getcallersp is intrinsified, and so the dummy arg is no longer
needed. Remove it, as well as a few dummy args that are solely
to feed getcallersp.
Change-Id: Ibb6c948ff9c56537042b380ac3be3a91b247aaa6
Reviewed-on: https://go-review.googlesource.com/109596
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Now that getcallerpc is a compiler intrinsic on x86 and non-x86
platforms don't need the argument, we can drop it.
Sadly, this doesn't let us remove any dummy arguments since all of
those cases also use getcallersp, which still takes the argument
pointer, but this is at least an improvement.
Change-Id: I9c34a41cf2c18cba57f59938390bf9491efb22d2
Reviewed-on: https://go-review.googlesource.com/65474
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Currently runtime.GC() triggers a STW GC. For common uses in tests and
benchmarks, it doesn't matter whether it's STW or concurrent, but for
uses in servers for things like collecting heap profiles and
controlling memory footprint, this pause can be a bit problem for
latency.
This changes runtime.GC() to trigger a concurrent GC. In order to
remain as close as possible to its current meaning, we define it to
always perform a full mark/sweep GC cycle before returning (even if
that means it has to finish up a cycle we're in the middle of first)
and to publish the heap profile as of the triggered mark termination.
While it must perform a full cycle, simultaneous runtime.GC() calls
can be consolidated into a single full cycle.
Fixes#18216.
Change-Id: I9088cc5deef4ab6bcf0245ed1982a852a01c44b5
Reviewed-on: https://go-review.googlesource.com/37520
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
Currently we snapshot the heap profile just *after* mark termination
starts the world because it's a relatively expensive operation.
However, this means any alloc or free events that happen between
starting the world and snapshotting the heap profile can be accounted
to the wrong cycle. In the worst case, a free can be accounted to the
cycle before the alloc; if the heap is small, this can result
temporarily in a negative "in use" count in the profile.
Fix this without making STW more expensive by using a global heap
profile cycle counter. This lets us split up the operation into a two
parts: 1) a super-cheap snapshot operation that simply increments the
global cycle counter during STW, and 2) a more expensive cleanup
operation we can do after starting the world that frees up a slot in
all buckets for use by the next heap profile cycle.
Fixes#19311.
Change-Id: I6bdafabf111c48b3d26fe2d91267f7bef0bd4270
Reviewed-on: https://go-review.googlesource.com/37714
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
Currently memRecord has the same set of four fields repeated three
times. Pull these into a type and use this type three times. This
cleans up and simplifies the code a bit and will make it easier to
switch to a globally tracked heap profile cycle for #19311.
Change-Id: I414d15673feaa406a8366b48784437c642997cf2
Reviewed-on: https://go-review.googlesource.com/37713
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
Every time I modify heap profiling, I find myself redrawing this
diagram, so add it to the comments. This shows how allocations and
frees are accounted, how we arrive at consistent profile snapshots,
and when those snapshots are published to the user.
Change-Id: I106aba1200af3c773b46e24e5f50205e808e2c69
Reviewed-on: https://go-review.googlesource.com/37514
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
Found by github.com/mvdan/unparam.
Change-Id: Iabcdfec2ae42c735aa23210b7183080d750682ca
Reviewed-on: https://go-review.googlesource.com/38030
Reviewed-by: Peter Weinberger <pjw@google.com>
Run-TryBot: Peter Weinberger <pjw@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
On solaris/amd64 sometimes the reported cycle count is negative. Replace
with 0.
Change-Id: I364eea5ca072281245c7ab3afb0bf69adc3a8eae
Reviewed-on: https://go-review.googlesource.com/32258
Reviewed-by: Ian Lance Taylor <iant@golang.org>
runtime.SetMutexProfileFraction(n int) will capture 1/n-th of stack
traces of goroutines holding contended mutexes if n > 0. From runtime/pprof,
pprot.Lookup("mutex").WriteTo writes the accumulated
stack traces to w (in essentially the same format that blocking
profiling uses).
Change-Id: Ie0b54fa4226853d99aa42c14cb529ae586a8335a
Reviewed-on: https://go-review.googlesource.com/29650
Reviewed-by: Austin Clements <austin@google.com>
This covers basically all sysAlloc'd, persistentalloc'd, and
fixalloc'd types.
Change-Id: I0487c887c2a0ade5e33d4c4c12d837e97468e66b
Reviewed-on: https://go-review.googlesource.com/30941
Reviewed-by: Rick Hudson <rlh@golang.org>
Instrumenting copy and append for the race detector changes them to call
different functions. In the runtime package the alternate functions are
not marked as nosplit. This caused a crash in the SIGPROF handler when
invoked on a non-Go thread in a program built with the race detector. In
some cases the handler can call copy, the race detector changed that to
a call to a non-nosplit function, the function tried to check the stack
guard, and crashed because it was running on a non-Go thread. The
SIGPROF handler is written carefully to avoid such problems, but hidden
function calls are difficult to avoid.
Fix this by changing the compiler to not instrument copy and append when
compiling the runtime package. Change the runtime package to add
explicit race checks for the only code I could find where copy is used
to write to user data (append is never used).
Change-Id: I11078a66c0aaa459a7d2b827b49f4147922050af
Reviewed-on: https://go-review.googlesource.com/29472
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
The tree's pretty inconsistent about single space vs double space
after a period in documentation. Make it consistently a single space,
per earlier decisions. This means contributors won't be confused by
misleading precedence.
This CL doesn't use go/doc to parse. It only addresses // comments.
It was generated with:
$ perl -i -npe 's,^(\s*// .+[a-z]\.) +([A-Z]),$1 $2,' $(git grep -l -E '^\s*//(.+\.) +([A-Z])')
$ go test go/doc -update
Change-Id: Iccdb99c37c797ef1f804a94b22ba5ee4b500c4f7
Reviewed-on: https://go-review.googlesource.com/20022
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Dave Day <djd@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The previous CL is the real fix. This one is just insurance.
Fixes#14046 again.
Change-Id: I553349504bb1789e4b66c888dbe4034568918ad6
Reviewed-on: https://go-review.googlesource.com/18977
Reviewed-by: Austin Clements <austin@google.com>
It was just completely broken if you gave it the number
of records it asked for. Make it impossible for that particular
inconsistency to happen again.
Also make it exclude system goroutines, to match both
NumGoroutine and Stack.
Fixes#14046.
Change-Id: Ic238c6b89934ba7b47cccd3440dd347ed11e4c3d
Reviewed-on: https://go-review.googlesource.com/18976
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
[Repeat of CL 18343 with build fixes.]
Before, NumGoroutine counted system goroutines and Stack (usually) didn't show them,
which was inconsistent and confusing.
To resolve which way they should be consistent, it seems like
package main
import "runtime"
func main() { println(runtime.NumGoroutine()) }
should print 1 regardless of internal runtime details. Make it so.
Fixes#11706.
Change-Id: If26749fec06aa0ff84311f7941b88d140552e81d
Reviewed-on: https://go-review.googlesource.com/18432
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Russ Cox <rsc@golang.org>
Before, NumGoroutine counted system goroutines and Stack (usually) didn't show them,
which was inconsistent and confusing.
To resolve which way they should be consistent, it seems like
package main
import "runtime"
func main() { println(runtime.NumGoroutine()) }
should print 1 regardless of internal runtime details. Make it so.
Fixes#11706.
Change-Id: I6bfe26a901de517728192cfb26a5568c4ef4fe47
Reviewed-on: https://go-review.googlesource.com/18343
Reviewed-by: Austin Clements <austin@google.com>
This change breaks out most of the atomics functions in the runtime
into package runtime/internal/atomic. It adds some basic support
in the toolchain for runtime packages, and also modifies linux/arm
atomics to remove the dependency on the runtime's mutex. The mutexes
have been replaced with spinlocks.
all trybots are happy!
In addition to the trybots, I've tested on the darwin/arm64 builder,
on the darwin/arm builder, and on a ppc64le machine.
Change-Id: I6698c8e3cf3834f55ce5824059f44d00dc8e3c2f
Reviewed-on: https://go-review.googlesource.com/14204
Run-TryBot: Michael Matloob <matloob@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
There are several steps to stopping and starting the world and
currently they're open-coded in several places. The garbage collector
is the only thing that needs to stop and start the world in a
non-trivial pattern. Replace all other uses with calls to higher-level
functions that implement the entire pattern necessary to stop and
start the world.
This is a pure refectoring and should not change any code semantics.
In the following commits, we'll make changes that are easier to do
with this abstraction in place.
This commit renames the old starttheworld to startTheWorldWithSema.
This is a slight misnomer right now because the callers release
worldsema just before calling this. However, a later commit will swap
these and I don't want to think of another name in the mean time.
Change-Id: I5dc97f87b44fb98963c49c777d7053653974c911
Reviewed-on: https://go-review.googlesource.com/10154
Reviewed-by: Russ Cox <rsc@golang.org>
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>
m.gcing has become overloaded to mean "don't preempt this g" in
general. Once the garbage collector is preemptible, the one thing it
*won't* mean is that we're in the garbage collector.
So, rename gcing to "preemptoff" and make it a string giving a reason
that preemption is disabled. gcing was never set to anything but 0 or
1, so we don't have to worry about there being a stack of reasons.
Change-Id: I4337c29e8e942e7aa4f106fc29597e1b5de4ef46
Reviewed-on: https://go-review.googlesource.com/3660
Reviewed-by: Russ Cox <rsc@golang.org>
Rename "gothrow" to "throw" now that the C version of "throw"
is no longer needed.
This change is purely mechanical except in panic.go where the
old version of "throw" has been deleted.
sed -i "" 's/[[:<:]]gothrow[[:>:]]/throw/g' runtime/*.go
Change-Id: Icf0752299c35958b92870a97111c67bcd9159dc3
Reviewed-on: https://go-review.googlesource.com/2150
Reviewed-by: Minux Ma <minux@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>
It shouldn't semacquire() inside an acquirem(), the runtime
thinks that means deadlock. It actually isn't a deadlock, but it
looks like it because acquirem() does m.locks++.
Candidate for inclusion in 1.4.1. runtime.Stack with all=true
is pretty unuseable in GOMAXPROCS>1 environment.
fixes#9321
Change-Id: Iac6b664217d24763b9878c20e49229a1ecffc805
Reviewed-on: https://go-review.googlesource.com/1600
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Scalararg and ptrarg are not "signal safe".
Go code filling them out can be interrupted by a signal,
and then the signal handler runs, and if it also ends up
in Go code that uses scalararg or ptrarg, now the old
values have been smashed.
For the pieces of code that do need to run in a signal handler,
we introduced onM_signalok, which is really just onM
except that the _signalok is meant to convey that the caller
asserts that scalarg and ptrarg will be restored to their old
values after the call (instead of the usual behavior, zeroing them).
Scalararg and ptrarg are also untyped and therefore error-prone.
Go code can always pass a closure instead of using scalararg
and ptrarg; they were only really necessary for C code.
And there's no more C code.
For all these reasons, delete scalararg and ptrarg, converting
the few remaining references to use closures.
Once those are gone, there is no need for a distinction between
onM and onM_signalok, so replace both with a single function
equivalent to the current onM_signalok (that is, it can be called
on any of the curg, g0, and gsignal stacks).
The name onM and the phrase 'm stack' are misnomers,
because on most system an M has two system stacks:
the main thread stack and the signal handling stack.
Correct the misnomer by naming the replacement function systemstack.
Fix a few references to "M stack" in code.
The main motivation for this change is to eliminate scalararg/ptrarg.
Rick and I have already seen them cause problems because
the calling sequence m.ptrarg[0] = p is a heap pointer assignment,
so it gets a write barrier. The write barrier also uses onM, so it has
all the same problems as if it were being invoked by a signal handler.
We worked around this by saving and restoring the old values
and by calling onM_signalok, but there's no point in keeping this nice
home for bugs around any longer.
This CL also changes funcline to return the file name as a result
instead of filling in a passed-in *string. (The *string signature is
left over from when the code was written in and called from C.)
That's arguably an unrelated change, except that once I had done
the ptrarg/scalararg/onM cleanup I started getting false positives
about the *string argument escaping (not allowed in package runtime).
The compiler is wrong, but the easiest fix is to write the code like
Go code instead of like C code. I am a bit worried that the compiler
is wrong because of some use of uninitialized memory in the escape
analysis. If that's the reason, it will go away when we convert the
compiler to Go. (And if not, we'll debug it the next time.)
LGTM=khr
R=r, khr
CC=austin, golang-codereviews, iant, rlh
https://golang.org/cl/174950043
The conversion was done with an automated tool and then
modified only as necessary to make it compile and run.
[This CL is part of the removal of C code from package runtime.
See golang.org/s/dev.cc for an overview.]
LGTM=r
R=r
CC=austin, dvyukov, golang-codereviews, iant, khr
https://golang.org/cl/167540043
Gentraceback may grow the stack.
One of the gentraceback wrappers may grow the stack.
One of the gentraceback callback calls may grow the stack.
Various stack pointers are stored in various stack locations
as type uintptr during the execution of these calls.
If the stack does grow, these stack pointers will not be
updated and will start trying to decode stack memory that
is no longer valid.
It may be possible to change the type of the stack pointer
variables to be unsafe.Pointer, but that's pretty subtle and
may still have problems, even if we catch every last one.
An easier, more obviously correct fix is to require that
gentraceback of the currently running goroutine must run
on the g0 stack, not on the goroutine's own stack.
Not doing this causes faults when you set
StackFromSystem = 1
StackFaultOnFree = 1
The new check in gentraceback will catch future lapses.
The more general problem is calling getcallersp but then
calling a function that might relocate the stack, which would
invalidate the result of getcallersp. Add note to stubs.go
declaration of getcallersp explaining the problem, and
check all existing calls to getcallersp. Most needed fixes.
This affects Callers, Stack, and nearly all the runtime
profiling routines. It does not affect stack copying directly
nor garbage collection.
LGTM=khr
R=khr, bradfitz
CC=golang-codereviews, r
https://golang.org/cl/167060043
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
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
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
