go/src/internal/trace/parser.go, branch bench-before

all: prealloc slice with possible minimum capabilities

2024-01-24T21:01:14Z

cmd/trace: add almost full support for v2 traces in the trace viewer

2023-11-21T20:45:06Z

This change refactors the cmd/trace package and adds most of the support for v2 traces. The following features of note are missing in this CL and will be implemented in follow-up CLs: - The focustask filter for the trace viewer - The taskid filter for the trace viewer - The goid filter for the trace viewer - Pprof profiles - The MMU graph - The goroutine analysis pages - The task analysis pages - The region analysis pages This CL makes one notable change to the trace CLI: it makes the -d flag accept an integer to set the debug mode. For old traces -d != 0 works just like -d. For new traces -d=1 means the high-level events and -d=2 means the low-level events. Thanks to Felix Geisendörfer (felix.geisendoerfer@datadoghq.com) for doing a lot of work on this CL; I picked this up from him and got a massive headstart as a result. For #60773. For #63960. Change-Id: I3626e22473227c5980134a85f1bb6a845f567b1b Reviewed-on: https://go-review.googlesource.com/c/go/+/542218 Reviewed-by: Michael Pratt Auto-Submit: Michael Knyszek TryBot-Bypass: Michael Knyszek

runtime: emit STW events for all pauses, not just those for the GC

2023-05-19T17:06:45Z

Currently STW events are only emitted for GC STWs. There's little reason why the trace can't contain events for every STW: they're rare so don't take up much space in the trace, yet being able to see when the world was stopped is often critical to debugging certain latency issues, especially when they stem from user-level APIs. This change adds new "kinds" to the EvGCSTWStart event, renames the GCSTW events to just "STW," and lets the parser deal with unknown STW kinds for future backwards compatibility. But, this change must break trace compatibility, so it bumps the trace version to Go 1.21. This change also includes a small cleanup in the trace command, which previously checked for STW events when deciding whether user tasks overlapped with a GC. Looking at the source, I don't see a way for STW events to ever enter the stream that that code looks at, so that condition has been deleted. Change-Id: I9a5dc144092c53e92eb6950e9a5504a790ac00cf Reviewed-on: https://go-review.googlesource.com/c/go/+/494495 Reviewed-by: Michael Pratt TryBot-Result: Gopher Robot Run-TryBot: Michael Knyszek

runtime/trace: update outdated Task and Region documentation

2023-03-09T19:10:52Z

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 Reviewed-by: Carlos Amedee Auto-Submit: Michael Pratt Run-TryBot: Michael Pratt TryBot-Result: Gopher Robot Run-TryBot: Nick Ripley

runtime: fix cpu sample comment

2023-02-06T22:13:07Z

Fixes #58327 Change-Id: I15593e6ee42e04f2de13804ef26e0e66a2307db0 GitHub-Last-Rev: 7e0d04b503d2ba217b76b1ac668a67cd72ec6d7c GitHub-Pull-Request: golang/go#58338 Reviewed-on: https://go-review.googlesource.com/c/go/+/465335 Reviewed-by: Michael Knyszek Run-TryBot: Michael Knyszek Auto-Submit: Michael Knyszek Reviewed-by: David Chase TryBot-Result: Gopher Robot

internal/trace: use strings.Builder

2022-09-06T12:35:13Z

Change-Id: Ic7f827b8ee758c991ed76be65026b0330207deea Reviewed-on: https://go-review.googlesource.com/c/go/+/428262 Reviewed-by: Ian Lance Taylor TryBot-Result: Gopher Robot Run-TryBot: Ian Lance Taylor Auto-Submit: Ian Lance Taylor Reviewed-by: Michael Pratt

internal/trace: add Go 1.19 test data

2022-06-24T22:08:17Z

Update instructions to match what seems to be the historical practice: to generate canned traces when a version is finalized, rather than waiting until it is superseded. Follow rename of trace-internal tests from "Span" to "Region". Update the net/http test invocation to match the apparent intent and the actual http_1_5_good behavior (about 7ms of total run time and trace file size under 50kB). Change-Id: Ifd4c85882159478852e0b8f0d771b6f16b8f3c1b Reviewed-on: https://go-review.googlesource.com/c/go/+/413776 Run-TryBot: Rhys Hiltner Reviewed-by: Carlos Amedee TryBot-Result: Gopher Robot Reviewed-by: Michael Pratt

runtime: add CPU samples to execution trace

2022-05-03T20:49:46Z

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 Run-TryBot: Rhys Hiltner Reviewed-by: David Chase TryBot-Result: Gopher Robot

runtime: move next_gc and last_next_gc into gcControllerState

2021-04-14T14:03:30Z

This change moves next_gc and last_next_gc into gcControllerState under the names heapGoal and lastHeapGoal respectively. These are fundamentally GC pacer related values, and so it makes sense for them to live here. Partially generated by rf ' ex . { memstats.next_gc -> gcController.heapGoal memstats.last_next_gc -> gcController.lastHeapGoal } ' except for updates to comments and gcControllerState methods, where they're accessed through the receiver, and trace-related renames of NextGC -> HeapGoal, while we're here. For #44167. Change-Id: I1e871ad78a57b01be8d9f71bd662530c84853bed Reviewed-on: https://go-review.googlesource.com/c/go/+/306603 Trust: Michael Knyszek Run-TryBot: Michael Knyszek TryBot-Result: Go Bot Reviewed-by: Michael Pratt

runtime/trace: rename "Span" with "Region"

2018-04-24T16:33:15Z

"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 TryBot-Result: Gobot Gobot Reviewed-by: JBD