"go test -race" Under the Hood
summary
The go race detector claims to find real data races by having the compiler insert calls around memory and sync operations and by delegating detection to ThreadSanitizer (tsan) which implements a happens-before check using vector clocks. Instrumentation adds race_read/race_write calls and the runtime keeps compact shadow state — only 4 shadow cells per 8-byte application word and scalar clocks — so reports have no false positives but can miss races on unobserved executions and impose significant runtime and memory overhead, so it’s mainly for tests and staging.
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chapters (13)
- 0:00Intro
- 1:26data races
- 5:18race detectors
- 6:27go race detector
- 7:58concurrency in go
- 14:41vector clocks
- 20:00go run -race
- 25:24threadsanitizer
- 27:01shadow state
- 29:33race detection
- 32:55evaluation
- 36:31Optimization 1
- 38:17alternatives
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