golang/go

runtime: TestRuntimeLockMetricsAndProfile/runtime.lock failures

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#70602 opened on Nov 27, 2024

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Description

#!watchflakes
default <- test ~ `TestRuntimeLockMetricsAndProfile/runtime.lock/` ||
    log ~ `panic: test timed out after 5m0s(.|\n)+TestRuntimeLockMetricsAndProfile/runtime.lock/sample-\d \(4m`

Issue created automatically to collect these failures.

Example (log):

=== RUN   TestRuntimeLockMetricsAndProfile/runtime.lock/sample-1
    metrics_test.go:1065: lock contention growth in runtime/pprof's view  (1.241778s)
    metrics_test.go:1066: lock contention growth in runtime/metrics' view (1.241730s)
    metrics_test.go:1104: stack [runtime.unlock runtime_test.TestRuntimeLockMetricsAndProfile.func5.1 runtime_test.(*contentionWorker).run] has samples totaling n=199 value=1207128831
    metrics_test.go:1192: mutex profile reported contention count different from the known true count (199 != 200)
--- FAIL: TestRuntimeLockMetricsAndProfile/runtime.lock/sample-1 (1.25s)

— watchflakes

Contributor guide

Tech stack
go
Domain
testingbackend
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
5
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
over 1 week
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
None
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
10
Research direction
This issue tracks a flaky test failure in the Go runtime's metrics test, specifically `TestRuntimeLockMetricsAndProfile/runtime.lock` in `src/runtime/metrics test.go`. The failure involves lock contention growth discrepancies between `runtime/pprof` and `runtime/metrics`. The issue has an assignee and ongoing discussion; newcomers should examine the linked logs and test code to understand the race condition, but this is not suitable for first time contributors due to deep runtime knowledge required.