golang/go

runtime:cpu1: TestPreemptionAfterSyscall/100µs failures

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#72965 opened on Mar 20, 2025

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AutomationNeedsInvestigationcompiler/runtimehelp wanted

Description

#!watchflakes
default <- pkg == "runtime:cpu1" && test == "TestPreemptionAfterSyscall/100µs"

Issue created automatically to collect these failures.

Example (log):

=== RUN   TestPreemptionAfterSyscall/100µs
    proc_test.go:1082: timeout exceeded: 6.015091541s (5s)
--- FAIL: TestPreemptionAfterSyscall/100µs (12.08s)

— watchflakes

Contributor guide

Tech stack
go
Domain
backendperformance
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.
needs investigation
Prerequisites
Go programmingRuntime scheduler concepts
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
10
Research direction
Investigate the flaky test 'TestPreemptionAfterSyscall/100µs' in proc test.go. The test times out, indicating a possible issue with goroutine preemption during syscall. Review recent commits to the Go scheduler (e.g., runtime/proc.go) and related issues. Check if the failure is platform specific (cpu1) and try to reproduce locally. Look for discussions in the comments for hypotheses about root causes or proposed fixes.