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2026-01-08runtime/trace: fix documentation commentjjpinto
Correct documentation comment for mul function Change-Id: I8b90f02bf0aaba9bb5813833d1b9dd1ebb7d71f4 GitHub-Last-Rev: e91af64af9bad9cd2574dc3dd7ed88123a288be8 GitHub-Pull-Request: golang/go#77082 Reviewed-on: https://go-review.googlesource.com/c/go/+/734100 Reviewed-by: Michael Knyszek <mknyszek@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Michael Pratt <mpratt@google.com>
2026-01-07internal/trace: fix recorder.Write return value for header-only buffersjjpinto
Fix issue #77083 Change-Id: I9189d1e3a6efea8478224164e820f50c818abcd5 GitHub-Last-Rev: bb24cbda95f0b5b10aeae9a5ee8cbe215ba6d4eb GitHub-Pull-Request: golang/go#77092 Reviewed-on: https://go-review.googlesource.com/c/go/+/734300 Reviewed-by: Michael Pratt <mpratt@google.com> Reviewed-by: Michael Knyszek <mknyszek@google.com> Commit-Queue: Michael Knyszek <mknyszek@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2025-12-12runtime: dropg after emitting trace event in preemptParkMichael Anthony Knyszek
Because we dropg before emitting a trace event in preemptPark, we end up failing to emit a status for the goroutine if this happens to be the first event for it in the generation. We only really see this with multiple subscribers in TestSubscribers. This is for two reasons: 1. If we are missing a status event for a non-initial generation then the trace parser won't validate that (an oversight, but we can only enforce that for new traces because of this bug), and 2. If we're starting the tracer fresh, then we have a STW which effectively guarantees that the first event for a goroutine cannot come from preemptPark. Therefore, we cannot observe this situation unless the first generation manifests the bug, but prior to having flight recording and/or multiple subscribers being able to "cut" the trace data at any point, this was impossible. The fix is simple: dropg only after emitting the trace event. This is also safe, because the tracer doesn't care. The tracer will also start taking a stack trace of the goroutine in this circumstance, but that is also safe, since we are able to generally unwind the stack of asynchronously preempted goroutines, and here we're at the very, very end of asynchronous preemption where all the state to do so is already set up. Fixes #75665. Change-Id: I7ee1142697d0a53b62d4c5647aa53775d2f6976a Reviewed-on: https://go-review.googlesource.com/c/go/+/729400 LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Cherry Mui <cherryyz@google.com>
2025-12-11runtime/trace: fix broken TestSubscribersMichael Anthony Knyszek
Currently we don't break out of the loop on a failure. This is leading to timeouts trying to parse a broken trace over and over, forever. But there's another issue where when we try to dump the trace, we pass only the unread portion of the bytes.Buffer. Change-Id: I1a338eea08eaf7f592fb7dd2a736a6fe0728c62d Reviewed-on: https://go-review.googlesource.com/c/go/+/729320 Reviewed-by: Carlos Amedee <carlos@golang.org> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2025-12-08runtime/trace: update TestSubscribers to dump tracesMichael Anthony Knyszek
CL 710755 missed this test suite. For #75665. Change-Id: Id2f1ab2eae2c20ea5056e893951a73c0b851f0eb Reviewed-on: https://go-review.googlesource.com/c/go/+/728200 Reviewed-by: Michael Pratt <mpratt@google.com> Auto-Submit: Michael Knyszek <mknyszek@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2025-11-21runtime/trace: add Log benchmarkMichael Anthony Knyszek
This is a pretty decent benchmark of the baseline event cost. Change-Id: I22a7fa3411bd80be3bd8093d5933e29062cb1377 Reviewed-on: https://go-review.googlesource.com/c/go/+/723060 Reviewed-by: Michael Pratt <mpratt@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2025-10-20runtime/trace: dump test traces on validation failureMichael Anthony Knyszek
We currently dump traces for internal/trace tests on validation failure, but not for the runtime/trace package. This change moves some of the machinery to do this into the testtrace package and then uses it from the runtime/trace package. For #75665. Change-Id: Ibe2d4f3945c1fd21dcbccf56820865f8d2ea41f9 Reviewed-on: https://go-review.googlesource.com/c/go/+/710755 Reviewed-by: Michael Pratt <mpratt@google.com> Auto-Submit: Michael Knyszek <mknyszek@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2025-08-15internal/trace: add end-of-generation signal to traceMichael Anthony Knyszek
This change takes the EvEndOfGeneration event and promotes it to a real event that appears in the trace. This allows the trace parser to unambiguously identify truncated traces vs. broken traces. It also makes a lot of the logic around parsing simpler, because there's no more batch spilling necessary. Fixes #73904. Change-Id: I37c359b32b6b5f894825aafc02921adeaacf2595 Reviewed-on: https://go-review.googlesource.com/c/go/+/693398 Reviewed-by: Carlos Amedee <carlos@golang.org> Reviewed-by: Michael Pratt <mpratt@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2025-08-13runtime/trace: fix documentation typoAlexey Palazhchenko
Change-Id: I3d8dc20536c7a1fb4b1d895fcf989f86bf45f499 GitHub-Last-Rev: 234aea60e25b01e84abdf485cebbd0da5f392fed GitHub-Pull-Request: golang/go#74991 Reviewed-on: https://go-review.googlesource.com/c/go/+/695535 LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Michael Knyszek <mknyszek@google.com> Reviewed-by: qiu laidongfeng <2645477756@qq.com> Auto-Submit: Michael Knyszek <mknyszek@google.com> Reviewed-by: David Chase <drchase@google.com>
2025-05-27runtime/trace: add a trace validation test for different trace ordersCarlos Amedee
This adds a test which validates the traces generated by the execution tracer and the flight recorder depending on the order where they are stopped and started. This test uncovered that under certain circumstances, the traces which were produced would possibly be missing the trace header. All traces have the trace headers included now. Clock snapshot checks have been disabled for Windows and WASM. Change-Id: I5be719d228300469891fc56817fbce4ba5453fff Reviewed-on: https://go-review.googlesource.com/c/go/+/675975 Auto-Submit: Carlos Amedee <carlos@golang.org> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Michael Knyszek <mknyszek@google.com>
2025-05-23runtime/trace: match traceClockNow typesMichael Pratt
runtime.traceClockNow returns a (named) uint64. Make the declaration in runtime/trace match this type. Change-Id: I6a6a636ce3596cbc6fc5bac3590703b7b4839c4d Reviewed-on: https://go-review.googlesource.com/c/go/+/675976 Reviewed-by: Carlos Amedee <carlos@golang.org> Auto-Submit: Michael Pratt <mpratt@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2025-05-23runtime/trace: fix flaky test for SetMinAgeCarlos Amedee
This change fixes the flaky test which expects setting SetMinAge to a small ammount. It expects two sync events but should realistically expect up to 3. Change-Id: Ibd02fe55ebca99eb880025eb968fcebae9cb09c9 Reviewed-on: https://go-review.googlesource.com/c/go/+/675597 Reviewed-by: Michael Knyszek <mknyszek@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2025-05-21runtime/trace: add the flight recorderCarlos Amedee
This change adds the flight recorder to the trace package. Flight recording is a technique in which trace data is kept in a circular buffer and can be flushed upon request. The implementation will be added in follow-up CLs. The flight recorder has already been implemented inside of the golang.org/x/exp/trace package. This copies the current implementation and modifies it to work within the runtime/trace package. The changes include: This adds the ability for multiple consumers (both the execution tracer and the flight recorder) to subscribe to tracing events. This change allows us to add multiple consumers without making major modifications to the runtime. Future optimizations are planned for this functionality. This removes the use of byte readers from the process that parses and processes the trace batches. This modifies the flight recorder to not parse out the trace clock frequency, since that requires knowledge of the format that's unfortunate to encode in yet another place. Right now, the trace clock frequency is considered stable for the lifetime of the program, so just grab it directly from the runtime. This change adds an in-band end-of-generation signal to the internal implementation of runtime.ReadTrace. The internal implementation is exported via linkname to runtime/trace, so the flight recorder can identify exactly when a generation has ended. This signal is also useful for ensuring that subscribers to runtime trace data always see complete generations, by starting or stopping data streaming only at generation boundaries. For #63185 Change-Id: I5c15345981a6bbe9764a3d623448237e983c64ec Reviewed-on: https://go-review.googlesource.com/c/go/+/673116 Auto-Submit: Michael Knyszek <mknyszek@google.com> Reviewed-by: Michael Knyszek <mknyszek@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2024-04-15runtime, cmd/trace: remove code paths that include v1 tracerCarlos Amedee
This change makes the new execution tracer described in #60773, the default tracer. This change attempts to make the smallest amount of changes for a single CL. Updates #66703 For #60773 Change-Id: I3742f3419c54f07d7c020ae5e1c18d29d8bcae6d Reviewed-on: https://go-review.googlesource.com/c/go/+/576256 Reviewed-by: Michael Knyszek <mknyszek@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2023-11-10runtime: add execution tracer v2 behind GOEXPERIMENT=exectracer2Michael Anthony Knyszek
This change mostly implements the design described in #60773 and includes a new scalable parser for the new trace format, available in internal/trace/v2. I'll leave this commit message short because this is clearly an enormous CL with a lot of detail. This change does not hook up the new tracer into cmd/trace yet. A follow-up CL will handle that. For #60773. Cq-Include-Trybots: luci.golang.try:gotip-linux-amd64-longtest,gotip-linux-amd64-longtest-race Change-Id: I5d2aca2cc07580ed3c76a9813ac48ec96b157de0 Reviewed-on: https://go-review.googlesource.com/c/go/+/494187 Reviewed-by: Michael Pratt <mpratt@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2023-06-20runtime/trace: add godoc linksOlivier Mengué
Change-Id: I6db8ce8d7e0a1cb3d955493fa49eb7dff372eb38 Reviewed-on: https://go-review.googlesource.com/c/go/+/504375 Run-TryBot: Ian Lance Taylor <iant@google.com> Reviewed-by: Ian Lance Taylor <iant@google.com> Auto-Submit: Ian Lance Taylor <iant@google.com> Reviewed-by: Dmitri Shuralyov <dmitshur@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
2023-04-06runtime: add remaining wasip1 filesJohan Brandhorst-Satzkorn
Implements OS interactions and memory management. For #58141 Co-authored-by: Richard Musiol <neelance@gmail.com> Co-authored-by: Achille Roussel <achille.roussel@gmail.com> Co-authored-by: Julien Fabre <ju.pryz@gmail.com> Co-authored-by: Evan Phoenix <evan@phx.io> Change-Id: I876e7b033090c2fe2d76d2535bb63d52efa36185 Reviewed-on: https://go-review.googlesource.com/c/go/+/479618 TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Cherry Mui <cherryyz@google.com> Reviewed-by: Ian Lance Taylor <iant@google.com> Run-TryBot: Cherry Mui <cherryyz@google.com> Auto-Submit: Ian Lance Taylor <iant@golang.org> Run-TryBot: Ian Lance Taylor <iant@golang.org>
2023-03-09runtime/trace: update outdated Task and Region documentationNick Ripley
A previous iteration of the tracer's user annotation API had different names for tasks and regions, and used to return functions for ending them rather than types with End methods. This CL updates the doc comments to reflect those changes, and also fixes up the internal documentation of the events (similar to go.dev/cl/465335, the stack argument was in the wrong place in the list). The User Log event internal documentation might also look wrong since the value argument follows the stack argument. However, the User Log event is a special case where the log message is appended immediately following the normal event, including the stack argument. There isn't much room to clarify this next to the event type definitions, so this CL clarifies the comment where the event is encoded. Change-Id: I846c709f6026ef01c0a272557d6390b2c17074e0 Reviewed-on: https://go-review.googlesource.com/c/go/+/472955 Reviewed-by: Michael Pratt <mpratt@google.com> Reviewed-by: Carlos Amedee <carlos@golang.org> Auto-Submit: Michael Pratt <mpratt@google.com> Run-TryBot: Michael Pratt <mpratt@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Run-TryBot: Nick Ripley <nick.ripley@datadoghq.com>
2023-02-08runtime: correct typosOleksandr Redko
- Fix typo in throw error message for arena. - Correct typos in assembly and Go comments. - Fix log message in TestTraceCPUProfile. Change-Id: I874c9e8cd46394448b6717bc6021aa3ecf319d16 GitHub-Last-Rev: d27fad4d3cea81cc7a4ca6917985bcf5fa49b0e0 GitHub-Pull-Request: golang/go#58375 Reviewed-on: https://go-review.googlesource.com/c/go/+/465975 Reviewed-by: David Chase <drchase@google.com> Reviewed-by: Ian Lance Taylor <iant@google.com> Run-TryBot: Ian Lance Taylor <iant@google.com> Auto-Submit: Ian Lance Taylor <iant@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
2022-09-14all: remove unnecessary allocations from w.WriteString(fmt.Sprint*(...)) by ↵Emmanuel T Odeke
fmt.Fprint*(w, ...) Noticed in a manual audit from a customer codebase that the pattern w.WriteString(fmt.Sprint*(args...)) was less efficient and in most cases we can just invoke: fmt.Fprint*(w, args...) and from the simple benchmarks we can see quick wins in all dimensions: $ benchstat before.txt after.txt name old time/op new time/op delta DetailString-8 5.48µs ±23% 4.40µs ±11% -19.79% (p=0.000 n=20+17) name old alloc/op new alloc/op delta DetailString-8 2.63kB ± 0% 2.11kB ± 0% -19.76% (p=0.000 n=20+20) name old allocs/op new allocs/op delta DetailString-8 63.0 ± 0% 50.0 ± 0% -20.63% (p=0.000 n=20+20) Change-Id: I47a2827cd34d6b92644900b1bd5f4c0a3287bdb1 Reviewed-on: https://go-review.googlesource.com/c/go/+/429861 Reviewed-by: Robert Findley <rfindley@google.com> Reviewed-by: hopehook <hopehook@golangcn.org> Reviewed-by: Ian Lance Taylor <iant@google.com> Run-TryBot: Emmanuel Odeke <emmanuel@orijtech.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
2022-08-17runtime/trace: convert tracing.enabled to atomic typeCuong Manh Le
Updates #53821 Change-Id: I8a063ae94568cd2ea65c2e891618069a96139891 Reviewed-on: https://go-review.googlesource.com/c/go/+/423884 Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Michael Pratt <mpratt@google.com> Reviewed-by: Keith Randall <khr@google.com> Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>
2022-06-21runtime/trace: ignore fallback stacks in testRhys Hiltner
When runtime.sigprof encounters a stack that gentraceback is unable to process, it synthesizes a call stack with a sentinel function (such as runtime._System) at the leaf. The test to confirm that runtime/trace and runtime/pprof have similar views of CPU profile samples has trouble with those stacks. The test confirms that the samples match by confirming that their symbolized forms match, and the symbolization procedure is very different for the two packages. Skip the samples that the CPU profiler's view symbolizes to include one of runtime.sigprof's sentinel functions at the leaf. (The test design expects the CPU profiler to under-report samples relative to the execution tracer.) Fixes #53378 Change-Id: I60c27de4c69b454057d28a3b6e12d70369de4c4f Reviewed-on: https://go-review.googlesource.com/c/go/+/413457 Reviewed-by: Bryan Mills <bcmills@google.com> Run-TryBot: Rhys Hiltner <rhys@justin.tv> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Michael Pratt <mpratt@google.com>
2022-05-05runtime: prefer curg for execution trace profileRhys Hiltner
The CPU profiler adds goroutine labels to its samples based on getg().m.curg. That allows the profile to correctly attribute work that the runtime does on behalf of that goroutine on the M's g0 stack via systemstack calls, such as using runtime.Callers to record the call stack. Those labels also cover work on the g0 stack via mcall. When the active goroutine calls runtime.Gosched, it will receive attribution of its share of the scheduler work necessary to find the next runnable goroutine. The execution tracer's attribution of CPU samples to specific goroutines should match. When curg is set, attribute the CPU samples to that goroutine's ID. Fixes #52693 Change-Id: Ic9af92e153abd8477559e48bc8ebaf3739527b94 Reviewed-on: https://go-review.googlesource.com/c/go/+/404055 Reviewed-by: Michael Knyszek <mknyszek@google.com> Reviewed-by: Bryan Mills <bcmills@google.com> Run-TryBot: Rhys Hiltner <rhys@justin.tv> TryBot-Result: Gopher Robot <gobot@golang.org>
2022-05-03runtime: add CPU samples to execution traceRhys Hiltner
When the CPU profiler and execution tracer are both active, report the CPU profile samples in the execution trace data stream. Include only samples that arrive on the threads known to the runtime, but include them even when running g0 (such as near the scheduler) or if there's no P (such as near syscalls). Render them in "go tool trace" as instantaneous events. For #16895 Change-Id: I0aa501a7b450c971e510961c0290838729033f7f Reviewed-on: https://go-review.googlesource.com/c/go/+/400795 Reviewed-by: Michael Knyszek <mknyszek@google.com> Run-TryBot: Rhys Hiltner <rhys@justin.tv> Reviewed-by: David Chase <drchase@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
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>
2022-04-01all: remove trailing blank doc comment linesRuss Cox
A future change to gofmt will rewrite // Doc comment. // func f() to // Doc comment. func f() Apply that change preemptively to all doc comments. For #51082. Change-Id: I4023e16cfb0729b64a8590f071cd92f17343081d Reviewed-on: https://go-review.googlesource.com/c/go/+/384259 Trust: Russ Cox <rsc@golang.org> Run-TryBot: Russ Cox <rsc@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gopher Robot <gobot@golang.org>
2021-12-13all: gofmt -w -r 'interface{} -> any' srcRuss Cox
And then revert the bootstrap cmd directories and certain testdata. And adjust tests as needed. Not reverting the changes in std that are bootstrapped, because some of those changes would appear in API docs, and we want to use any consistently. Instead, rewrite 'any' to 'interface{}' in cmd/dist for those directories when preparing the bootstrap copy. A few files changed as a result of running gofmt -w not because of interface{} -> any but because they hadn't been updated for the new //go:build lines. Fixes #49884. Change-Id: Ie8045cba995f65bd79c694ec77a1b3d1fe01bb09 Reviewed-on: https://go-review.googlesource.com/c/go/+/368254 Trust: Russ Cox <rsc@golang.org> Run-TryBot: Russ Cox <rsc@golang.org> Reviewed-by: Robert Griesemer <gri@golang.org> TryBot-Result: Gopher Robot <gobot@golang.org>
2020-12-09all: update to use os.ReadFile, os.WriteFile, os.CreateTemp, os.MkdirTempRuss Cox
As part of #42026, these helpers from io/ioutil were moved to os. (ioutil.TempFile and TempDir became os.CreateTemp and MkdirTemp.) Update the Go tree to use the preferred names. As usual, code compiled with the Go 1.4 bootstrap toolchain and code vendored from other sources is excluded. ReadDir changes are in a separate CL, because they are not a simple search and replace. For #42026. Change-Id: If318df0216d57e95ea0c4093b89f65e5b0ababb3 Reviewed-on: https://go-review.googlesource.com/c/go/+/266365 Trust: Russ Cox <rsc@golang.org> Run-TryBot: Russ Cox <rsc@golang.org> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2020-09-02runtime: add file copyright header declarationHeisenberg
Some files have no copyright notice. The copyright time is the earliest modification record of the file. Change-Id: I5698bae16b6b73543e074415877a03348f792951 Reviewed-on: https://go-review.googlesource.com/c/go/+/246378 Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
2020-08-19os, internal/poll: loop on EINTR for all file syscallsIan Lance Taylor
When using a FUSE file system, any system call that touches the file system can return EINTR. Fixes #40846 Change-Id: I25d32da22cec08dea81ab297291a85ad72db2df7 Reviewed-on: https://go-review.googlesource.com/c/go/+/249178 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Bryan C. Mills <bcmills@google.com>
2020-06-19runtime/trace: fix file name in exampleRodolfo Carvalho
The preceding paragraph suggests the test run will produce a file called trace.out. The same name, trace.out, is used in the output from go help testflag, thus we change the go test line instead of changing the preceding paragraph. Change-Id: Ib1fa7e49e540853e263a2399b16040ea6f41b703 GitHub-Last-Rev: 3535e62bf8dd02dd9955a28e7fa9cca98de89efd GitHub-Pull-Request: golang/go#39709 Reviewed-on: https://go-review.googlesource.com/c/go/+/238997 Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
2020-05-11internal/poll, os: loop on EINTRIan Lance Taylor
Historically we've assumed that we can install all signal handlers with the SA_RESTART flag set, and let the system restart slow functions if a signal is received. Therefore, we don't have to worry about EINTR. This is only partially true, and we've added EINTR checks already for connect, and open/read on Darwin, and sendfile on Solaris. Other cases have turned up in #36644, #38033, and #38836. Also, #20400 points out that when Go code is included in a C program, the C program may install its own signal handlers without SA_RESTART. In that case, Go code will see EINTR no matter what it does. So, go ahead and check for EINTR. We don't check in the syscall package; people using syscalls directly may want to check for EINTR themselves. But we do check for EINTR in the higher level APIs in os and net, and retry the system call if we see it. This change looks safe, but of course we may be missing some cases where we need to check for EINTR. As such cases turn up, we can add tests to runtime/testdata/testprogcgo/eintr.go, and fix the code. If there are any such cases, their handling after this change will be no worse than it is today. For #22838 Fixes #20400 Fixes #36644 Fixes #38033 Fixes #38836 Change-Id: I7e46ca8cafed0429c7a2386cc9edc9d9d47a6896 Reviewed-on: https://go-review.googlesource.com/c/go/+/232862 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Bryan C. Mills <bcmills@google.com>
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>
2019-05-22all: shorten some testsRuss Cox
Shorten some of the longest tests that run during all.bash. Removes 7r 50u 21s from all.bash. After this change, all.bash is under 5 minutes again on my laptop. For #26473. Change-Id: Ie0460aa935808d65460408feaed210fbaa1d5d79 Reviewed-on: https://go-review.googlesource.com/c/go/+/177559 Run-TryBot: Russ Cox <rsc@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2019-04-18runtime/trace: also treat plan9 as a low memory systemBrad Fitzpatrick
Fixes #31554 Updates #12032 (also originally about plan9, but later openbsd/arm) Change-Id: Ib9f35d27a2304f38bf271c38c0b9153d210d8f95 Reviewed-on: https://go-review.googlesource.com/c/go/+/172837 Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> Reviewed-by: David du Colombier <0intro@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org>
2018-12-02all: use "reports whether" consistently instead of "returns whether"Tobias Klauser
Follow-up for CL 147037 and after Brad noticed the "returns whether" pattern during the review of CL 150621. Go documentation style for boolean funcs is to say: // Foo reports whether ... func Foo() bool (rather than "returns whether") Created with: $ perl -i -npe 's/returns whether/reports whether/' $(git grep -l "returns whether" | grep -v vendor) Change-Id: I15fe9ff99180ad97750cd05a10eceafdb12dc0b4 Reviewed-on: https://go-review.googlesource.com/c/150918 Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-09-03runtime/trace: fix syntax errors in NewTask doc exampleCharles Kenney
Fixes #27406 Change-Id: I9c6f5bac5b26558fa7628233c74a62faf676e811 GitHub-Last-Rev: 29d19f719316b486224a15a50556465811985edf GitHub-Pull-Request: golang/go#27437 Reviewed-on: https://go-review.googlesource.com/132775 Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com> Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org>
2018-07-10runtime/trace: comment newlines to restore correct doc summaryAlberto Donizetti
Fixes #26309 Change-Id: I0e0b61b885817e514aa46e299b00833f16e98b2a Reviewed-on: https://go-review.googlesource.com/122898 Reviewed-by: Айнар Гарипов <gugl.zadolbal@gmail.com> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-06-25runtime/trace: reword the trace package summaryJeremy Jackins
Reword the package summary to be a little easier to read. Change-Id: I84a9301a02e228b46165410a429548b3774762d5 GitHub-Last-Rev: 1342c7219f0ed06144d3bca9acd77790707e4b77 GitHub-Pull-Request: golang/go#26052 Reviewed-on: https://go-review.googlesource.com/120795 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-06-01runtime/trace: remove remaining NewContext referenceHana Kim
This is a documentation error. Change-Id: I083021f151f7e80a0b9083b98452ae1f5920640d Reviewed-on: https://go-review.googlesource.com/115598 Reviewed-by: Peter Weinberger <pjw@google.com>
2018-06-01os: add js/wasm architectureRichard Musiol
This commit adds the js/wasm architecture to the os package. Access to the actual file system is supported through Node.js. Updates #18892 Change-Id: I6fa642fb294ca020b2c545649d4324d981aa0408 Reviewed-on: https://go-review.googlesource.com/109977 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org> Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
2018-05-09runtime/trace: delete functions replaced by cl/108296Hana Kim
Change-Id: I9bd4e13aafce14f76606b0f96496f621232c9e37 Reviewed-on: https://go-review.googlesource.com/112198 Reviewed-by: Peter Weinberger <pjw@google.com> Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org>
2018-04-24runtime/trace: add simple benchmarks for user annotationHana Kim
Also, avoid Region creation when tracing is disabled. Unfortunate side-effect of this change is that we no longer trace pre-existing regions in tracing, but we can add the feature in the future when we find it useful and justifiable. Until then, let's avoid the overhead from this low-level api use as much as possible. goos: linux goarch: amd64 pkg: runtime/trace // Trace disabled BenchmarkStartRegion-12 2000000000 0.66 ns/op 0 B/op 0 allocs/op BenchmarkNewTask-12 30000000 40.4 ns/op 56 B/op 2 allocs/op // Trace enabled, -trace=/dev/null BenchmarkStartRegion-12 5000000 287 ns/op 32 B/op 1 allocs/op BenchmarkNewTask-12 5000000 283 ns/op 56 B/op 2 allocs/op Also, skip other tests if tracing is already enabled. Change-Id: Id3028d60b5642fcab4b09a74fd7d79361a3861e5 Reviewed-on: https://go-review.googlesource.com/109115 Reviewed-by: Peter Weinberger <pjw@google.com>
2018-04-24runtime/trace: rename "Span" with "Region"Hana Kim
"Span" is a commonly used term in many distributed tracing systems (Dapper, OpenCensus, OpenTracing, ...). They use it to refer to a period of time, not necessarily tied into execution of underlying processor, thread, or goroutine, unlike the "Span" of runtime/trace package. Since distributed tracing and go runtime execution tracing are already similar enough to cause confusion, this CL attempts to avoid using the same word if possible. "Region" is being used in a certain tracing system to refer to a code region which is pretty close to what runtime/trace.Span currently refers to. So, replace that. https://software.intel.com/en-us/itc-user-and-reference-guide-defining-and-recording-functions-or-regions This CL also tweaks APIs a bit based on jbd and heschi's comments: NewContext -> NewTask and it now returns a Task object that exports End method. StartSpan -> StartRegion and it now returns a Region object that exports End method. Also, changed WithSpan to WithRegion and it now takes func() with no context. Another thought is to get rid of WithRegion. It is a nice concept but in practice, it seems problematic (a lot of code churn, and polluting stack trace). Already, the tracing concept is very low level, and we hope this API to be used with great care. Recommended usage will be defer trace.StartRegion(ctx, "someRegion").End() Left old APIs untouched in this CL. Once the usage of them are cleaned up, they will be removed in a separate CL. Change-Id: I73880635e437f3aad51314331a035dd1459b9f3a Reviewed-on: https://go-review.googlesource.com/108296 Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: JBD <jbd@google.com>
2018-03-05internal/trace: remove backlinks from span/task end to startHana Kim
This is an updated version of golang.org/cl/96395, with the fix to TestUserSpan. This reverts commit 7b6f6267e90a8e4eab37a3f2164ba882e6222adb. Change-Id: I31eec8ba0997f9178dffef8dac608e731ab70872 Reviewed-on: https://go-review.googlesource.com/98236 Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Heschi Kreinick <heschi@google.com>
2018-03-01runtime/trace: skip TestUserTaskSpan upon timestamp errorHana Kim
Change-Id: I030baaa0a0abf1e43449faaf676d389a28a868a3 Reviewed-on: https://go-review.googlesource.com/97857 Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com> Reviewed-by: Peter Weinberger <pjw@google.com>
2018-02-18all: remove "the" duplicationsKunpei Sakai
Change-Id: I1f25b11fb9b7cd3c09968ed99913dc85db2025ef Reviewed-on: https://go-review.googlesource.com/94976 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-02-15internal/trace: link user span start and end eventsHana Kim
Also add testdata for version 1.11 including UserTaskSpan test trace. Change-Id: I673fb29bb3aee96a14fadc0ab860d4f5832143f5 Reviewed-on: https://go-review.googlesource.com/93795 Reviewed-by: Heschi Kreinick <heschi@google.com>
generated by cgit v1.3 (git 2.53.0) at 2026-04-16 20:11:06 +0000