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2022-09-01Revert "runtime: convert ncgocall to atomic type"Michael Pratt
This reverts CL 426075. Reason for revert: Import missing from cgocall.go. Change-Id: Iac17e914045b83da30484dbe2a624cde526fb175 Reviewed-on: https://go-review.googlesource.com/c/go/+/427614 Reviewed-by: Heschi Kreinick <heschi@google.com>
2022-09-01runtime: convert ncgocall to atomic typecuiweixie
For #53821 Change-Id: Ib0d62ee36487b3ed68e063976968f3cac6499e4b Reviewed-on: https://go-review.googlesource.com/c/go/+/426075 Reviewed-by: Michael Pratt <mpratt@google.com> Run-TryBot: xie cui <523516579@qq.com> Reviewed-by: Heschi Kreinick <heschi@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
2022-08-02runtime: trivial replacements of g in remaining filesMichael Pratt
Rename g variables to gp for consistency. Change-Id: I09ecdc7e8439637bc0e32f9c5f96f515e6436362 Reviewed-on: https://go-review.googlesource.com/c/go/+/418591 Reviewed-by: Austin Clements <austin@google.com> Run-TryBot: Michael Pratt <mpratt@google.com>
2022-04-11all: gofmt main repoRuss Cox
[This CL is part of a sequence implementing the proposal #51082. The design doc is at https://go.dev/s/godocfmt-design.] Run the updated gofmt, which reformats doc comments, on the main repository. Vendored files are excluded. For #51082. Change-Id: I7332f099b60f716295fb34719c98c04eb1a85407 Reviewed-on: https://go-review.googlesource.com/c/go/+/384268 Reviewed-by: Jonathan Amsterdam <jba@google.com> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2021-11-05runtime: add a maymorestack hook that moves the stackAustin Clements
This adds a maymorestack hook that moves the stack at every cooperative preemption point. For #48297. Change-Id: Ic15f9bcbc163345e6422586302d57fda4744caec Reviewed-on: https://go-review.googlesource.com/c/go/+/359797 Trust: Austin Clements <austin@google.com> Run-TryBot: Austin Clements <austin@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Cherry Mui <cherryyz@google.com> Reviewed-by: Michael Pratt <mpratt@google.com> Reviewed-by: David Chase <drchase@google.com>
2021-11-05runtime: add always-preempt maymorestack hookAustin Clements
This adds a maymorestack hook that forces a preemption at every possible cooperative preemption point. This would have helped us catch several recent preemption-related bugs earlier, including #47302, #47304, and #47441. For #48297. Change-Id: Ib82c973589c8a7223900e1842913b8591938fb9f Reviewed-on: https://go-review.googlesource.com/c/go/+/359796 Trust: Austin Clements <austin@google.com> Run-TryBot: Austin Clements <austin@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Cherry Mui <cherryyz@google.com> Reviewed-by: Michael Pratt <mpratt@google.com> Reviewed-by: David Chase <drchase@google.com>
2021-06-25runtime: make ncgocall a global counterTao Qingyun
ncgocall was stored per M, runtime.NumCgoCall lost the counter when a M die. Fixes #46789 Change-Id: I85831fbb2713f4c30d1800d07e1f47aa0031970e GitHub-Last-Rev: cbc15fa870de776d3fbf3b62fc9a5e01792e6a26 GitHub-Pull-Request: golang/go#46842 Reviewed-on: https://go-review.googlesource.com/c/go/+/329729 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org> Trust: Alexander Rakoczy <alex@golang.org>
2020-09-10runtime: update docs for GOMAXPROCSipriver
https://github.com/golang/go/blob/master/doc/effective_go.html#L3211 is used to update the docs comment for `GOMAXPROCS` function. Fixes #41275 Change-Id: I39f58e93a267c6e9f3ac6638ed51acbe5284ada2 GitHub-Last-Rev: e45c8ac5873979397d747838fd8d41e252aec489 GitHub-Pull-Request: golang/go#41276 Reviewed-on: https://go-review.googlesource.com/c/go/+/253537 Reviewed-by: Keith Randall <khr@golang.org>
2020-03-18runtime: don't hold worldsema across mark phaseMichael Anthony Knyszek
This change makes it so that worldsema isn't held across the mark phase. This means that various operations like ReadMemStats may now stop the world during the mark phase, reducing latency on such operations. Only three such operations are still no longer allowed to occur during marking: GOMAXPROCS, StartTrace, and StopTrace. For the former it's because any change to GOMAXPROCS impacts GC mark background worker scheduling and the details there are tricky. For the latter two it's because tracing needs to observe consistent GC start and GC end events, and if StartTrace or StopTrace may stop the world during marking, then it's possible for it to see a GC end event without a start or GC start event without an end, respectively. To ensure that GOMAXPROCS and StartTrace/StopTrace cannot proceed until marking is complete, the runtime now holds a new semaphore, gcsema, across the mark phase just like it used to with worldsema. This change is being landed once more after being reverted in the Go 1.14 release cycle, since CL 215157 allows it to have a positive effect on system performance. For the benchmark BenchmarkReadMemStatsLatency in the runtime, which measures ReadMemStats latencies while the GC is exercised, the tail of these latencies reduced dramatically on an 8-core machine: name old 50%tile-ns new 50%tile-ns delta ReadMemStatsLatency-8 4.40M ±74% 0.12M ± 2% -97.35% (p=0.008 n=5+5) name old 90%tile-ns new 90%tile-ns delta ReadMemStatsLatency-8 102M ± 6% 0M ±14% -99.79% (p=0.008 n=5+5) name old 99%tile-ns new 99%tile-ns delta ReadMemStatsLatency-8 147M ±18% 4M ±57% -97.43% (p=0.008 n=5+5) Fixes #19812. Change-Id: If66c3c97d171524ae29f0e7af4bd33509d9fd0bb Reviewed-on: https://go-review.googlesource.com/c/go/+/216557 Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-01-24Revert "runtime: don't hold worldsema across mark phase"Michael Knyszek
This reverts commit 7b294cdd8df0a9523010f6ffc80c59e64578f34b, CL 182657. Reason for revert: This change may be causing latency problems for applications which call ReadMemStats, because it may cause all goroutines to stop until the GC completes. https://golang.org/cl/215157 fixes this problem, but it's too late in the cycle to land that. Updates #19812. Change-Id: Iaa26f4dec9b06b9db2a771a44e45f58d0aa8f26d Reviewed-on: https://go-review.googlesource.com/c/go/+/216358 Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com>
2019-09-04runtime: don't hold worldsema across mark phaseMichael Anthony Knyszek
This change makes it so that worldsema isn't held across the mark phase. This means that various operations like ReadMemStats may now stop the world during the mark phase, reducing latency on such operations. Only three such operations are still no longer allowed to occur during marking: GOMAXPROCS, StartTrace, and StopTrace. For the former it's because any change to GOMAXPROCS impacts GC mark background worker scheduling and the details there are tricky. For the latter two it's because tracing needs to observe consistent GC start and GC end events, and if StartTrace or StopTrace may stop the world during marking, then it's possible for it to see a GC end event without a start or GC start event without an end, respectively. To ensure that GOMAXPROCS and StartTrace/StopTrace cannot proceed until marking is complete, the runtime now holds a new semaphore, gcsema, across the mark phase just like it used to with worldsema. Fixes #19812. Change-Id: I15d43ed184f711b3d104e8f267fb86e335f86bf9 Reviewed-on: https://go-review.googlesource.com/c/go/+/182657 Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com>
2019-04-23cmd/go: move runtime/debug.modinfo to runtime.modinfoRuss Cox
It is easier to ensure that the symbol is always present if we move it to package runtime. Avoids init-time work. Also moves it next to buildVersion, the other similar symbol. Setting up for "go version <binary>". For #31624. Change-Id: I943724469ce6992153e701257eb6f12da88c8e4e Reviewed-on: https://go-review.googlesource.com/c/go/+/173341 Run-TryBot: Russ Cox <rsc@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-05-08runtime: add js/wasm architectureRichard Musiol
This commit adds the js/wasm architecture to the runtime package. Currently WebAssembly has no support for threads yet, see https://github.com/WebAssembly/design/issues/1073. Because of that, there is no preemption of goroutines and no sysmon goroutine. Design doc: https://docs.google.com/document/d/131vjr4DH6JFnb-blm_uRdaC0_Nv3OUwjEY5qVCxCup4 About WebAssembly assembly files: https://docs.google.com/document/d/1GRmy3rA4DiYtBlX-I1Jr_iHykbX8EixC3Mq0TCYqbKc Updates #18892 Change-Id: I7f12d21b5180500d55ae9fd2f7e926a1731db391 Reviewed-on: https://go-review.googlesource.com/103877 Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Austin Clements <austin@google.com>
2017-09-27runtime: eliminate GOMAXPROCS limitAustin Clements
Now that allp is dynamically allocated, there's no need for a hard cap on GOMAXPROCS. Fixes #15131. Change-Id: I53eee8e228a711a818f7ebce8d9fd915b3865eed Reviewed-on: https://go-review.googlesource.com/45574 Run-TryBot: Austin Clements <austin@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Rick Hudson <rlh@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-03-02all: single space after period.Brad Fitzpatrick
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>
2015-12-05runtime: document that NumCPU does not changeRuss Cox
Fixes #11609. Change-Id: I3cf64164fde28ebf739706728b84d8ef5b6dc90e Reviewed-on: https://go-review.googlesource.com/17456 Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-11-10runtime: break atomics out into package runtime/internal/atomicMichael Matloob
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>
2015-07-10runtime: clarify that NumCPU returns only available CPUsIan Lance Taylor
Update #11609. Change-Id: Ie363facf13f5e62f1af4a8bdc42a18fb36e16ebf Reviewed-on: https://go-review.googlesource.com/12022 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-05-18runtime: factor stoptheworld/starttheworld patternAustin Clements
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>
2015-02-02runtime: rename m.gcing to m.preemptoff and make it a stringAustin Clements
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>
2014-11-12[dev.cc] runtime: delete scalararg, ptrarg; rename onM to systemstackRuss Cox
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
2014-11-11[dev.cc] runtime: convert scheduler from C to GoRuss Cox
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, daniel.morsing CC=austin, dvyukov, golang-codereviews, iant, khr https://golang.org/cl/172260043
2014-09-16runtime: always run semacquire on the G stackKeith Randall
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
2014-09-08build: move package sources from src/pkg to srcRuss Cox
Preparation was in CL 134570043. This CL contains only the effect of 'hg mv src/pkg/* src'. For more about the move, see golang.org/s/go14nopkg.