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24 hoursall: prealloc slice with possible minimum capabilitiesShulhan
2026-03-30internal/trace/tracev2: add String for ProcSyscallAbandonedFlorian Lehner
Add missing string for ProcSyscallAbandoned. Change-Id: Ie6b049001432c2b667716d4eff95783c7eb1f350 Reviewed-on: https://go-review.googlesource.com/c/go/+/760840 Reviewed-by: Michael Knyszek <mknyszek@google.com> Auto-Submit: Michael Pratt <mpratt@google.com> TryBot-Bypass: Michael Pratt <mpratt@google.com> Reviewed-by: Michael Pratt <mpratt@google.com>
2026-03-26internal/trace: preallocate pcs array to correct sizeFlorian Lehner
Avoid additional allocations by requesting the correct size of the array. Change-Id: Ib1bcabdfc978c4dabf139c37e45d436182dec2d2 Reviewed-on: https://go-review.googlesource.com/c/go/+/757800 Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Dmitri Shuralyov <dmitshur@google.com> Reviewed-by: Michael Knyszek <mknyszek@google.com>
2025-12-11internal/trace: correctly handle GoUndetermined for GoroutineSummaryMichael Anthony Knyszek
Currently the trace summarization incorrectly handles GoUndetermined by treating it too much like GoNotExist. In particular, it should be accumulating all the time since the start of the trace in a particular bucket, but it doesn't, so that instead gets counted as "unknown time" because the "creation time" is at the start of the trace. This change fixes the problem by simply doing the accumulation. It's very straightforward. It also side-steps some other inaccuracies, like associating a goroutine that is being named with the current task. I don't think this can ever actually happen in practice, but splitting up the two cases, GoUndetermined and GoNotExist, fixes it. Fixes #76716. Change-Id: I3ac1557044f99c92bada2cb0e124b2192b1d6ebb Reviewed-on: https://go-review.googlesource.com/c/go/+/728822 LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Carlos Amedee <carlos@golang.org> Reviewed-by: Nick Ripley <nick.ripley@datadoghq.com>
2025-12-08internal/trace: skip tests for alloc/free experiment by defaultMichael Anthony Knyszek
These tests are just too flaky and I don't have the time to fix them right now. I also am thinking to just change how trace experiments work, so it may not be worth taking the time to fix them. For #70838. Change-Id: Ia896215a0cbeccac99b73fefc836088f43530849 Reviewed-on: https://go-review.googlesource.com/c/go/+/728122 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>
2025-11-26internal/trace: support event constructor for testingFelix Geisendörfer
Implement the new APIs described in #74826. Closes #74826 Change-Id: I6a6a6964229548e9d54e7af95185011e183ee50b Reviewed-on: https://go-review.googlesource.com/c/go/+/691815 Reviewed-by: Michael Knyszek <mknyszek@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2025-11-21internal/trace: go fmtMichael Pratt
Change-Id: I6a6a636c8f14008d3da6c526be10fa3386d4ec32 Reviewed-on: https://go-review.googlesource.com/c/go/+/722522 Auto-Submit: Michael Pratt <mpratt@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Michael Knyszek <mknyszek@google.com>
2025-11-13cmd/trace: annotation proc start/stop with thread and proc alwaysMichael Anthony Knyszek
In the proc view, the thread ID is useful. In the thread view, the proc ID is useful. Add both in both cases forever more. Change-Id: I9cb7bd67a21ee17d865c25d73b2049b3da7aefbc Reviewed-on: https://go-review.googlesource.com/c/go/+/720402 LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Michael Pratt <mpratt@google.com> Auto-Submit: Michael Knyszek <mknyszek@google.com>
2025-11-13runtime: prefer to restart Ps on the same M after STWMichael Pratt
Today, Ps jump around arbitrarily across STW. Instead, try to keep the P on the previous M it ran on. In the future, we'll likely want to try to expand this beyond STW to create a more general affinity for specific Ms. For this to be useful, the Ps need to have runnable Gs. Today, STW preemption goes through goschedImpl, which places the G on the global run queue. If that was the only G then the P won't have runnable goroutines anymore. It makes more sense to keep the G with its P across STW anyway, so add a special case to goschedImpl for that. On my machine, this CL reduces the error rate in TestTraceSTW from 99.8% to 1.9%. As a nearly 2% error rate shows, there are still cases where this best effort scheduling doesn't work. The most obvious is that while procresize assigns Ps back to their original M, startTheWorldWithSema calls wakep to start a spinning M. The spinning M may steal a goroutine from another P if that P is too slow to start. For #65694. Change-Id: I6a6a636c0969c587d039b68bc68ea16c74ff1fc9 Reviewed-on: https://go-review.googlesource.com/c/go/+/714801 Reviewed-by: Michael Knyszek <mknyszek@google.com> Auto-Submit: Michael Pratt <mpratt@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2025-11-11internal/trace/testtrace: fix flag name typosMichael Pratt
Change-Id: I6a6a636cd82a3e22a482ea2b2ab1004c45e2c304 Reviewed-on: https://go-review.googlesource.com/c/go/+/719400 Auto-Submit: Michael Pratt <mpratt@google.com> Reviewed-by: Michael Knyszek <mknyszek@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2025-11-10internal/trace: add "command" to convert text traces to rawMichael Pratt
This is primarily helpful for parsing traces dumped via CI. cmd/dist doesn't like commands in std which are not actually part of the Go distribution. So rather than using a real command, this is actually a test which does the conversion. Change-Id: I6a6a636c829a4acc0bce8cf7548105ad59d83c67 Reviewed-on: https://go-review.googlesource.com/c/go/+/716882 Reviewed-by: Michael Knyszek <mknyszek@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2025-10-21runtime,syscall: implement and use syscalln on darwinqmuntal
All darwin syscall implementations can be consolidated into a single syscalln function, as already happens on Windows. This reduces duplication and allows moving some logic from runtime to syscall. Updates #699135 Cq-Include-Trybots: luci.golang.try:gotip-darwin-arm64-longtest,gotip-darwin-amd64-longtest,x_sys-gotip-darwin-arm64-longtest,x_sys-gotip-darwin-amd64-longtest Change-Id: If5de80442b1d4a1123258401a3ae21695e7c8f6b Reviewed-on: https://go-review.googlesource.com/c/go/+/699177 LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: David Chase <drchase@google.com> Reviewed-by: Michael Pratt <mpratt@google.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>
2025-10-17all: remove unnecessary loop variable copies in testsTobias Klauser
Copying the loop variable is no longer necessary since Go 1.22. Change-Id: Iebb21dac44a20ec200567f1d786f105a4ee4999d Reviewed-on: https://go-review.googlesource.com/c/go/+/711640 Reviewed-by: Florian Lehner <lehner.florian86@gmail.com> Auto-Submit: Damien Neil <dneil@google.com> Reviewed-by: Dmitri Shuralyov <dmitshur@google.com> Reviewed-by: Damien Neil <dneil@google.com> Auto-Submit: Tobias Klauser <tobias.klauser@gmail.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2025-10-17all: correct name for commentsJes Cok
Change-Id: I390c380349e99ad421264b673ad7734eddb639d3 GitHub-Last-Rev: 32e849a6420574b0d878b9a449a8c044fd6ebdd1 GitHub-Pull-Request: golang/go#75905 Reviewed-on: https://go-review.googlesource.com/c/go/+/711941 Reviewed-by: Jorropo <jorropo.pgm@gmail.com> Reviewed-by: Keith Randall <khr@golang.org> Reviewed-by: Keith Randall <khr@google.com> Auto-Submit: Jorropo <jorropo.pgm@gmail.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Auto-Submit: Keith Randall <khr@golang.org> Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
2025-09-15all: replace strings.Split with strings.SplitSeq1911860538
In Go 1.25+, strings.SplitSeq offers better performance. Here are the benchmark results comparing strings.Split and strings.SplitSeq in a for-loop, with the benchmark code located in src/strings/iter_test.go: goos: darwin goarch: amd64 pkg: cmd/go/internal/auth cpu: Intel(R) Core(TM) i7-8569U CPU @ 2.80GHz │ old.txt │ new.txt │ │ sec/op │ sec/op vs base │ ParseGitAuth/standard-8 281.4n ± 1% 218.0n ± 11% -22.54% (p=0.000 n=10) ParseGitAuth/with_url-8 549.1n ± 1% 480.5n ± 13% -12.48% (p=0.002 n=10) ParseGitAuth/minimal-8 235.4n ± 1% 197.3n ± 7% -16.20% (p=0.000 n=10) ParseGitAuth/complex-8 797.6n ± 2% 805.2n ± 4% ~ (p=0.481 n=10) ParseGitAuth/empty-8 87.48n ± 3% 63.25n ± 6% -27.71% (p=0.000 n=10) ParseGitAuth/malformed-8 228.8n ± 1% 171.2n ± 3% -25.17% (p=0.000 n=10) geomean 288.9n 237.7n -17.72% │ old.txt │ new.txt │ │ B/op │ B/op vs base │ ParseGitAuth/standard-8 192.00 ± 0% 96.00 ± 0% -50.00% (p=0.000 n=10) ParseGitAuth/with_url-8 400.0 ± 0% 288.0 ± 0% -28.00% (p=0.000 n=10) ParseGitAuth/minimal-8 144.00 ± 0% 80.00 ± 0% -44.44% (p=0.000 n=10) ParseGitAuth/complex-8 528.0 ± 0% 400.0 ± 0% -24.24% (p=0.000 n=10) ParseGitAuth/empty-8 32.00 ± 0% 16.00 ± 0% -50.00% (p=0.000 n=10) ParseGitAuth/malformed-8 176.00 ± 0% 80.00 ± 0% -54.55% (p=0.000 n=10) geomean 179.0 102.1 -42.96% │ old.txt │ new.txt │ │ allocs/op │ allocs/op vs base │ ParseGitAuth/standard-8 3.000 ± 0% 2.000 ± 0% -33.33% (p=0.000 n=10) ParseGitAuth/with_url-8 4.000 ± 0% 3.000 ± 0% -25.00% (p=0.000 n=10) ParseGitAuth/minimal-8 3.000 ± 0% 2.000 ± 0% -33.33% (p=0.000 n=10) ParseGitAuth/complex-8 4.000 ± 0% 3.000 ± 0% -25.00% (p=0.000 n=10) ParseGitAuth/empty-8 2.000 ± 0% 1.000 ± 0% -50.00% (p=0.000 n=10) ParseGitAuth/malformed-8 3.000 ± 0% 2.000 ± 0% -33.33% (p=0.000 n=10) geomean 3.086 2.040 -33.91% Updates #69315. Change-Id: Id0219edea45d9658d527b863162ebe917e7821d9 GitHub-Last-Rev: 392b315e122f2c9ef8703ca2dbce8f82ec198556 GitHub-Pull-Request: golang/go#75259 Reviewed-on: https://go-review.googlesource.com/c/go/+/701015 Reviewed-by: Keith Randall <khr@golang.org> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Michael Knyszek <mknyszek@google.com> Reviewed-by: Emmanuel Odeke <emmanuel@orijtech.com> Reviewed-by: Keith Randall <khr@google.com> Auto-Submit: Emmanuel Odeke <emmanuel@orijtech.com>
2025-09-10internal/trace/raw: use strings.Cut instead of strings.SplitN 21911860538
Replace strings.SplitN with strings.Cut for better performance and readability. Change-Id: Ia245db62d8c2d1686887cb455f492db15606b57a GitHub-Last-Rev: e00e164688f79d85d34fdf0d4ef126387ec6c0a0 GitHub-Pull-Request: golang/go#75257 Reviewed-on: https://go-review.googlesource.com/c/go/+/700915 Reviewed-by: Michael Knyszek <mknyszek@google.com> Auto-Submit: Michael Pratt <mpratt@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Michael Pratt <mpratt@google.com>
2025-09-04cmd/trace: don't filter events for profile by whether they have stackMichael Anthony Knyszek
Right now the profile-from-trace code blindly discards events that don't have a stack, but this means it can discard 'end' events for goroutine time ranges that don't have stacks, like when a goroutine exits a syscall. This means we drop stack samples we *do* have, because we correctly already only use the stack trace of the corresponding 'start' event for a time-range-of-interest anyway. This change means that some events will be tracked that have no stack in their start event, but that's fine. It won't end up in the profile anyway because the stack is empty! And the rest of the code appears to be robust to an empty stack already. Thank you to Rhys Hiltner for reporting this issue and for the reproducer, which I have worked into a test for this change. Fixes #74850. Change-Id: I943b97ecf6b82803e4a778a0f83a14473d32254e Reviewed-on: https://go-review.googlesource.com/c/go/+/694156 Reviewed-by: Rhys Hiltner <rhys.hiltner@gmail.com> Reviewed-by: Michael Pratt <mpratt@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Carlos Amedee <carlos@golang.org>
2025-08-25internal/trace: skip async preempt off tests on low end systemsJoel Sing
The OpenBSD armv7 port does not support SMP - on this platform the trace tests take ~300 seconds to run when async preempt is disabled, which then times out on the builder. Skip these tests when run in short mode on a single CPU system. Change-Id: I9a697d5ba2b20652f76dcc97bd178a4ee8f1a2a0 Reviewed-on: https://go-review.googlesource.com/c/go/+/698555 LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Auto-Submit: Joel Sing <joel@sing.id.au> Reviewed-by: Cherry Mui <cherryyz@google.com> Reviewed-by: Michael Knyszek <mknyszek@google.com>
2025-08-19internal/trace: remove redundant info from Event.StringFelix Geisendörfer
Remove redundant information from state transition events. They currently mention the proc and goroutine id that is transitioning twice. Also reorder the reason to appear after the from->to state transition information since it is a detail that is not available for all transition. Before example: M=6164541440 P=3 G=17 StateTransition Time=7169014471424 Resource=Goroutine(17) Reason="chan receive" GoID=17 Running->Waiting M=6166261760 P=3 G=10 StateTransition Time=7169908799040 Resource=Proc(4) Reason="" ProcID=4 Idle->Idle After example: M=6164541440 P=3 G=17 StateTransition Time=7169014471424 GoID=17 Running->Waiting Reason="chan receive" M=6166261760 P=3 G=10 StateTransition Time=7169908799040 ProcID=4 Idle->Idle Reason="" Change-Id: I6a6a696487ff2905f7c98dae7e887b998a2cb298 Reviewed-on: https://go-review.googlesource.com/c/go/+/697356 LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Auto-Submit: Michael Knyszek <mknyszek@google.com> Reviewed-by: Michael Knyszek <mknyszek@google.com> Reviewed-by: Carlos Amedee <carlos@golang.org>
2025-08-19internal/trace: use RFC3339Nano for wall clock snapshots in Event.StringFelix Geisendörfer
Improve the quality of life for people who use go tool trace -d=parsed to look at clock snapshot wall timestamps. Many use cases will benefit from seing the timestamp in sub-second resolution. Change-Id: I6a6a696403a2164db0c12789c764e22a5c519b1c Reviewed-on: https://go-review.googlesource.com/c/go/+/697355 LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Auto-Submit: Michael Knyszek <mknyszek@google.com> Reviewed-by: Carlos Amedee <carlos@golang.org> Reviewed-by: Michael Knyszek <mknyszek@google.com>
2025-08-15internal/trace: emit final sync event for generation in Go 1.26+Michael Anthony Knyszek
CL 693398 returned the error from reading a generation immediately, but this is wrong -- a Sync event must be emitted to indicate the end of the trace before reporting the error. This caused TestCrashWhileTracing to fail because that test has a high likelihood of producing a truncated trace, and it expects at least 2 Sync events. The truncated trace error would be reported before the second Sync event, which is incorrect. Fixes #75045. Change-Id: Ia71592c4ec56a544afc85cdb7b575e143f80e048 Cq-Include-Trybots: luci.golang.try:gotip-linux-amd64-longtest Reviewed-on: https://go-review.googlesource.com/c/go/+/696436 Reviewed-by: Carlos Amedee <carlos@golang.org> 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>
2025-08-13internal/trace: fix wrong scope for Event.Range or EvGCSweepActiveFelix Geisendörfer
Change-Id: I6a6a69643e804c75914e6eedd32463cb825ab69f Reviewed-on: https://go-review.googlesource.com/c/go/+/694695 Reviewed-by: Michael Knyszek <mknyszek@google.com> Reviewed-by: David Chase <drchase@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Auto-Submit: Michael Knyszek <mknyszek@google.com>
2025-08-12internal/trace: clarify which StateTransition events have stacksFelix Geisendörfer
Clarify that EvGoDestroy, EvGoSyscallEnd and EvGoSyscallEndBlocked do not have a stack trace by removing the code that tries to assign an empty stack. Change-Id: I6a6a696479ac7f753b3c6f6f48d8b9b67f6e3b95 Reviewed-on: https://go-review.googlesource.com/c/go/+/694621 Reviewed-by: Michael Knyszek <mknyszek@google.com> Reviewed-by: David Chase <drchase@google.com> Auto-Submit: Michael Knyszek <mknyszek@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2025-08-12internal/trace: fix Sync.ClockSnapshot commentFelix Geisendörfer
The old comment said "clocks take in close in time" which was probably due to rewording this a few times. Replace the comment with the one of the ClockSnapshot type as there doesn't seem to be a good reason for using a different wording here. Change-Id: I6a6a69648c8470c2f45f6f8e728f5dc8b121a82b Reviewed-on: https://go-review.googlesource.com/c/go/+/694620 Reviewed-by: Michael Knyszek <mknyszek@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: David Chase <drchase@google.com> Auto-Submit: Michael Knyszek <mknyszek@google.com>
2025-08-12internal/trace: remove unused StateTransition.id fieldFelix Geisendörfer
Change-Id: I6a6a69647e6d91f9fd937032d95cbaf5d737fd5d Reviewed-on: https://go-review.googlesource.com/c/go/+/694619 LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: David Chase <drchase@google.com> Reviewed-by: Michael Knyszek <mknyszek@google.com> Auto-Submit: Michael Knyszek <mknyszek@google.com>
2025-08-12internal/trace/tracev2: adjust comment for consistencyFelix Geisendörfer
Adjust the EvGoStatus comment to use the term M ID in favor of thread ID in order to be consistent with the documentation for the other events. Change-Id: Ie9f6d52df6eea809682a33aa2bc9922a57fe03db Reviewed-on: https://go-review.googlesource.com/c/go/+/694618 LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Auto-Submit: Michael Knyszek <mknyszek@google.com> Reviewed-by: David Chase <drchase@google.com> Reviewed-by: Michael Knyszek <mknyszek@google.com>
2025-08-12internal/trace/tracev2: fix EvSTWBegin comment to include stack IDFelix Geisendörfer
Change-Id: I6a6a69644fb9a6e765933384cdb17c63458be69a Reviewed-on: https://go-review.googlesource.com/c/go/+/694617 Auto-Submit: Michael Knyszek <mknyszek@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: David Chase <drchase@google.com> Reviewed-by: Michael Knyszek <mknyszek@google.com>
2025-08-12internal/trace/internal/testgen: fix missing stacks nframes argFelix Geisendörfer
Change-Id: I6a6a6964c9c1322bfe289394d5d3937d1f7097bb Reviewed-on: https://go-review.googlesource.com/c/go/+/694616 Reviewed-by: Michael Knyszek <mknyszek@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: David Chase <drchase@google.com> Auto-Submit: Michael Knyszek <mknyszek@google.com>
2025-07-29internal/goexperiment: delete RangeFunc goexperimentCherry Mui
It is now always enabeld. The GOEXPERIMENT doesn't control anything. Remove. Change-Id: I50eb09f4537f90ec28152eb59a5a689127843fce Reviewed-on: https://go-review.googlesource.com/c/go/+/684838 Reviewed-by: Michael Knyszek <mknyszek@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2025-07-07internal/trace: only test for sync preemption if async preemption is offMichael Anthony Knyszek
Currently, the test change made for the fix to #68090 is flaky. This is because the sync-point-only goroutine that we expect to be sync preempted might only ever get async preempted in some circumstances. This change adds a variant to all trace tests to run with asyncpreemptoff=1, and the stacks test, the flaky one, only actually checks for the sync-point in the trace when async preemption is disabled. Fixes #74417. Change-Id: Ib6341bbc26921574b8f0fff6dd521ce83f85499c Reviewed-on: https://go-review.googlesource.com/c/go/+/686055 LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Cherry Mui <cherryyz@google.com>
2025-06-27runtime: account for missing frame pointer in preambleMichael Anthony Knyszek
If a goroutine is synchronously preempted, then taking a frame-pointer-based stack trace at that preemption will skip PC of the caller of the function which called into morestack. This happens because the frame pointer is pushed to the stack after the preamble, leaving the stack in an odd state for frame pointer unwinding. Deal with this by marking a goroutine as synchronously preempted and using that signal to load the missing PC from the stack. On LR platforms this is available in gp.sched.lr. On non-LR platforms like x86, it's at gp.sched.sp, because there are no args, no locals, and no frame pointer pushed to the SP yet. For #68090. Change-Id: I73a1206d8b84eecb8a96dbe727195da30088f288 Reviewed-on: https://go-review.googlesource.com/c/go/+/684435 Reviewed-by: Cherry Mui <cherryyz@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Nick Ripley <nick.ripley@datadoghq.com>
2025-06-23internal/trace: improve gc-stress testMichael Anthony Knyszek
The gc-stress test is useful for trying to exercise GC-related trace events by producing a lot of them in many different situations. Unfortunately this test is flaky, because allocating in a loop can easily out-run the GC when it's trying to preempt the allocating goroutine. It's been a long standing problem that a program that allocates in a loop can outrun a GC. The problem isn't the GC persay, it's consistently correlated with a high STW time (likely a high 'stopping' time, not a 'stopped' time), suggesting that in the window of time when the garbage collector is trying to stop all goroutines, they continue to allocate. This should probably be fixed in general, but for now, let's focus on this flaky test. This CL changes the gc-stress test to (1) set a memory limit and (2) do more work in between allocations. (2) is really what makes things less flaky, but (2) unfortunately also means the GC is less exercised. That's where (1) comes in. By setting a low memory limit, we increase GC activity (in particular, assist activity). The memory limit also helps prevent the heap from totally blowing up due to the heap goal inflating from floating garbage, but it's not perfect. After this change, under stress2, this test exceeds a heap size of 500 MiB only 1 in 5000 runs on my 64-vCPU VM. Before this change, it got that big about 1/4th of the time. Fixes #74052. Change-Id: I49233c914c8b65b1d593d3953891fddda6685aec Reviewed-on: https://go-review.googlesource.com/c/go/+/683515 Reviewed-by: Carlos Amedee <carlos@golang.org> Auto-Submit: Michael Knyszek <mknyszek@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2025-06-16internal/trace: make Value follow reflect conventionsMichael Anthony Knyszek
A previous change renamed Value.Uint64 to Value.ToUint64 to accomodate string values. The method for a string value is then Value.ToString, while the method for a debug string (for example, for fmt) is just called String, as per fmt.Stringer. This change follows a request from Dominik Honnef, maintainer of gotraceui, to make Value follow the conventions of the reflect package. The Value type there has a method String which fulfills both purposes: getting the string for a String Value, and as fmt.Stringer. It's not exactly pretty, but it does make sense to just stick to convention. Change-Id: I55b364be88088d2121527bffc833ef03dbdb9764 Reviewed-on: https://go-review.googlesource.com/c/go/+/680978 Reviewed-by: Florian Lehner <lehner.florian86@gmail.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Carlos Amedee <carlos@golang.org>
2025-06-12internal/trace: end test programs with SIGQUITMichael Anthony Knyszek
This change switches from using testenv.Command to testenv.CommandContext which is a little bit friendlier. It also switches away from using 'go run' to 'go build' and running the resulting binary explicitly. This helps eliminate any questions about signal handling and propagation. For #72740. Change-Id: Ife8010da89a7bc439e061fe0c9c6b1f5620d90f1 Reviewed-on: https://go-review.googlesource.com/c/go/+/680977 Reviewed-by: Carlos Amedee <carlos@golang.org> TryBot-Bypass: Michael Knyszek <mknyszek@google.com>
2025-06-10internal/trace: pass GOTRACEBACK=crash to testprogsMichael Anthony Knyszek
The failures in #70310 are hard to decipher. The cases where the lock is being held either don't really make sense (the STW failures) or the goroutine that fails is 'running on another thread' and we don't get a stack trace. In fact, such a goroutine exists even in the STW cases. Since reproducing this is going to be hard (very few failures over a 2 year span) let's set GOTRACEBACK=crash for these testprogs so next time it happens we can see why. For #70310. Change-Id: I81a780aa82b173d42973f06911cb243f33352be1 Reviewed-on: https://go-review.googlesource.com/c/go/+/680476 Reviewed-by: Michael Pratt <mpratt@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Carlos Amedee <carlos@golang.org>
2025-05-30internal/trace: expose the go version read by the readerCarlos Amedee
This change adds a function to expose the version set by the trace reader after reading the trace header (in tests). The trace validator needs to be able to determine what version of the trace it needs to validate against. Clock snapshot checks have been disabled for Windows and WASM. For #63185 Change-Id: Ia3d63e6ed7a5ecd87e63292b84cc417d982aaa5a Reviewed-on: https://go-review.googlesource.com/c/go/+/677695 LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Auto-Submit: Carlos Amedee <carlos@golang.org> Reviewed-by: Michael Knyszek <mknyszek@google.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>
2025-05-21internal/trace: skip clock snapshot checks on Windows in stress modeMichael Anthony Knyszek
Windows' monotonic and wall clock granularity is just too coarse to get reasonable values out of stress mode, which is creating new trace generations constantly. Fixes #73813. Change-Id: Id9cb2fed9775ce8d78a736d0164daa7bf45075e0 Reviewed-on: https://go-review.googlesource.com/c/go/+/675096 Reviewed-by: Felix Geisendörfer <felix.geisendoerfer@datadoghq.com> Reviewed-by: Roland Shoemaker <roland@golang.org> Auto-Submit: Michael Knyszek <mknyszek@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2025-05-21internal/trace: add generator tests for sync eventsFelix Geisendörfer
Add generator tests that verify the timestamps for the sync events emitted in the go1.25 trace format and earlier versions. Add the ability to configure the properties of the per-generation sync batches in testgen. Also refactor testgen to produce more realistic timestamps by keeping track of lastTs and using it for structural batches that don't have their own timestamps. Otherwise they default to zero which means the minTs of the generation can't be controlled. For #69869 Change-Id: I92a49b8281bc4169b63e13c030c1de7720cd6f26 Reviewed-on: https://go-review.googlesource.com/c/go/+/653876 Auto-Submit: Michael Knyszek <mknyszek@google.com> Reviewed-by: David Chase <drchase@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Michael Knyszek <mknyszek@google.com>
2025-05-21internal/trace/internal/testgen: make generated trace version configurableFelix Geisendörfer
Replace hard coded references to version.Go122 with the trace version passed to NewTrace. This allows writing testgen tests for newer trace versions. For #69869 Change-Id: Id25350cea1c397a09ca23465526ff259e34a4752 Reviewed-on: https://go-review.googlesource.com/c/go/+/653875 Auto-Submit: Michael Knyszek <mknyszek@google.com> Reviewed-by: Michael Knyszek <mknyszek@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2025-05-21internal/trace: add a validator test for the new clock snapshotsFelix Geisendörfer
Check that the clock snapshots, when expected to be present, are non-zero and monotonically increasing. This required some refactoring to make the validator aware of the version of the trace it is validating. Change-Id: I04c4dd10fe6975cbac12bb0ddaebcec3a5284e7b Reviewed-on: https://go-review.googlesource.com/c/go/+/669715 Auto-Submit: Michael Knyszek <mknyszek@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Michael Knyszek <mknyszek@google.com> Reviewed-by: David Chase <drchase@google.com>
2025-05-21internal/trace: expose clock snapshot timestamps on sync eventFelix Geisendörfer
Add ClockSnapshot field to the Sync event type and populate it with the information from the new EvClockSnapshot event when available. For #69869 Change-Id: I3b24b5bfa15cc7a7dba270f5e6bf189adb096840 Reviewed-on: https://go-review.googlesource.com/c/go/+/653576 Reviewed-by: Michael Knyszek <mknyszek@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: David Chase <drchase@google.com> Auto-Submit: Michael Knyszek <mknyszek@google.com>
2025-05-21runtime,internal/trace: emit clock snapshots at the start of trace generationsFelix Geisendörfer
Replace the per-generation EvEventBatch containing a lone EvFrequency event with a per-generation EvEventBatch containing a EvSync header followed by an EvFrequency and EvClockSnapshot event. The new EvClockSnapshot event contains trace, mono and wall clock snapshots taken in close time proximity. Ignoring minor resolution differences, the trace and mono clock are the same on linux, but not on windows (which still uses a TSC based trace clock). Emit the new sync batch at the very beginning of every new generation rather than the end to be in harmony with the internal/trace reader which emits a sync event at the beginning of every generation as well and guarantees monotonically increasing event timestamps. Bump the version of the trace file format to 1.25 since this change is not backwards compatible. Update the internal/trace reader implementation to decode the new events, but do not expose them to the public reader API yet. This is done in the next CL. For #69869 Change-Id: I5bfedccdd23dc0adaf2401ec0970cbcc32363393 Reviewed-on: https://go-review.googlesource.com/c/go/+/653575 Reviewed-by: David Chase <drchase@google.com> Auto-Submit: Michael Knyszek <mknyszek@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Michael Knyszek <mknyszek@google.com>
2025-02-14internal/trace: emit sync event before deferred spilled errorMichael Anthony Knyszek
CL 648315 and CL 648195 fixed #71615 in the case where we fail to read the next generation by emitting an extra sync event before returning an error. But, it's possible we failed to even read the next spilled batch when we read the first generation, and have been carrying the error from trying to read a spilled batch since the last generation. In this case, we don't emit a final sync event, meaning that there are still some cases where #71615 happens. This change emits the final sync event in this corner case. I believe this is the final corner case. I could previously reproduce the issue by running the test under stress2, but I can no longer reproduce any failures after this change. Fixes #71615, for real this time. Change-Id: I10688a3c0e4b8327a95f31add365338c77c091ab Reviewed-on: https://go-review.googlesource.com/c/go/+/649259 Reviewed-by: Cherry Mui <cherryyz@google.com> Auto-Submit: Michael Knyszek <mknyszek@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2025-02-11internal/trace/tracev2: add guide for trace experimentsMichael Anthony Knyszek
Change-Id: I6fb354a57f3e73bd6589570868c7d68369adcf3c Reviewed-on: https://go-review.googlesource.com/c/go/+/645136 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>
2025-02-11internal/trace: interpret string ID arguments for experimental eventsMichael Anthony Knyszek
Currently one of the reasons experimental events are tricky to use is because: - There's no way to take advantage of the existing infrastructure, like strings and stacks, and - There's no way to attach arbitrary data to an event (except through strings, possibly). Fix this by abstracting away the raw arguments in an ExperimentalEvent and requiring access to the arguments via a new method, ArgValue. This returns a Value, which gives us an opportunity to construct a typed value for the raw argument dynamically, and a way to access existing tables. The type of the argument is deduced from conventions for the argument's name. This seems more than sufficient for experimental events. To make this work, we also need to add a "string" variant to the Value type. This may be a little confusing since they're primarily used for metrics, but one could imagine other scenarios in which this is useful, such as including build information in the trace as a metric, so I think this is fine. This change also updates the Value API to accomodate a String method for use with things that expect a fmt.Stringer, which means renaming the value assertion methods to have a "To" prefix. Change-Id: I43a2334f6cd306122c5b94641a6252ca4258b39f Reviewed-on: https://go-review.googlesource.com/c/go/+/645135 Reviewed-by: Michael Pratt <mpratt@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Auto-Submit: Michael Knyszek <mknyszek@google.com>
2025-02-11internal/trace: move fake P IDs to internal/trace/traceviewerMichael Anthony Knyszek
These fake P IDs really only belong to the traceviewer. Change-Id: I7976beb5750f1efca85e28975074a8c570a9c959 Reviewed-on: https://go-review.googlesource.com/c/go/+/644876 Reviewed-by: Michael Pratt <mpratt@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Auto-Submit: Michael Knyszek <mknyszek@google.com>
2025-02-11internal/trace: clean up parser.goMichael Anthony Knyszek
parser.go is an old file that contains trace v1 definitions and a second equivalent definition for stack frames. These are redundant and useless. Delete these definitions and rename the file to fakep.go, which describes the only thing left in this file, a bunch of fake P IDs used by the trace viewer. We should consider moving the fake P definitions elsewhere, too. Change-Id: Ifd0768bd73c39009069445afe0155f1e352f00c3 Reviewed-on: https://go-review.googlesource.com/c/go/+/644875 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>
generated by cgit v1.3 (git 2.53.0) at 2026-04-15 14:36:08 +0000