p32:

runtime: unexpected return pc for runtime.getg called from 0x108a4240
goroutine 18 [runnable, locked to thread]:
runtime.traceGoEnd()
    src/runtime/trace.go:758 fp=0x10818fe0 sp=0x10818fdc
runtime.goexit1()
    src/runtime/proc1.go:1540 +0x20 fp=0x10818fe8 sp=0x10818fe0
runtime.getg(0x0)
    src/runtime/asm_386.s:2414 fp=0x10818fec sp=0x10818fe8
created by runtime/pprof_test.TestTraceStress
    src/runtime/pprof/trace_test.go:123 +0x500

Return PC from goexit1 points right after goexit (+0x6).
It happens to work most of the time somehow.

This change fixes traceback from goexit1 by adding an additional NOP to goexit.

Fixes #9931

Change-Id: Ied25240a181b0a2d7bc98127b3ed9068e9a1a13e
Reviewed-on: https://go-review.googlesource.com/5460
Reviewed-by: Russ Cox <rsc@golang.org>
2015-02-28 23:19:57 +00:00
David Crawshaw
2dbee8919c runtime/cgo: no-op getwd call as test breakpoint
This is to be used by an lldb script inside go_darwin_arm_exec to pause
the execution of tests on iOS so the working directory can be adjusted
into something resembling a GOROOT.

Change-Id: I69ea2d4d871800ae56634b23ffa48583559ddbc6
Reviewed-on: https://go-review.googlesource.com/6363
Reviewed-by: Minux Ma <minux@golang.org>
2015-02-28 22:44:10 +00:00
David Crawshaw
90dbd428e5 runtime/pprof: skip tests that fork on darwin/arm
Change-Id: I9b08b74214e5a41a7e98866a993b038030a4c073
Reviewed-on: https://go-review.googlesource.com/6251
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
2015-02-27 19:55:54 +00:00
Austin Clements
da4874cba4 runtime: trivial clean ups to greyobject
Previously, the typeDead check in greyobject was under a separate
!useCheckmark conditional.  Put it with the rest of the !useCheckmark
code.  Also move a comment about atomic update of the marked bit to
where we actually do that update now.

Change-Id: Ief5f16401a25739ad57d959607b8d81ffe0bc211
Reviewed-on: https://go-review.googlesource.com/6271
Reviewed-by: Rick Hudson <rlh@golang.org>
2015-02-27 19:39:57 +00:00
David Crawshaw
95bf77bc68 runtime: skip tests that need fork on darwin/arm
Change-Id: I1bb0b8b11e8c7686b85657050fd7cf926afe4d29
Reviewed-on: https://go-review.googlesource.com/6200
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
2015-02-27 01:22:55 +00:00
David du Colombier
fb75f856df runtime: fix memory allocator on Plan 9
Previously, the memory allocator on Plan 9 did
not free memory properly. It was only able to
free the last allocated block.

This change implements a variant of the
Kernighan & Ritchie memory allocator with
coalescing and splitting.

The most notable differences are:

- no header is prefixing the allocated blocks, since
  the size is always specified when calling sysFree,
- the free list is nil-terminated instead of circular.

Fixes #9736.
Fixes #9803.
Fixes #9952.

Change-Id: I00d533714e4144a0012f69820d31cbb0253031a3
Reviewed-on: https://go-review.googlesource.com/5524
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
2015-02-26 21:47:16 +00:00
Dave Cheney
3a3c9d6d66 runtime/debug: fix nacl build
Disable the test properly on nacl systems, tested on nacl/amd64p32.

Change-Id: Iffe210be4f9c426bfc47f2dd3a8f0c6b5a398cc3
Reviewed-on: https://go-review.googlesource.com/6093
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-02-26 21:14:03 +00:00
Dave Cheney
f9cc72ccfe runtime: disable scavenger on 64k page size kernels
Update #9993

If the physical page size of the machine is larger than the logical
heap size, for example 8k logical, 64k physical, then madvise(2) will
round up the requested amount to a 64k boundary and may discard pages
close to the page being madvised.

This patch disables the scavenger in these situations, which at the moment
is only ppc64 and ppc64le systems. NaCl also uses a 64k page size, but
it's not clear if it is affected by this problem.

Change-Id: Ib897f8d3df5bd915ddc0b510f2fd90a30ef329ca
Reviewed-on: https://go-review.googlesource.com/6091
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
2015-02-26 20:11:17 +00:00
Russ Cox
a5eda13d20 runtime: disable TestGdbPython on ppc64
(issue #10017)

Change-Id: Ia1267dfdb4474247926a998e32d9c6520015757d
Reviewed-on: https://go-review.googlesource.com/6130
Reviewed-by: Minux Ma <minux@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
2015-02-26 19:43:40 +00:00
David Crawshaw
1e0e2ffb8d runtime: skip test on darwin/arm
Needs the Go tool, which we do not have on iOS. (No Fork.)

Change-Id: Iedf69f5ca81d66515647746546c9b304c8ec10c4
Reviewed-on: https://go-review.googlesource.com/6102
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
2015-02-26 15:31:49 +00:00
Dmitry Vyukov
f47e581e02 runtime: do not do futile netpolls
There is no sense in trying to netpoll while there is
already a thread blocked in netpoll. And in most cases
there must be a thread blocked in netpoll, because
the first otherwise idle thread does blocking netpoll.

On some program I see that netpoll called from findrunnable
consumes 3% of time.

Change-Id: I0af1a73d637bffd9770ea50cb9278839716e8816
Reviewed-on: https://go-review.googlesource.com/4553
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Dmitry Vyukov <dvyukov@google.com>
2015-02-26 11:03:07 +00:00
Matthew Dempsky
3c8a89daf3 runtime: simplify CPU profiling code
This makes Go's CPU profiling code somewhat more idiomatic; e.g.,
using := instead of forward declaring variables, using "int" for
element counts instead of "uintptr", and slices instead of C-style
pointer+length.  This makes the code easier to read and eliminates a
lot of type conversion clutter.

Additionally, in sigprof we can collect just maxCPUProfStack stack
frames, as cpuprof won't use more than that anyway.

Change-Id: I0235b5ae552191bcbb453b14add6d8c01381bd06
Reviewed-on: https://go-review.googlesource.com/6072
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
2015-02-26 08:59:24 +00:00
Josh Bleecher Snyder
1d4bfb3ebb cmd/gc: don't call memequal twice in generated type.eq routines
The first call is pointless. It appears to simply be a mistake.

benchmark                  old ns/op     new ns/op     delta
BenchmarkComplexAlgMap     90.7          76.1          -16.10%

Change-Id: Id0194c9f09cea8b68f17b2ac751a8e3240e47f19
Reviewed-on: https://go-review.googlesource.com/5284
Reviewed-by: Keith Randall <khr@golang.org>
2015-02-26 00:34:29 +00:00
David Crawshaw
7e93610b07 runtime/cgo: fix darwin/arm build
Macro definition ordering.

Change-Id: I0def4702d19a21a68ffa52ea5b7c22578830c578
Reviewed-on: https://go-review.googlesource.com/6030
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
2015-02-25 22:34:26 +00:00
David Crawshaw
b54d313205 runtime/cgo: set the initial working directory
Gives tests a way to find the bundle that contains their testdata, and
is generally useful for finding resources.

Change-Id: Idfa03e8543af927c17bc8ec8aadc5014ec82df28
Reviewed-on: https://go-review.googlesource.com/6000
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
2015-02-25 22:22:02 +00:00
Dave Cheney
c1216c3a33 runtime: skip failing gdb test on linux/arm
Updates #10002

The gdb test added in 1c82e236f5 is failing on most arm systems.

Temporarily disable this test so that we can return to a working arm build.

Change-Id: Iff96ea8d5a99e1ceacf4979e864ff196e5503535
Reviewed-on: https://go-review.googlesource.com/5902
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-02-25 22:13:02 +00:00
Keith Randall
35a59f5c99 runtime: fix build, divide by constant 0 is a compile-time error
Change-Id: Iee319c9f5375c172fb599da77234c10ccb0fd314
Reviewed-on: https://go-review.googlesource.com/6020
Reviewed-by: Keith Randall <khr@golang.org>
2015-02-25 21:39:54 +00:00
Keith Randall
7e1b61c718 runtime: mark pages we return to kernel as NOHUGEPAGE
We return memory to the kernel with madvise(..., DONTNEED).
Also mark returned memory with NOHUGEPAGE to keep the kernel from
merging this memory into a huge page, effectively reallocating it.

Only known to be a problem on linux/{386,amd64,amd64p32} at the moment.
It may come up on other os/arch combinations in the future.

Fixes #8832

Change-Id: Ifffc6627a0296926e3f189a8a9b6e4bdb54c79eb
Reviewed-on: https://go-review.googlesource.com/5660
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
2015-02-25 21:16:18 +00:00
Keith Randall
6d1ebeb527 runtime: handle holes in the heap
We need to distinguish pointers to free spans, which indicate bugs in
our pointer analysis, from pointers to never-in-the-heap spans, which
can legitimately arise from sysAlloc/mmap/etc.  This normally isn't a
problem because the heap is contiguous, but in some situations (32
bit, particularly) the heap must grow around an already allocated
region.

The bad pointer test is disabled so this fix doesn't actually do
anything, but it removes one barrier from reenabling it.

Fixes #9872.

Change-Id: I0a92db4d43b642c58d2b40af69c906a8d9777f88
Reviewed-on: https://go-review.googlesource.com/5780
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
2015-02-25 21:07:10 +00:00
David Crawshaw
85d09574fd runtime: fallback to 128M address space on 32bit
Available darwin/arm devices sporadically have trouble mapping 256M.

I would really appreciate it if anyone could check my working on
this, and make sure sure there aren't obviously bad consequences I
haven't considered.

Change-Id: Id1a8edae104d974fcf5f9333274f958625467f79
Reviewed-on: https://go-review.googlesource.com/5752
Reviewed-by: Keith Randall <khr@golang.org>
2015-02-25 20:02:13 +00:00
Austin Clements
07b73ce146 runtime: simplify gcResetGState
Since allglock is held in this function, there's no point to
tip-toeing around allgs.  Just use a for-range loop.

Change-Id: I1ee61c7e8cac8b8ebc8107c0c22f739db5db9840
Reviewed-on: https://go-review.googlesource.com/5882
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2015-02-25 15:48:57 +00:00
Austin Clements
b3d791c7bb runtime: consolidate gcworkdone/gcscanvalid clearing loops
Previously, we had three loops in the garbage collector that all
cleared the per-G GC flags.  Consolidate these into one function.
This one function is designed to work in a concurrent setting.  As a
result, it's slightly more expensive than the loops it replaces during
STW phases, but these happen at most twice per GC.

Change-Id: Id1ec0074fd58865eb0112b8a0547b267802d0df1
Reviewed-on: https://go-review.googlesource.com/5881
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2015-02-25 15:46:41 +00:00
Austin Clements
37b8597178 runtime: remove unnecessary gcworkdone resetting loop
The loop in gcMark is redundant with the gcworkdone resetting
performed by markroot, which called a few lines later in gcMark.

Change-Id: Ie0a826a614ecfa79e6e6b866e8d1de40ba515856
Reviewed-on: https://go-review.googlesource.com/5880
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2015-02-25 15:46:21 +00:00
Matthew Dempsky
7abdc90fe3 runtime: remove gogetcallerpc and gogetcallersp functions
Package runtime's Go code was converted to directly call getcallerpc
and getcallersp in https://golang.org/cl/138740043, but the assembly
implementations were not removed.

Change-Id: Ib2eaee674d594cbbe799925aae648af782a01c83
Reviewed-on: https://go-review.googlesource.com/5901
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
2015-02-25 09:34:58 +00:00
Matthew Dempsky
2fdb728d01 runtime: simplify NetBSD semaphores
NetBSD's semaphore implementation is derived from OpenBSD's, but has
subsequently diverged due to cleanups that were only applied to the
latter (https://golang.org/cl/137960043, https://golang.org/cl/5563).
This CL applies analogous cleanups for NetBSD.

Notably, we can also remove the scary NetBSD deadlock warning.
NetBSD's manual pages document that lwp_unpark on a not-yet-parked LWP
will cause that LWP's next lwp_park system call to return immediately,
so there's no race hazard.

Change-Id: Ib06844c420d2496ac289748eba13eb4700bbbbb2
Reviewed-on: https://go-review.googlesource.com/5564
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Joel Sing <jsing@google.com>
2015-02-25 03:02:28 +00:00
Jan Kratochvil
1c82e236f5 gdb: fix map prettyprinter
(gdb) p x
Python Exception <class 'gdb.error'> There is no member named b.:
$2 = map[string]string
->
(gdb) p x
$1 = map[string]string = {["shane"] = "hansen"}

Change-Id: I874d02a029f2ac9afc5ab666afb65760ec2c3177
Reviewed-on: https://go-review.googlesource.com/5522
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-02-25 02:36:41 +00:00
Matthew Dempsky
9f926e81c2 runtime: simplify OpenBSD semaphores
OpenBSD's thrsleep system call includes an "abort" parameter, which
specifies a memory address to be tested after being registered on the
sleep channel (i.e., capable of being woken up by thrwakeup).  By
passing a pointer to waitsemacount for this parameter, we avoid race
conditions without needing a lock.  Instead we just need to use
atomicload, cas, and xadd to mutate the semaphore count.

Change-Id: If9f2ab7cfd682da217f9912783cadea7e72283a8
Reviewed-on: https://go-review.googlesource.com/5563
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Joel Sing <jsing@google.com>
2015-02-25 02:30:11 +00:00
Rick Hudson
e31e35a0de runtime: reset gcscanvalid and gcworkdone when GODEBUG=gctrace=2
When GODEBUG=gctrace=2 two gcs are preformed. During the first gc
the stack scan sets the g's gcscanvalid and gcworkdone flags to true
indicating that the stacks have to be scanned and do not need to
be rescanned. These need to be reset to false for the second GC so the
stacks are rescanned, otherwise if the only pointer to an object is
on the stack it will not be discovered and the object will be freed.
Typically this will include the object that was just allocated in
the mallocgc call that initiated the GC.

Change-Id: Ic25163f4689905fd810c90abfca777324005c02f
Reviewed-on: https://go-review.googlesource.com/5861
Reviewed-by: Russ Cox <rsc@golang.org>
2015-02-25 00:14:42 +00:00
Dmitry Vyukov
edcad8639a sync: add active spinning to Mutex
Currently sync.Mutex is fully cooperative. That is, once contention is discovered,
the goroutine calls into scheduler. This is suboptimal as the resource can become
free soon after (especially if critical sections are short). Server software
usually runs at ~~50% CPU utilization, that is, switching to other goroutines
is not necessary profitable.

This change adds limited active spinning to sync.Mutex if:
1. running on a multicore machine and
2. GOMAXPROCS>1 and
3. there is at least one other running P and
4. local runq is empty.
As opposed to runtime mutex we don't do passive spinning,
because there can be work on global runq on on other Ps.

benchmark                   old ns/op     new ns/op     delta
BenchmarkMutexNoSpin        1271          1272          +0.08%
BenchmarkMutexNoSpin-2      702           683           -2.71%
BenchmarkMutexNoSpin-4      377           372           -1.33%
BenchmarkMutexNoSpin-8      197           190           -3.55%
BenchmarkMutexNoSpin-16     131           122           -6.87%
BenchmarkMutexNoSpin-32     170           164           -3.53%
BenchmarkMutexSpin          4724          4728          +0.08%
BenchmarkMutexSpin-2        2501          2491          -0.40%
BenchmarkMutexSpin-4        1330          1325          -0.38%
BenchmarkMutexSpin-8        684           684           +0.00%
BenchmarkMutexSpin-16       414           372           -10.14%
BenchmarkMutexSpin-32       559           469           -16.10%

BenchmarkMutex                 19.1          19.1          +0.00%
BenchmarkMutex-2               81.6          54.3          -33.46%
BenchmarkMutex-4               143           100           -30.07%
BenchmarkMutex-8               154           156           +1.30%
BenchmarkMutex-16              140           159           +13.57%
BenchmarkMutex-32              141           163           +15.60%
BenchmarkMutexSlack            33.3          31.2          -6.31%
BenchmarkMutexSlack-2          122           97.7          -19.92%
BenchmarkMutexSlack-4          168           158           -5.95%
BenchmarkMutexSlack-8          152           158           +3.95%
BenchmarkMutexSlack-16         140           159           +13.57%
BenchmarkMutexSlack-32         146           162           +10.96%
BenchmarkMutexWork             154           154           +0.00%
BenchmarkMutexWork-2           89.2          89.9          +0.78%
BenchmarkMutexWork-4           139           86.1          -38.06%
BenchmarkMutexWork-8           177           162           -8.47%
BenchmarkMutexWork-16          170           173           +1.76%
BenchmarkMutexWork-32          176           176           +0.00%
BenchmarkMutexWorkSlack        160           160           +0.00%
BenchmarkMutexWorkSlack-2      103           99.1          -3.79%
BenchmarkMutexWorkSlack-4      155           148           -4.52%
BenchmarkMutexWorkSlack-8      176           170           -3.41%
BenchmarkMutexWorkSlack-16     170           173           +1.76%
BenchmarkMutexWorkSlack-32     175           176           +0.57%

"No work" benchmarks are not very interesting (BenchmarkMutex and
BenchmarkMutexSlack), as they are absolutely not realistic.

Fixes #8889

Change-Id: I6f14f42af1fa48f73a776fdd11f0af6dd2bb428b
Reviewed-on: https://go-review.googlesource.com/5430
Reviewed-by: Rick Hudson <rlh@golang.org>
Run-TryBot: Dmitry Vyukov <dvyukov@google.com>
2015-02-24 10:53:48 +00:00
Russ Cox
b986f3e3b5 all: merge dev.cc (a91c2e0) into master
This change deletes the C implementations of
the Go compiler and assembler from the master branch.

The Go implementations are a bit slower right now,
due mainly to garbage generated by taking addresses
of stack variables all over the place (it was C code,
after all). That will be cleaned up (mechanically) over the
next week or so, and things will get faster.

Change-Id: I66b2b3477aec8835f9960d0798f5752dcd98d08f
2015-02-23 16:52:29 -05:00
Austin Clements
bceb18e498 runtime: eliminate unnecessary assumption in heapBitsForObject
The slow path of heapBitsForObjects somewhat subtly assumes that the
pointer will not point to the first word of the object and will round
the pointer wrong if this assumption is violated.  This assumption is
safe because the fast path should always take care of this case, but
there's no benefit to making this assumption, it makes the code more
difficult to experiment with than necessary, and it's trivial to
eliminate.

Change-Id: Iedd336f7d529a27d3abeb83e77dfb32a285ea73a
Reviewed-on: https://go-review.googlesource.com/5636
Reviewed-by: Russ Cox <rsc@golang.org>
2015-02-23 21:49:27 +00:00
Shenghou Ma
f0bbb5c450 runtime/pprof: make TestBlockProfile more robust
It's using debug mode of pprof.writeBlock, so the output actually goes
through text/tabwriter. It is possible that tabwriter expands each tab
into multiple tabs in certain cases.

For example, this output has been observed on the new arm64 port:
10073805 1 @ 0x1088ec 0xd1b8c 0xd0628 0xb68c0 0x867f4
#	0x1088ec	sync.(*Cond).Wait+0xfc				/home/minux/go.git/src/sync/cond.go:63
#	0xd1b8c		runtime/pprof_test.blockCond+0x22c		/home/minux/go.git/src/runtime/pprof/pprof_test.go:454
#	0xd0628		runtime/pprof_test.TestBlockProfile+0x1b8	/home/minux/go.git/src/runtime/pprof/pprof_test.go:359
#	0xb68c0		testing.tRunner+0x140				/home/minux/go.git/src/testing/testing.go:447

10069965 1 @ 0x14008 0xd1390 0xd0628 0xb68c0 0x867f4
#	0x14008	runtime.chansend1+0x48				/home/minux/go.git/src/runtime/chan.go:76
#	0xd1390	runtime/pprof_test.blockChanSend+0x100		/home/minux/go.git/src/runtime/pprof/pprof_test.go:396
#	0xd0628	runtime/pprof_test.TestBlockProfile+0x1b8	/home/minux/go.git/src/runtime/pprof/pprof_test.go:359
#	0xb68c0	testing.tRunner+0x140				/home/minux/go.git/src/testing/testing.go:447

10069706 1 @ 0x108e0c 0xd193c 0xd0628 0xb68c0 0x867f4
#	0x108e0c	sync.(*Mutex).Lock+0x19c			/home/minux/go.git/src/sync/mutex.go:67
#	0xd193c		runtime/pprof_test.blockMutex+0xbc		/home/minux/go.git/src/runtime/pprof/pprof_test.go:441
#	0xd0628		runtime/pprof_test.TestBlockProfile+0x1b8	/home/minux/go.git/src/runtime/pprof/pprof_test.go:359
#	0xb68c0		testing.tRunner+0x140				/home/minux/go.git/src/testing/testing.go:447

Change-Id: I3bef778c5fe01a894cfdc526fdc5fecb873b8ade
Signed-off-by: Shenghou Ma <minux@golang.org>
Reviewed-on: https://go-review.googlesource.com/5554
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
2015-02-23 21:05:55 +00:00
Russ Cox
e8d9c8d163 [dev.cc] all: merge master (6a10f72) into dev.cc
To pick up darwin/arm fix and hopefully fix build.

Change-Id: I06996d0b13b777e476f65405aee031482fc76439
2015-02-23 14:28:54 -05:00
Rick Hudson
99482f2f9e runtime: Add prefetch to allocation code
The routine mallocgc retrieves objects from freelists. Prefetch
the object that will be returned in the next call to mallocgc.
Experiments indicate that this produces a 1% improvement when using
prefetchnta and less when using prefetcht0, prefetcht1, or prefetcht2.

Benchmark numbers indicate a 1% improvement over no
prefetch, much less over prefetcht0, prefetcht1, and prefetcht2.
These numbers were for the garbage benchmark with MAXPROCS=4
no prefetch                          >> 5.96 / 5.77 / 5.89
prefetcht0(uintptr(v.ptr().next))    >> 5.88 / 6.17 / 5.84
prefetcht1(uintptr(v.ptr().next))    >> 5.88 / 5.89 / 5.91
prefetcht2(uintptr(v.ptr().next))    >> 5.87 / 6.47 / 5.92
prefetchnta(uintptr(v.ptr().next))   >> 5.72 / 5.84 / 5.85

Change-Id: I54e07172081cccb097d5b5ce8789d74daa055ed9
Reviewed-on: https://go-review.googlesource.com/5350
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Austin Clements <austin@google.com>
2015-02-23 18:52:43 +00:00
Russ Cox
c72a21189b [dev.cc] runtime, syscall: add names to FP offsets in freebsd, netbsd arm assembly
Makes them compatible with the new asm.
Applied mechanically from vet diagnostics.

Manual edits: the names for arguments in time·now(SB) in runtime/sys_*_arm.s.

Change-Id: Ib295390d9509d306afc67714e3f50dc832256625
Reviewed-on: https://go-review.googlesource.com/5576
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
2015-02-23 16:52:33 +00:00