contextcond

This library provides a sync.Cond that has a WaitContext() method.

WaitContext(context.Context) waits for either the condvar to wake it, or the context to be cancelled. It returns nil if the condvar woke it, or ctx.Err() if the context was cancelled.

Benchmark

contextcond is slower than sync.Cond, so you should only use it if you need WaitContext().

$ go test -bench .
goos: linux
goarch: amd64
pkg: github.com/Jille/contextcond
cpu: Intel(R) Xeon(R) CPU E5-2650 0 @ 2.00GHz
BenchmarkCond1-8          560541              1968 ns/op
BenchmarkCond2-8          196060              7049 ns/op
BenchmarkCond4-8           95750             12685 ns/op
BenchmarkCond8-8           49628             25710 ns/op
BenchmarkCond16-8          34155             37504 ns/op
BenchmarkCond32-8          14602             82923 ns/op

Compared to sync.Cond:

$ go test -bench . /usr/lib/go-1.19/src/sync/cond_test.go
goos: linux
goarch: amd64
cpu: Intel(R) Xeon(R) CPU E5-2650 0 @ 2.00GHz
BenchmarkCond1-8         1509849               782.1 ns/op
BenchmarkCond2-8          447687              2589 ns/op
BenchmarkCond4-8          251739              5226 ns/op
BenchmarkCond8-8          118968             11194 ns/op
BenchmarkCond16-8          44931             24098 ns/op
BenchmarkCond32-8          28124             40405 ns/op