- Some sequencing issues with stopping the first gc_m round
at the right place to set up correctly for the second round.
- atomicxor8 is not idempotent; avoid xor.
- Maintain BitsDead type bits correctly; see long comment added.
- Enable checkmark phase by default for now.
LGTM=rlh
R=rlh
CC=golang-codereviews
https://golang.org/cl/171090043
This adds an independent mark phase to the GC that can be used to
verify the the default concurrent mark phase has found all reachable
objects. It uses the upper 2 bits of the boundary nibble to encode
the mark leaving the lower bits to encode the boundary and the
normal mark bit.
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/167130043
Previously, the flags argument to mallocgc was an int in Go,
but a uint32 in C. Change the Go type to use uint32 so these
agree. The largest flag value is 2 (and of course no flag
values are negative), so this won't change anything on little
endian architectures, but it matters on big endian.
LGTM=rsc
R=khr, rsc
CC=golang-codereviews
https://golang.org/cl/169920043
The GC info masks for slices and strings were changed in
commit caab29a25f68, but the reference masks used by
gcinfo_test for power64x hadn't caught up. Now they're
identical to amd64, so this CL fixes this test by combining
the reference masks for these platforms.
LGTM=rsc
R=rsc, dave
CC=golang-codereviews
https://golang.org/cl/162620044
fastrand1 depends on testing the high bit of its uint32 state.
For efficiency, all of the architectures implement this as a
sign bit test. However, on power64, fastrand1 was using a
64-bit sign test on the zero-extended 32-bit state. This
always failed, causing fastrand1 to have very short periods
and often decay to 0 and get stuck.
Fix this by using a 32-bit signed compare instead of a 64-bit
compare. This fixes various tests for the randomization of
select of map iteration.
LGTM=rsc
R=rsc, dave
CC=golang-codereviews
https://golang.org/cl/166990043
All three cases of clearfat were wrong on power64x.
The cases that handle 1032 bytes and up and 32 bytes and up
both use MOVDU (one directly generated in a loop and the other
via duffzero), which leaves the pointer register pointing at
the *last written* address. The generated code was not
accounting for this, so the byte fill loop was re-zeroing the
last zeroed dword, rather than the bytes following the last
zeroed dword. Fix this by simply adding an additional 8 byte
offset to the byte zeroing loop.
The case that handled under 32 bytes was also wrong. It
didn't update the pointer register at all, so the byte zeroing
loop was simply re-zeroing the beginning of region. Again,
the fix is to add an offset to the byte zeroing loop to
account for this.
LGTM=dave, bradfitz
R=rsc, dave, bradfitz
CC=golang-codereviews
https://golang.org/cl/168870043
Apparently I had already moved on to fixing another problem
when I submitted CL 169790043.
LGTM=dave
R=rsc, dave
CC=golang-codereviews
https://golang.org/cl/165210043
No real problems found. Just lots of argument names that
didn't quite match up.
LGTM=rsc
R=rsc, dave
CC=golang-codereviews
https://golang.org/cl/169790043
This adds a test to runtime·check to ensure CAS of large
unsigned 32-bit numbers does not accidentally sign-extend its
arguments.
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/162490044
Previously, the power64x runtime assembly was sloppy about
using sign-extending versus zero-extending moves of arguments
and return values. I think all of the cases that actually
mattered have been fixed in recent CLs; this CL fixes up the
few remaining mismatches.
LGTM=rsc
R=rsc, dave
CC=golang-codereviews
https://golang.org/cl/162480043
This CL implements the many multiword write barriers by calling
writebarrierptr, so that only writebarrierptr needs the actual barrier.
In lieu of an actual barrier, writebarrierptr checks that the value
being copied is not a small non-zero integer. This is enough to
shake out bugs where the barrier is being called when it should not
(for non-pointer values). It also found a few tests in sync/atomic
that were being too clever.
This CL adds a write barrier for the memory moved during the
builtin copy function, which I forgot when inserting barriers for Go 1.4.
This CL re-enables some write barriers that were disabled for Go 1.4.
Those were disabled because it is possible to change the generated
code so that they are unnecessary most of the time, but we have not
changed the generated code yet. For safety they must be enabled.
None of this is terribly efficient. We are aiming for correct first.
LGTM=rlh
R=rlh
CC=golang-codereviews
https://golang.org/cl/168770043
If you get a stack of PCs from Callers, it would be expected
that every PC is immediately after a call instruction, so to find
the line of the call, you look up the line for PC-1.
CL 163550043 now explicitly documents that.
The most common exception to this is the top-most return PC
on the stack, which is the entry address of the runtime.goexit
function. Subtracting 1 from that PC will end up in a different
function entirely.
To remove this special case, make the top-most return PC
goexit+PCQuantum and then implement goexit in assembly
so that the first instruction can be skipped.
Fixes#7690.
LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/170720043
Originally traceback was only used for printing the stack
when an unexpected signal came in. In that case, the
initial PC is taken from the signal and should be used
unaltered. For the callers, the PC is the return address,
which might be on the line after the call; we subtract 1
to get to the CALL instruction.
Traceback is now used for a variety of things, and for
almost all of those the initial PC is a return address,
whether from getcallerpc, or gp->sched.pc, or gp->syscallpc.
In those cases, we need to subtract 1 from this initial PC,
but the traceback code had a hard rule "never subtract 1
from the initial PC", left over from the signal handling days.
Change gentraceback to take a flag that specifies whether
we are tracing a trap.
Change traceback to default to "starting with a return PC",
which is the overwhelmingly common case.
Add tracebacktrap, like traceback but starting with a trap PC.
Use tracebacktrap in signal handlers.
Fixes#7690.
LGTM=iant, r
R=r, iant
CC=golang-codereviews
https://golang.org/cl/167810044
Attempt to clear up confusion about how to turn
the PCs reported by Callers into the file and line
number people actually want.
Fixes#7690.
LGTM=r, chris.cs.guy
R=r, chris.cs.guy
CC=golang-codereviews
https://golang.org/cl/163550043
The goal here is to get the big-endian fixes so that
in some upcoming code movement for write barriers
I don't make them unmergeable.
LGTM=rlh
R=rlh
CC=golang-codereviews
https://golang.org/cl/166890043
goprintf is a printf-like print for Go.
It is used in the code generated by 'defer print(...)' and 'go print(...)'.
Normally print(1, 2, 3) turns into
printint(1)
printint(2)
printint(3)
but defer and go need a single function call to give the runtime;
they give the runtime something like goprintf("%d%d%d", 1, 2, 3).
Variadic functions like goprintf cannot be described in the new
type information world, so we have to replace it.
Replace with a custom function, so that defer print(1, 2, 3) turns
into
defer func(a1, a2, a3 int) {
print(a1, a2, a3)
}(1, 2, 3)
(and then the print becomes three different printints as usual).
Fixes#8614.
LGTM=austin
R=austin
CC=golang-codereviews, r
https://golang.org/cl/159700043
I removed support for jumping between functions years ago,
as part of doing the instruction layout for each function separately.
Given that, it makes sense to treat labels as function-scoped.
This lets each function have its own 'loop' label, for example.
Makes the assembly much cleaner and removes the last
reason anyone would reach for the 123(PC) form instead.
Note that this is on the dev.power64 branch, but it changes all
the assemblers. The change will ship in Go 1.5 (perhaps after
being ported into the new assembler).
Came up as part of CL 167730043.
LGTM=r
R=r
CC=austin, dave, golang-codereviews, minux
https://golang.org/cl/159670043
Power64 servers do not currently support sub-word size atomic
memory access, so atomicor8 uses word size atomic access.
However, previously atomicor8 made no attempt to align this
access, resulting in errors. Fix this by aligning the pointer
to a word boundary and shifting the value appropriately.
Since atomicor8 is used in GC, add a test to runtime·check to
make sure this doesn't break in the future.
This also fixes an incorrect branch label, an incorrectly
sized argument move, and adds argument names to help go vet.
LGTM=rsc
R=rsc, dave
CC=golang-codereviews
https://golang.org/cl/165820043
Fix include paths that got moved in the great pkg/ rename. Add
missing runtime/arch_* files for power64. Port changes that
happened on default since branching to
runtime/{asm,atomic,sys_linux}_power64x.s (precise stacks,
calling convention change, various new and deleted functions.
Port struct renaming and fix some bugs in
runtime/defs_linux_power64.h.
LGTM=rsc
R=rsc, dave
CC=golang-codereviews
https://golang.org/cl/161450043
The ftab ends with a half functab record consisting only of
the 'entry' field followed by a uint32 giving the offset of
the next table. Previously, symtabinit assumed it could read
this uint32 as a uintptr. Since this is unsafe on big endian,
explicitly read the offset as a uint32.
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/157660043
Routines and logic to preform a concurrent stack scan of go-routines.
This CL excersizes most of the functionality needed. The
major exception being that it does not scan running goroutines.
After doing the scans it relies on a STW to finish the GC, including
rescanning the stacks. It is intended to achieve correctness,
performance will follow.
LGTM=rsc
R=golang-codereviews, rsc
CC=dvyukov, golang-codereviews
https://golang.org/cl/156580043
The changes got rid of the problems we were seeing.
We suspect the pushcnt field has a race.
LGTM=rsc
R=dvyukov, rsc
CC=golang-codereviews
https://golang.org/cl/159330043
Also updated defs3_linux.go but had to manually edit defs_linux_power64le.h. Will regenerate the file when cgo is working natively on ppc64.
LGTM=austin
R=rsc, austin
CC=golang-codereviews
https://golang.org/cl/158360043
go_bootstrap was panicking during runtime initialization
(under runtime.main) because Defer objects were being
prematurely GC'd. This happened because of an incorrect
change to runtime·unrollgcprog_m to make it endian-agnostic
during the conversion of runtime bitmaps to byte arrays.
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/161960044
This brings dev.power64 up-to-date with the current tip of
default. go_bootstrap is still panicking with a bad defer
when initializing the runtime (even on amd64).
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/152570049
The earlier dev.power64 merge missed the port of
runtime/noasm.goc to runtime/noasm_arm.go. This CL fixes this
by moving noasm_arm.go to noasm.go and adding a +build to
share the file between arm and power64.
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/158350043
This also removes pkg/runtime/traceback_lr.c, which was ported
to Go in an earlier commit and then moved to
runtime/traceback.go.
Reviewer: rsc@golang.org
rsc: LGTM
Fixes#8348.
Trying to work around clang's dodgy support for .arch by reverting to the external assembler didn't work out so well. Minux had a much better solution to encode the instructions we need as .word directives which avoids .arch altogether.
I've confirmed with gdb that this form produces the expected machine code
Dump of assembler code for function crosscall_arm1:
0x00000000 <+0>: push {r4, r5, r6, r7, r8, r9, r10, r11, r12, lr}
0x00000004 <+4>: mov r4, r0
0x00000008 <+8>: mov r5, r1
0x0000000c <+12>: mov r0, r2
0x00000010 <+16>: blx r5
0x00000014 <+20>: blx r4
0x00000018 <+24>: pop {r4, r5, r6, r7, r8, r9, r10, r11, r12, pc}
There is another compilation failure that blocks building Go with clang on arm
# ../misc/cgo/test
# _/home/dfc/go/misc/cgo/test
/tmp/--407b12.s: Assembler messages:
/tmp/--407b12.s:59: Error: selected processor does not support ARM mode `blx r0'
clang: error: assembler command failed with exit code 1 (use -v to see invocation)
FAIL _/home/dfc/go/misc/cgo/test [build failed]
I'll open a new issue for that
LGTM=iant
R=iant, minux
CC=golang-codereviews
https://golang.org/cl/158180047
Get rid of gocputicks(), it is no longer used.
LGTM=bradfitz, dave
R=golang-codereviews, bradfitz, dave, minux
CC=golang-codereviews
https://golang.org/cl/161110044
It has been failing periodically on Solaris/x64.
Change blockevent so it always records an event if we called
SetBlockProfileRate(1), even if the time delta is negative or zero.
Hopefully this will fix the test on Solaris.
Caveat: I don't actually know what the Solaris problem is, this
is just an educated guess.
LGTM=dave
R=dvyukov, dave
CC=golang-codereviews
https://golang.org/cl/159150043
Russ Cox pointed out that environment strings are not
required to be nil-terminated on Plan 9.
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/159130044
select {
case <- c:
case <- c:
}
In this case, c.recvq lists two SudoGs which have the same G.
So we can't use the G as the key to dequeue the correct SudoG,
as that key is ambiguous. Dequeueing the wrong SudoG ends up
freeing a SudoG that is still in c.recvq.
The fix is to use the actual SudoG pointer as the key.
LGTM=dvyukov
R=rsc, bradfitz, dvyukov, khr
CC=austin, golang-codereviews
https://golang.org/cl/159040043
Don't use cmd/pprof as it is not necessary installed
and does not work on nacl and plan9.
Instead just look at the raw profile.
LGTM=crawshaw, rsc
R=golang-codereviews, crawshaw, 0intro, rsc
CC=golang-codereviews
https://golang.org/cl/159010043
gogo called from GC is okay
for the same reasons that
gogo called from System or ExternalCode is okay.
All three are fake stack traces.
Fixes#8408.
LGTM=dvyukov, r
R=r, dvyukov
CC=golang-codereviews
https://golang.org/cl/152580043
Dmitriy believes this broke Windows.
It looks like build.golang.org stopped before that,
but it's worth a shot.
««« original CL description
runtime: make pprof a little nicer
Update #8942
This does not fully address issue 8942 but it does make
the profiles much more useful, until that issue can be
fixed completely.
LGTM=dvyukov
R=r, dvyukov
CC=golang-codereviews
https://golang.org/cl/159990043
»»»
TBR=dvyukov
CC=golang-codereviews
https://golang.org/cl/160030043
hg was unable to create a CL on the code review server for this,
so I am submitting the merge by hand.
The only manual edits are in mgc0.c, to reapply the
removal of cached/ncached to the new code.
It cannot run 'go tool pprof'. There is no guarantee that's installed.
It needs to build a temporary pprof binary and run that.
It also needs to skip the test on systems that can't build and
run binaries, namely android and nacl.
See src/cmd/nm/nm_test.go's TestNM for a template.
Update #8867
Status: Accepted
TBR=dvyukov
CC=golang-codereviews
https://golang.org/cl/153710043
Update #8942
This does not fully address issue 8942 but it does make
the profiles much more useful, until that issue can be
fixed completely.
LGTM=dvyukov
R=r, dvyukov
CC=golang-codereviews
https://golang.org/cl/159990043
There are 3 issues:
1. Skip argument of callers is off by 3,
so that all allocations are deep inside of memory profiler.
2. Memory profiling statistics are not updated after runtime.GC.
3. Testing package does not update memory profiling statistics
before capturing the profile.
Also add an end-to-end test.
Fixes#8867.
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/148710043
A Go prototype can be used instead now, and the compiler
will do a better job than we will doing it by hand.
(We got it wrong in amd64p32, causing the current build
breakage.)
The auto-prototype-matching only applies to functions
without an explicit package path, so the TEXT lines for
reflectcall and callXX are s/runtime·/·/.
LGTM=khr
R=khr
CC=golang-codereviews, iant, r
https://golang.org/cl/153600043
The racewalk code was not updated for the new write barriers.
Make it more future-proof.
The new write barrier code assumed that +1 pointer would
be aligned properly for any type that might follow, but that's
not true on 32-bit systems where some types are 64-bit aligned.
The only system like that today is nacl/amd64p32.
Insert a dummy pointer so that the ambiguously typed
value is at +2 pointers, which is always max-aligned.
LGTM=r
R=r
CC=golang-codereviews, iant, khr
https://golang.org/cl/158890046
includes undo of 22318cd31d7d and also:
- always use SetUnhandledExceptionFilter on windows-386;
- crash when receive EXCEPTION_BREAKPOINT in exception handler.
Fixes#8006.
LGTM=rsc
R=golang-codereviews, rsc
CC=golang-codereviews
https://golang.org/cl/155360043
Assignments of 2-, 3-, and 4-word values were handled
by individual MOV instructions (and for scalars still are).
But if there are pointers involved, those assignments now
go through the write barrier routine. Before this CL, they
went to writebarrierfat, which calls memmove.
Memmove is too much overhead for these small
amounts of data.
Instead, call writebarrierfat{2,3,4}, which are specialized
for the specific amount of data being copied.
Today the write barrier does not care which words are
pointers, so size alone is enough to distinguish the cases.
If we keep these distinctions in Go 1.5 we will need to
expand them for all the pointer-vs-scalar possibilities,
so the current 3 functions will become 3+7+15 = 25,
still not a large burden (we deleted more morestack
functions than that when we dropped segmented stacks).
BenchmarkBinaryTree17 3250972583 3123910344 -3.91%
BenchmarkFannkuch11 3067605223 2964737839 -3.35%
BenchmarkFmtFprintfEmpty 101 96.0 -4.95%
BenchmarkFmtFprintfString 267 235 -11.99%
BenchmarkFmtFprintfInt 261 253 -3.07%
BenchmarkFmtFprintfIntInt 444 402 -9.46%
BenchmarkFmtFprintfPrefixedInt 374 346 -7.49%
BenchmarkFmtFprintfFloat 472 449 -4.87%
BenchmarkFmtManyArgs 1537 1476 -3.97%
BenchmarkGobDecode 13986528 12432985 -11.11%
BenchmarkGobEncode 13120323 12537420 -4.44%
BenchmarkGzip 451925758 437500578 -3.19%
BenchmarkGunzip 113267612 110053644 -2.84%
BenchmarkHTTPClientServer 103151 77100 -25.26%
BenchmarkJSONEncode 25002733 23435278 -6.27%
BenchmarkJSONDecode 94213717 82568789 -12.36%
BenchmarkMandelbrot200 4804246 4713070 -1.90%
BenchmarkGoParse 4646114 4379456 -5.74%
BenchmarkRegexpMatchEasy0_32 163 158 -3.07%
BenchmarkRegexpMatchEasy0_1K 433 391 -9.70%
BenchmarkRegexpMatchEasy1_32 154 138 -10.39%
BenchmarkRegexpMatchEasy1_1K 1481 1132 -23.57%
BenchmarkRegexpMatchMedium_32 282 270 -4.26%
BenchmarkRegexpMatchMedium_1K 92421 86149 -6.79%
BenchmarkRegexpMatchHard_32 5209 4718 -9.43%
BenchmarkRegexpMatchHard_1K 158141 147921 -6.46%
BenchmarkRevcomp 699818791 642222464 -8.23%
BenchmarkTemplate 132402383 108269713 -18.23%
BenchmarkTimeParse 509 478 -6.09%
BenchmarkTimeFormat 462 456 -1.30%
LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/156200043
Comments lay out the concurrent GC algorithms.
This CL implements parts of the algorithm.
The acknowledgement code has been removed from this CL
LGTM=rsc, dvyukov
R=dvyukov, rsc
CC=golang-codereviews
https://golang.org/cl/151540043
That was complete failure - builders are broken,
but original cl worked fine on my system.
I will need access to builders
to test this change properly.
««« original CL description
runtime: handle all windows exception
Fixes#8006.
LGTM=rsc
R=golang-codereviews, rsc
CC=golang-codereviews
https://golang.org/cl/145150043
»»»
TBR=rsc
R=golang-codereviews
CC=golang-codereviews
https://golang.org/cl/154180043
In channels, zeroing of gp.waiting is missed on a closed channel panic.
m.morebuf.g is not zeroed.
I don't expect the latter causes any problems, but just in case.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/151610043
This change prevents confusion in the garbage collector.
The collector wants to make sure that every pointer it finds
isn't junk. Its criteria for junk is (among others) points
to a "free" span.
Because the stack shrinker modifies pointers in the heap,
there is a race condition between the GC scanner and the
shrinker. The GC scanner can see old pointers (pointers to
freed stacks). In particular this happens with SudoG.elem
pointers.
Normally this is not a problem, as pointers into stack spans
are ok. But if the freed stack is the last one in its span,
the span is marked as "free" instead of "contains stacks".
This change makes sure that even if the GC scanner sees
an old pointer, the span into which it points is still
marked as "contains stacks", and thus the GC doesn't
complain about it.
This change will make the GC pause a tiny bit slower, as
the stack freeing now happens in serial with the mark pause.
We could delay the freeing until the mutators start back up,
but this is the simplest change for now.
TBR=dvyukov
CC=golang-codereviews
https://golang.org/cl/158750043
The change contains 3 spot optimizations to scan loop:
1. Don't use byte vars, use uintptr's instead.
This seems to alleviate some codegen issue,
and alone accounts to a half of speedup.
2. Remove bitmap cache. Currently we cache only 1 byte,
so caching is not particularly effective anyway.
Removal of the cache simplifies code and positively affects regalloc.
3. Replace BitsMultiword switch with if and
do debug checks only in Debug mode.
I've benchmarked changes separately and ensured that
each of them provides speedup on top of the previous one.
This change as a whole fixes the unintentional regressions
of scan loop that were introduced during development cycle.
Fixes#8625.
Fixes#8565.
On go.benchmarks/garbage benchmark:
GOMAXPROCS=1
time: -3.13%
cputime: -3.22%
gc-pause-one: -15.71%
gc-pause-total: -15.71%
GOMAXPROCS=32
time: -1.96%
cputime: -4.43%
gc-pause-one: -6.22%
gc-pause-total: -6.22%
LGTM=khr, rsc
R=golang-codereviews, khr
CC=golang-codereviews, rlh, rsc
https://golang.org/cl/153990043
Out of stack space due to new 2-word call in freedefer.
Go back to smaller function calls.
TBR=brainman
CC=golang-codereviews
https://golang.org/cl/152340043
It appears to be an opaque bit pattern more than a pointer.
The Go garbage collector has discovered that for m0
it is set to 0x4c.
Should fix Windows build.
TBR=brainman
CC=golang-codereviews
https://golang.org/cl/149640043
Another dangling stack pointer in a cached structure.
Same as SudoG.elem and SudoG.selectdone.
Definitely a fix, and the new test in freedefer makes the
crash reproducible, but probably not a complete fix.
I have seen one dangling pointer in a Defer.panic even
after this fix; I cannot see where it could be coming from.
I think this will fix the solaris build.
I do not think this will fix the occasional failure on the darwin build.
TBR=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/155080043
I have a CL which at every gc looks through data and bss
sections for nonpointer data (according to gc maps) that
looks like a pointer. These are potential missing roots.
The only thing it finds are begnign, storing stack pointers
into m0.scalararg[1] and never cleaning them up. Let's
clean them up now so the test CL passes all.bash cleanly.
The test CL can't be checked in because we might store
pointer-looking things in nonpointer data by accident.
LGTM=iant
R=golang-codereviews, iant, khr
CC=golang-codereviews
https://golang.org/cl/153210043
We no longer have full type information in the heap, so
we can't dump that any more. Instead we dump ptr/noptr
maps so at least we can compute graph connectivity.
In addition, we still dump Iface/Eface types so together
with dwarf type info we might be able to reconstruct
types of most things in the heap.
LGTM=dvyukov
R=golang-codereviews, dvyukov, rsc, khr
CC=golang-codereviews
https://golang.org/cl/155940043
This will help find bugs during the release freeze.
It's not clear it should be kept for the release itself.
That's issue 8861.
The most likely thing that would trigger this is stale
pointers that previously were ignored or caused memory
leaks. These were allowed due to the use of conservative
collection. Now that everything is precise, we should not
see them anymore.
The small number check reinforces what the stack copier
is already doing, catching the storage of integers in pointers.
It caught issue 8864.
The check is disabled if _cgo_allocate is linked into the binary,
which is to say if the binary is using SWIG to allocate untyped
Go memory. In that case, there are invalid pointers and there's
nothing we can do about it.
LGTM=rlh
R=golang-codereviews, dvyukov, rlh
CC=golang-codereviews, iant, khr, r
https://golang.org/cl/148470043
Depending on flags&KindGCProg,
gc[0] and gc[1] are either pointers or inlined bitmap bits.
That's not compatible with a precise garbage collector:
it needs to be always pointers or never pointers.
Change the inlined bitmap case to store a pointer to an
out-of-line bitmap in gc[0]. The out-of-line bitmaps are
dedup'ed, so that for example all pointer types share the
same out-of-line bitmap.
Fixes#8864.
LGTM=r
R=golang-codereviews, dvyukov, r
CC=golang-codereviews, iant, khr, rlh
https://golang.org/cl/155820043
At last minute before 1.3 we relaxed SetFinalizer to avoid
crashes when you pass the result of a global alloc to it.
This avoids the crash but makes SetFinalizer a bit too relaxed.
Document that the finalizer of a global allocation may not run.
Tighten the SetFinalizer check to ignore a global allocation but
not ignore everything else.
Fixes#7656.
LGTM=r, iant
R=golang-codereviews, iant, r
CC=dvyukov, golang-codereviews, khr, rlh
https://golang.org/cl/145930043
Removes another dangling pointer that might
cause a memory leak in 1.4 or crash the GC in 1.5.
LGTM=rlh
R=golang-codereviews
CC=golang-codereviews, iant, khr, r, rlh
https://golang.org/cl/150520043
This change was necessary on the dev.garbage branch
to keep the garbage collector from seeing pointers into
invalid heap areas.
On this default (Go 1.4) branch, the change removes
some possibility for memory leaks.
LGTM=khr
R=golang-codereviews, khr
CC=golang-codereviews, iant, r, rlh
https://golang.org/cl/155760043
Structs without tags have no unique name to use in the
Go definitions generated from the C types.
This caused issue 8812, fixed by CL 149260043.
Avoid future problems by requiring struct tags.
Update runtime as needed.
(There is no other C code in the tree.)
LGTM=bradfitz, iant
R=golang-codereviews, bradfitz, dave, iant
CC=golang-codereviews, khr, r
https://golang.org/cl/150360043
Refactoring of the scan and mark phase so that concurrent GC,
in particular the write barrier, can share a common infrastructure.
Now that the scan and mark phases have been separated
we will be able to scan stacks without blackening any objects.
This in turn will allow us to delay installing expensive write barrier code.
LGTM=rsc
R=rsc, khr, dvyukov
CC=golang-codereviews
https://golang.org/cl/145640044
In old conservative Go, this could cause memory leaks.
A new pickier collector might reasonably crash when it saw one of these.
LGTM=rlh
R=rlh
CC=golang-codereviews
https://golang.org/cl/147480043
Not found because it was not used by name.
Add name in comments for what's left behind.
LGTM=rlh
R=rlh
CC=golang-codereviews
https://golang.org/cl/148430043
GC types were not being generated for the garbage collector
work buffer. The markfor object was being collected as a result.
This broke amd64p32 and maybe plan9 builds. Why it didn't break
every build I'm not sure...
Fixes#8812
LGTM=0intro, rsc
R=golang-codereviews, dave, khr, 0intro, rsc
CC=golang-codereviews
https://golang.org/cl/149260043
Our traceback code needs to know the PC of several special
functions, including goexit, mcall, etc. Make sure that
these PCs are initialized before any traceback occurs.
Fixes#8766
LGTM=rsc
R=golang-codereviews, rsc, khr, bradfitz
CC=golang-codereviews
https://golang.org/cl/145570043
Fixes#8690.
This CL moves the save of LR around BL runtime.read_tls_fallback to liblink as it is not needed when MRC is not replaced.
LGTM=rsc, minux
R=rsc, khr, minux
CC=golang-codereviews
https://golang.org/cl/147310043
We're not comparing with code addresses any more. Instead,
we use nil algorithm functions to mark uncomparable types.
LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/151040044
Need to restore the g register. Somehow this line vaporized from
CL 144130043. Also cgo_topofstack -> _cgo_topofstack, that vaporized also.
TBR=rsc
CC=golang-codereviews
https://golang.org/cl/150940044
During a cgo call, the stack can be copied. This copy invalidates
the pointer that cgo has into the return value area. To fix this
problem, pass the address of the location containing the stack
top value (which is in the G struct). For cgo functions which
return values, read the stktop before and after the cgo call to
compute the adjustment necessary to write the return value.
Fixes#8771
LGTM=iant, rsc
R=iant, rsc, khr
CC=golang-codereviews
https://golang.org/cl/144130043
Fixes linux builds (_vdso); may fix others.
I can at least cross-compile cmd/go for every
implemented system now.
TBR=iant
CC=golang-codereviews
https://golang.org/cl/142630043
Corrections due to new strict type rules for data+bss.
Also disable misc/cgo/cdefstest since you can't compile C code anymore.
TBR=iant
CC=golang-codereviews
https://golang.org/cl/148050044
In linker, refuse to write conservative (array of pointers) as the
garbage collection type for any variable in the data/bss GC program.
In the linker, attach the Go type to an already-read C declaration
during dedup. This gives us Go types for C globals for free as long
as the cmd/dist-generated Go code contains the declaration.
(Most runtime C declarations have a corresponding Go declaration.
Both are bss declarations and so the linker dedups them.)
In cmd/dist, add a few more C files to the auto-Go-declaration list
in order to get Go type information for the C declarations into the linker.
In C compiler, mark all non-pointer-containing global declarations
and all string data as NOPTR. This allows them to exist in C files
without any corresponding Go declaration. Count C function pointers
as "non-pointer-containing", since we have no heap-allocated C functions.
In runtime, add NOPTR to the remaining pointer-containing declarations,
none of which refer to Go heap objects.
In runtime, also move os.Args and syscall.envs data into runtime-owned
variables. Otherwise, in programs that do not import os or syscall, the
runtime variables named os.Args and syscall.envs will be missing type
information.
I believe that this CL eliminates the final source of conservative GC scanning
in non-SWIG Go programs, and therefore...
Fixes#909.
LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/149770043
Those C files would have been compiled with 6c.
It's close to impossible to use C correctly anymore,
and the C compilers are going away eventually.
Make them unavailable now.
go1.4.txt change in CL 145890046
LGTM=iant
R=iant
CC=golang-codereviews, r
https://golang.org/cl/149720043
Normally, the caller to runtime.entersyscall() must not return before
calling runtime.exitsyscall(), lest g->syscallsp become a dangling
pointer. runtime.cgocallbackg() violates this constraint. To work around
this, save g->syscallsp and g->syscallpc around cgo->Go callbacks, then
restore them after calling runtime.entersyscall(), which restores the
syscall stack frame pointer saved by cgocall. This allows the GC to
correctly trace a goroutine that is currently returning from a
Go->cgo->Go chain.
This also adds a check to proc.c that panics if g->syscallsp is clearly
invalid. It is not 100% foolproof, as it will not catch a case where the
stack was popped then pushed back beyond g->syscallsp, but it does catch
the present cgo issue and makes existing tests fail without the bugfix.
Fixes#7978.
LGTM=dvyukov, rsc
R=golang-codereviews, dvyukov, minux, bradfitz, iant, gobot, rsc
CC=golang-codereviews, rsc
https://golang.org/cl/131910043
Saw this on a test:
runtime: bad pointer in frame runtime_test.testSetPanicOnFault at 0xc20801c6b0: 0xfff
fatal error: bad pointer!
runtime stack:
...
copystack(0xc2081bf7a0, 0x1000)
/root/work/solaris-amd64-smartos-2dde8b453d26/go/src/runtime/stack.c:621 +0x173 fp=0xfffffd7ffd5ffee0 sp=0xfffffd7ffd5ffe20
runtime.newstack()
/root/work/solaris-amd64-smartos-2dde8b453d26/go/src/runtime/stack.c:774 +0x552 fp=0xfffffd7ffd5fff90 sp=0xfffffd7ffd5ffee0
runtime.morestack()
/root/work/solaris-amd64-smartos-2dde8b453d26/go/src/runtime/asm_amd64.s:324 +0x90 fp=0xfffffd7ffd5fff98 sp=0xfffffd7ffd5fff90
goroutine 163354 [stack growth]:
...
runtime.convT2E(0x587000, 0xc20807bea8, 0x0, 0x0)
/root/work/solaris-amd64-smartos-2dde8b453d26/go/src/runtime/iface.go:141 +0xd2 fp=0xc20801c678 sp=0xc20801c640
runtime_test.testSetPanicOnFault(0xc20822c510, 0xfff, 0xc20801c748)
/root/work/solaris-amd64-smartos-2dde8b453d26/go/src/runtime/runtime_test.go:211 +0xc6 fp=0xc20801c718 sp=0xc20801c678
...
This test is testing bad pointers. It loads the bad pointer into a pointer variable,
but before it gets a chance to dereference it, calls convT2E. That call causes a stack copy,
which exposes that live but bad pointer variable.
LGTM=dvyukov
R=golang-codereviews, dvyukov
CC=golang-codereviews
https://golang.org/cl/146880043
When running defers, we must check whether the defer
has already been marked as started so we don't run it twice.
Fixes#8774.
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/142280044
Pure renaming. This will make an upcoming CL have smaller diffs.
LGTM=dvyukov, iant
R=iant, dvyukov
CC=golang-codereviews
https://golang.org/cl/142280043
CL 144940043 renamed it from Sched to SchedType
to avoid a lowercasing conflict in the Go code with
the variable named sched.
We've been using just T resolve those conflicts, not Type.
The FooType pattern is already taken for the kind-specific
variants of the runtime Type structure: ChanType, MapType,
and so on. SchedType isn't a Type.
LGTM=bradfitz, khr
R=khr, bradfitz
CC=golang-codereviews
https://golang.org/cl/145180043
Update #8690
If liblink determines that the host doesn't support TLS it replaces the MRC call with a BL runtime.tls_read_fallback. The problem is save_g doesn't expect anyone to make any BL calls and hasn't setup its own link register properly so when runtime.tls_read_fallback returns the LR points to save_g, not save_g's caller so the RET at the end of the function turns into an infinite loop.
This fix is only a proof of concept, I think the real fix should go into liblink as its MRC substitution is not as transparent as expected.
LGTM=rsc
R=rsc, minux
CC=golang-codereviews
https://golang.org/cl/143050043
We can't assume all those addresses are unmapped.
But at least one should be.
What we're really testing is that the program doesn't crash.
Fixes#8542.
LGTM=iant
R=golang-codereviews, iant, minux
CC=golang-codereviews
https://golang.org/cl/144120043
We mark DBG_PRINTEXCEPTION_C messages in VEH handler
as handled, thus preventing debugger from seeing them.
I don't see reason for doing that. The comment warns
of crashes, but I added test and don't see any crashes.
This is also simplify VEH handler before making
changes to fix issue 8006.
Update #8006
LGTM=rsc
R=golang-codereviews, rsc
CC=golang-codereviews
https://golang.org/cl/146800043
This is to simplify VEH handler before making
changes to fix issue 8006.
Update #8006
LGTM=adg, rsc
R=golang-codereviews, adg, rsc
CC=golang-codereviews
https://golang.org/cl/138630043
Same fix as for SysUnused.
Fixes#8038.
LGTM=iant, alex.brainman
R=golang-codereviews, iant, alex.brainman
CC=golang-codereviews
https://golang.org/cl/147820043
The current Windows build failure happens because by
default runtime frames are excluded from stack traces.
Apparently the Windows breakpoint path dies with an
ordinary panic, while the Unix path dies with a throw.
Breakpoint is a strange function and I don't mind that it's
a little different on the two operating systems.
The panic squelches runtime frames but the throw shows them,
because throw is considered something that shouldn't have
happened at all, so as much detail as possible is wanted.
The runtime exclusion is meant to prevents printing too much noise
about internal runtime details. But exported functions are
not internal details, so show exported functions.
If the program dies because you called runtime.Breakpoint,
it's okay to see that frame.
This makes the Breakpoint test show Breakpoint in the
stack trace no matter how it is handled.
Should fix Windows build.
Tested on Unix by changing Breakpoint to fault instead
of doing a breakpoint.
TBR=brainman
CC=golang-codereviews
https://golang.org/cl/143300043
Since CL 130990043, the GOTRACEBACK variable is
only used when the GODEBUG variable is set.
This change restores the original behavior.
LGTM=rsc
R=golang-codereviews, aram, gobot, r, rsc
CC=golang-codereviews
https://golang.org/cl/132520043
In Go 1.3 the runtime called panicstring to report errors like
divide by zero or memory faults. Now we call panic (gopanic)
with pre-allocated error values. That new path is missing the
checking that panicstring did, so add it there.
The only call to panicstring left is in cnew, which is problematic
because if it fails, probably the heap is corrupt. In that case,
calling panicstring creates a new errorCString (no allocation there),
but then panic tries to print it, invoking errorCString.Error, which
does a string concatenation (allocating), which then dies.
Replace that one panicstring with a throw: cnew is for allocating
runtime data structures and should never ask for an inappropriate
amount of memory.
With panicstring gone, delete newErrorCString, errorCString.
While we're here, delete newErrorString, not called by anyone.
(It can't be: that would be C code calling Go code that might
block or grow the stack.)
Found while debugging a malloc corruption.
This resulted in 'panic during panic' instead of a more useful message.
LGTM=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/138290045
We could probably free the G structures as well, but
for the allg list. Leaving that for another day.
Fixes#8287
LGTM=rsc
R=golang-codereviews, dvyukov, khr, rsc
CC=golang-codereviews
https://golang.org/cl/145010043
The logic here is copied from mgc0.c's scanframe.
Mostly it is messages although the minsize code is new
(and I believe necessary).
I am hoping to get more information about the current
arm build failures (or, if it's the minsize thing, fix them).
TBR=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/143180043
It will be 8K on windows because it needs 4K for the OS.
Similarly, plan9 will be 4K.
On linux/amd64, reduces size of 100,000 goroutines
from ~819MB to ~245MB.
Update #7514
LGTM=dvyukov
R=golang-codereviews, dvyukov, khr, aram
CC=golang-codereviews
https://golang.org/cl/145790043
A Value provides an atomic load and store of a consistently typed value.
It's intended to be used with copy-on-write idiom (see the example).
Performance:
BenchmarkValueRead 50000000 21.7 ns/op
BenchmarkValueRead-2 200000000 8.63 ns/op
BenchmarkValueRead-4 300000000 4.33 ns/op
TBR=rsc
R=golang-codereviews
CC=golang-codereviews
https://golang.org/cl/136710045
semacquire might need to park the currently running G. It can
only park if called from the G stack (because it has no way of
saving the M stack state). So all calls to semacquire must come
from the G stack.
The three violators are GOMAXPROCS, ReadMemStats, and WriteHeapDump.
This change moves the semacquire call earlier, out of their C code
and into their Go code.
This seldom caused bugs because semacquire seldom actually had
to park the caller. But it did happen intermittently.
Fixes#8749
LGTM=dvyukov
R=golang-codereviews, dvyukov, bradfitz
CC=golang-codereviews
https://golang.org/cl/144940043
If this needs to be turned back off, it should be done
just before the '// in finalizer' comment, not at the top
of the function.
GC is more precise now than it was (the only imprecise
stuff left is some global variables), so maybe the finalizer
test will work now on 32-bit systems.
LGTM=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/144030043
If there is a leading ·, assume there is a Go prototype and
attach the Go prototype information to the function.
If the function is not called from Go and does not need a
Go prototype, it can be made file-local instead (using name<>(SB)).
This fixes the current BSD build failures, by giving functions like
sync/atomic.StoreUint32 argument stack map information.
Fixes#8753.
LGTM=khr, iant
R=golang-codereviews, iant, khr, bradfitz
CC=golang-codereviews, r, rlh
https://golang.org/cl/142150043
Along with CLs 139610043 and 141490043,
this removes all conservative scanning during
garbage collection, except _cgo_allocate,
which is SWIG-only.
LGTM=rlh, khr
R=golang-codereviews, dvyukov, rlh, khr
CC=golang-codereviews, iant
https://golang.org/cl/144860043
Now it's two allocations. I don't see much downside to that,
since the two pieces were in different cache lines anyway.
Rename 'conservative' to 'cgo_conservative_type' and make
clear that _cgo_allocate is the only allowed user.
This depends on CL 141490043, which removes the other
use of conservative (in defer).
LGTM=dvyukov, iant
R=khr, dvyukov, iant
CC=golang-codereviews, rlh
https://golang.org/cl/139610043
This makes the GC and the stack copying agree about how
to interpret the defer structures. Previously, only the stack
copying treated them precisely.
This removes an untyped memory allocation and fixes
at least three copystack bugs.
To make sure the GC can find the deferred argument
frame until it has been copied, keep a Defer on the defer list
during its execution.
In addition to making it possible to remove the untyped
memory allocation, keeping the Defer on the list fixes
two races between copystack and execution of defers
(in both gopanic and Goexit). The problem is that once
the defer has been taken off the list, a stack copy that
happens before the deferred arguments have been copied
back to the stack will not update the arguments correctly.
The new tests TestDeferPtrsPanic and TestDeferPtrsGoexit
(variations on the existing TestDeferPtrs) pass now but
failed before this CL.
In addition to those fixes, keeping the Defer on the list
helps correct a dangling pointer error during copystack.
The traceback routines walk the Defer chain to provide
information about where a panic may resume execution.
When the executing Defer was not on the Defer chain
but instead linked from the Panic chain, the traceback
had to walk the Panic chain too. But Panic structs are
on the stack and being updated by copystack.
Traceback's use of the Panic chain while copystack is
updating those structs means that it can follow an
updated pointer and find itself reading from the new stack.
The new stack is usually all zeros, so it sees an incorrect
early end to the chain. The new TestPanicUseStack makes
this happen at tip and dies when adjustdefers finds an
unexpected argp. The new StackCopyPoison mode
causes an earlier bad dereference instead.
By keeping the Defer on the list, traceback can avoid
walking the Panic chain at all, making it okay for copystack
to update the Panics.
We'd have the same problem for any Defers on the stack.
There was only one: gopanic's dabort. Since we are not
taking the executing Defer off the chain, we can use it
to do what dabort was doing, and then there are no
Defers on the stack ever, so it is okay for traceback to use
the Defer chain even while copystack is executing:
copystack cannot modify the Defer chain.
LGTM=khr
R=khr
CC=dvyukov, golang-codereviews, iant, rlh
https://golang.org/cl/141490043
The C header files are the single point of truth:
every C enum constant Foo is available to Go as _Foo.
Remove or redirect duplicate Go declarations so they
cannot be out of sync.
Eventually we will need to put constants in Go, but for now having
them be out of sync with C is too risky. These predate the build
support for auto-generating Go constants from the C definitions.
LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/141510043
I have made mistake while converting it to Go (CL 132820043).
Added test as penance for my sin.
LGTM=rsc
R=golang-codereviews, bradfitz, rsc
CC=golang-codereviews
https://golang.org/cl/136560043
This file was already assigned to another CL
so it didn't make it into the build fix CL. Sigh.
TBR=iant
CC=golang-codereviews
https://golang.org/cl/144850043
This is necessary because syscall.Syscall blocks, and the
garbage collector needs to be able to scan that frame while
it is blocked, and C frames have no garbage collection
information.
Windows builders are broken now due to this problem:
http://build.golang.org/log/152ca9a4be6783d3a8bf6e2f5b9fc265089728b6
LGTM=alex.brainman
R=alex.brainman
CC=golang-codereviews
https://golang.org/cl/144830043
The merged traceback was wrong for LR machines,
because traceback didn't pass lr to gentraceback.
Now that we have a test looking at traceback output
for a trap (the test of runtime.Breakpoint),
we caught this.
While we're here, fix a 'set and not used' warning.
Fixes arm build.
TBR=r
R=r
CC=golang-codereviews
https://golang.org/cl/143040043
It doesn't.
Fixes 386 build.
While we're here, mark runtime.asmcgocall as GO_ARGS,
so that it will work with stack copying. I don't think anything
that uses it can lead to a stack copy, but better safe than sorry.
Certainly the runtime.asmcgocall_errno variant needs
(and already has) GO_ARGS.
TBR=iant
CC=golang-codereviews
https://golang.org/cl/138400043
The argsize PCDATA was specifying the number of
bytes passed to a function call, so that if the function
did not specify its argument count, the garbage collector
could use the call site information to scan those bytes
conservatively. We don't do that anymore, so stop
generating the information.
LGTM=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/139530043
The goal here is to commit fully to having precise information
about stack frames. If we need information we don't have,
crash instead of assuming we should scan conservatively.
Since the stack copying assumes fully precise information,
any crashes during garbage collection that are introduced by
this CL are crashes that could have happened during stack
copying instead. Those are harder to find because stacks are
copied much less often than the garbage collector is invoked.
In service of that goal, remove ARGSIZE macros from
asm_*.s, change switchtoM to have no arguments
(it doesn't have any live arguments), and add
args and locals information to some frames that
can call back into Go.
LGTM=khr
R=khr, rlh
CC=golang-codereviews
https://golang.org/cl/137540043
Dmitriy changed all the execution to interpret the BitVector
as an array of bytes. Update the declaration and generation
of the bitmaps to match, to avoid problems on big-endian
machines.
LGTM=khr
R=khr
CC=dvyukov, golang-codereviews
https://golang.org/cl/140570044
makeFuncStub and methodValueStub are used by reflect as
generic function implementations. Each call might have
different arguments. Extract those arguments from the
closure data instead of assuming it is the same each time.
Because the argument map is now being extracted from the
function itself, we don't need the special cases in reflect.Call
anymore, so delete those.
Fixes an occasional crash seen when stack copying does
not update makeFuncStub's arguments correctly.
Will also help make it safe to require stack maps in the
garbage collector.
Derived from CL 142000044 by khr.
LGTM=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/143890044
The pid field in the Tos structure is a 32-bit value.
Loading a 64-bit word also brings in the next field
which is used for the profiling clock.
LGTM=0intro, aram
R=rsc, 0intro, aram
CC=golang-codereviews, mischief
https://golang.org/cl/139560044
The goal here is to allow assembly functions to appear in the middle
of a Go stack (having called other code) and still record enough information
about their pointers so that stack copying and garbage collection can handle
them precisely. Today, these frames are handled only conservatively.
If you write
func myfunc(x *float64) (y *int)
(with no body, an 'extern' declaration), then the Go compiler now emits
a liveness bitmap for use from the assembly definition of myfunc.
The bitmap symbol is myfunc.args_stackmap and it contains two bitmaps.
The first bitmap, in effect at function entry, marks all inputs as live.
The second bitmap, not in effect at function entry, marks the outputs
live as well.
In funcdata.h, define new assembly macros:
GO_ARGS opts in to using the Go compiler-generated liveness bitmap
for the current function.
GO_RESULTS_INITIALIZED indicates that the results have been initialized
and need to be kept live for the remainder of the function; it causes a
switch to the second generated bitmap for the assembly code that follows.
NO_LOCAL_POINTERS indicates that there are no pointers in the
local variables being stored in the function's stack frame.
LGTM=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/137520043
Tests will come in a separate CL after the funcdata stuff is resolved.
Update #8696
LGTM=iant, rsc
R=rsc, iant
CC=golang-codereviews
https://golang.org/cl/138330045
Just go ahead and do it, if something is wrong we'll throw.
Also rip out cc-generated arg ptr maps, they are useless now.
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/133690045
Replacing gosched with Gosched broke some builds because
some of the call sites are at times when the stack cannot be grown.
TBR=khr
CC=golang-codereviews
https://golang.org/cl/142000043
A write *p = x that needs a write barrier (not all do)
now turns into runtime.writebarrierptr(p, x)
or one of the other variants.
The write barrier implementations are trivial.
The goal here is to emit the calls in the correct places
and to incur the cost of those function calls in the Go 1.4 cycle.
Performance on the Go 1 benchmark suite below.
Remember, the goal is to slow things down (and be correct).
We will look into optimizations in separate CLs, as part of
the process of comparing Go 1.3 against tip in order to make
sure Go 1.4 runs at least as fast as Go 1.3.
benchmark old ns/op new ns/op delta
BenchmarkBinaryTree17 3118336716 3452876110 +10.73%
BenchmarkFannkuch11 3184497677 3211552284 +0.85%
BenchmarkFmtFprintfEmpty 89.9 107 +19.02%
BenchmarkFmtFprintfString 236 287 +21.61%
BenchmarkFmtFprintfInt 246 278 +13.01%
BenchmarkFmtFprintfIntInt 395 458 +15.95%
BenchmarkFmtFprintfPrefixedInt 343 378 +10.20%
BenchmarkFmtFprintfFloat 477 525 +10.06%
BenchmarkFmtManyArgs 1446 1707 +18.05%
BenchmarkGobDecode 14398047 14685958 +2.00%
BenchmarkGobEncode 12557718 12947104 +3.10%
BenchmarkGzip 453462345 472413285 +4.18%
BenchmarkGunzip 114226016 115127398 +0.79%
BenchmarkHTTPClientServer 114689 112122 -2.24%
BenchmarkJSONEncode 24914536 26135942 +4.90%
BenchmarkJSONDecode 86832877 103620289 +19.33%
BenchmarkMandelbrot200 4833452 4898780 +1.35%
BenchmarkGoParse 4317976 4835474 +11.98%
BenchmarkRegexpMatchEasy0_32 150 166 +10.67%
BenchmarkRegexpMatchEasy0_1K 393 402 +2.29%
BenchmarkRegexpMatchEasy1_32 125 142 +13.60%
BenchmarkRegexpMatchEasy1_1K 1010 1236 +22.38%
BenchmarkRegexpMatchMedium_32 232 301 +29.74%
BenchmarkRegexpMatchMedium_1K 76963 102721 +33.47%
BenchmarkRegexpMatchHard_32 3833 5463 +42.53%
BenchmarkRegexpMatchHard_1K 119668 161614 +35.05%
BenchmarkRevcomp 763449047 706768534 -7.42%
BenchmarkTemplate 124954724 134834549 +7.91%
BenchmarkTimeParse 517 511 -1.16%
BenchmarkTimeFormat 501 514 +2.59%
benchmark old MB/s new MB/s speedup
BenchmarkGobDecode 53.31 52.26 0.98x
BenchmarkGobEncode 61.12 59.28 0.97x
BenchmarkGzip 42.79 41.08 0.96x
BenchmarkGunzip 169.88 168.55 0.99x
BenchmarkJSONEncode 77.89 74.25 0.95x
BenchmarkJSONDecode 22.35 18.73 0.84x
BenchmarkGoParse 13.41 11.98 0.89x
BenchmarkRegexpMatchEasy0_32 213.30 191.72 0.90x
BenchmarkRegexpMatchEasy0_1K 2603.92 2542.74 0.98x
BenchmarkRegexpMatchEasy1_32 254.00 224.93 0.89x
BenchmarkRegexpMatchEasy1_1K 1013.53 827.98 0.82x
BenchmarkRegexpMatchMedium_32 4.30 3.31 0.77x
BenchmarkRegexpMatchMedium_1K 13.30 9.97 0.75x
BenchmarkRegexpMatchHard_32 8.35 5.86 0.70x
BenchmarkRegexpMatchHard_1K 8.56 6.34 0.74x
BenchmarkRevcomp 332.92 359.62 1.08x
BenchmarkTemplate 15.53 14.39 0.93x
LGTM=rlh
R=rlh
CC=dvyukov, golang-codereviews, iant, khr, r
https://golang.org/cl/136380043
The uses of onM in dopanic/startpanic are okay even from the signal stack.
Fixes#8666.
LGTM=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/134710043
They will both need write barriers at some point.
But until then, no reason why we shouldn't share.
LGTM=rsc
R=golang-codereviews, rsc
CC=golang-codereviews
https://golang.org/cl/141330043
The previous implementation had several subtle issues. It's not
clear if any of these could actually be causing the flakiness
problems on openbsd/386, but fixing them should only help.
1. thrsleep() is implemented internally as unlock, then test *abort
(if abort != nil), then tsleep(). Under the current code, that makes
it theoretically possible that semasleep()/thrsleep() could release
waitsemalock, then a racing semawakeup() could acquire the lock,
increment waitsemacount, and call thrwakeup()/wakeup() before
thrsleep() reaches tsleep(). (In practice, OpenBSD's big kernel lock
seems unlikely to let this actually happen.)
The proper way to avoid this is to pass &waitsemacount as the abort
pointer to thrsleep so thrsleep knows to re-check it before going to
sleep, and to wakeup if it's non-zero. Then we avoid any races.
(I actually suspect openbsd's sema{sleep,wakeup}() could be further
simplified using cas/xadd instead of locks, but I don't want to be
more intrusive than necessary so late in the 1.4 release cycle.)
2. semasleep() takes a relative sleep duration, but thrsleep() needs
an absolute sleep deadline. Instead of recomputing the deadline each
iteration, compute it once up front and use (*Timespec)(nil) to signify
no deadline. Ensures we retry properly if there's a spurious wakeup.
3. Instead of assuming if thrsleep() woke up and waitsemacount wasn't
available that we must have hit the deadline, check that the system
call returned EWOULDBLOCK.
4. Instead of assuming that 64-bit systems are little-endian, compute
timediv() using a temporary int32 nsec and then assign it to tv_nsec.
LGTM=iant
R=jsing, iant
CC=golang-codereviews
https://golang.org/cl/137960043
A race exists between the parent and child processes after a fork.
The child needs to access the new M pointer passed as an argument
but the parent may have already returned and clobbered it.
Previously, we avoided this by saving the necessary data into
registers before the rfork system call but this isn't guaranteed
to work because Plan 9 makes no promises about the register state
after a system call. Only the 386 kernel seems to save them.
For amd64 and arm, this method won't work.
We eliminate the race by allocating stack space for the scheduler
goroutines (g0) in the per-process copy-on-write stack segment and
by only calling rfork on the scheduler stack.
LGTM=aram, 0intro, rsc
R=aram, 0intro, mischief, rsc
CC=golang-codereviews
https://golang.org/cl/110680044
The only thing I can see that is really Plan 9-specific
is that the stack pointer used for signal handling used
to have more mapped memory above it.
Specifically it used to have at most 88 bytes (StackTop),
so change the allocation of a 40-byte frame to a 128-byte frame.
No idea if this will work, but worth a try.
Note that "fix" here means get it back to timing out
instead of crashing.
TBR=iant
CC=golang-codereviews
https://golang.org/cl/142840043
The difference between the old and the new (from earlier) code
is that we set stackguard = stack.lo + StackGuard, while the old
code set stackguard = stack.lo. That 512 bytes appears to be
the difference between the profileloop function running and not running.
We don't know how big the system stack is, but it is likely MUCH bigger than 4k.
Give Go/C 8k.
TBR=iant
CC=golang-codereviews
https://golang.org/cl/140440044
Start the stack a few words below the actual top, so that
if something tries to read goexit's caller PC from the stack,
it won't fault on a bad memory address.
Today, heapdump does that.
Maybe tomorrow, traceback or something else will do that.
Make it not a bug.
TBR=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/136450043
Commit to stack copying for stack growth.
We're carrying around a surprising amount of cruft from older schemes.
I am confident that precise stack scans and stack copying are here to stay.
Delete fallback code for when precise stack info is disabled.
Delete fallback code for when copying stacks is disabled.
Delete fallback code for when StackCopyAlways is disabled.
Delete Stktop chain - there is only one stack segment now.
Delete M.moreargp, M.moreargsize, M.moreframesize, M.cret.
Delete G.writenbuf (unrelated, just dead).
Delete runtime.lessstack, runtime.oldstack.
Delete many amd64 morestack variants.
Delete initialization of morestack frame/arg sizes (shortens split prologue!).
Replace G's stackguard/stackbase/stack0/stacksize/
syscallstack/syscallguard/forkstackguard with simple stack
bounds (lo, hi).
Update liblink, runtime/cgo for adjustments to G.
LGTM=khr
R=khr, bradfitz
CC=golang-codereviews, iant, r
https://golang.org/cl/137410043
I have found better approach, then longer wait.
See CL 134360043 for details.
««« original CL description
runtime/pprof: adjust cpuHogger so that tests pass on windows builders
LGTM=rsc
R=dvyukov, rsc
CC=golang-codereviews
https://golang.org/cl/140110043
»»»
LGTM=dave
R=golang-codereviews, dave, dvyukov
CC=golang-codereviews
https://golang.org/cl/133500043
I assumed they were the same when I wrote
cgocallback.go earlier today. Merge them
to eliminate confusion.
I can't tell what gomallocgc did before with
a nil type but without FlagNoScan.
I created a call like that in cgocallback.go
this morning, translating from a C file.
It was supposed to do what the C version did,
namely treat the block conservatively.
Now it will.
LGTM=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/141810043
It already is updating parts of them; we're just getting lucky
retraversing them and not finding much to do.
Change argp to a pointer so that it will be updated too.
Existing tests break if you apply the change to adjustpanics
without also updating the type of argp.
LGTM=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/139380043
It worked at CL 134660043 on the builders,
so I believe it will stick this time.
LGTM=bradfitz
R=khr, bradfitz
CC=golang-codereviews
https://golang.org/cl/141280043
This should make deferreturn nosplit all the way down,
which should fix the current windows/amd64 failure.
If not, I will change StackCopyAlways back to 0.
TBR=khr
CC=golang-codereviews
https://golang.org/cl/135600043
Let's see how close we are to this being ready.
Will roll back if it breaks any builds in non-trivial ways.
LGTM=r, khr
R=iant, khr, r
CC=golang-codereviews
https://golang.org/cl/138200043
The sighander has been run at the bottom of the
currently executing goroutine stack, but it's in C,
and we don't want C on our ordinary goroutine stacks.
Worse, it does a lot of stuff, and it might need more
stack space. There is scary code in traceback_windows.go
that talks about stack splits during sighandler.
Moving sighandler to g0 will eliminate the possibility
of stack splits and such, and then we can delete
traceback_windows.go entirely. Win win.
On the builder, all.bat passes with GOARCH=amd64
and all.bat gets most of the way with GOARCH=386
except for a DLL-loading test that I think is unrelated.
Fixes windows build.
TBR=brainman, iant
CC=golang-codereviews
https://golang.org/cl/140380043
This CL contains compiler+runtime changes that detect C code
running on Go (not g0, not gsignal) stacks, and it contains
corrections for what it detected.
The detection works by changing the C prologue to use a different
stack guard word in the G than Go prologue does. On the g0 and
gsignal stacks, that stack guard word is set to the usual
stack guard value. But on ordinary Go stacks, that stack
guard word is set to ^0, which will make any stack split
check fail. The C prologue then calls morestackc instead
of morestack, and morestackc aborts the program with
a message about running C code on a Go stack.
This check catches all C code running on the Go stack
except NOSPLIT code. The NOSPLIT code is allowed,
so the check is complete. Since it is a dynamic check,
the code must execute to be caught. But unlike the static
checks we've been using in cmd/ld, the dynamic check
works with function pointers and other indirect calls.
For example it caught sigpanic being pushed onto Go
stacks in the signal handlers.
Fixes#8667.
LGTM=khr, iant
R=golang-codereviews, khr, iant
CC=golang-codereviews, r
https://golang.org/cl/133700043
avoid tight coupling between deferreturn and jmpdefer.
before, jmpdefer knew the exact frame size of deferreturn
in order to pop it off the stack. now, deferreturn passes
jmpdefer a pointer to the frame above it explicitly.
that avoids a magic constant and should be less fragile.
R=r
DELTA=32 (6 added, 3 deleted, 23 changed)
OCL=29801
CL=29804
The code was already careful not to use malloc/free
for stack growth during calls to malloc.
Avoid them during calls to free too.
R=r
DELTA=9 (7 added, 0 deleted, 2 changed)
OCL=29606
CL=29610
