v134 · privacy sandbox / storage

Lock Contention Probe

Run multiple worklet-shaped tasks racing to read-check-write a "seen" flag. Without locks, concurrent tasks all see false and over-report. With real navigator.locks.request(), they queue and only the first reports — eliminating duplicates.

checking Web Locks API…

The bug: worklet A reads seen = false, worklet B reads seen = false (before A writes), both report. Chrome 134 lets worklets call navigator.locks.request('reach-lock', async () => { … }) — only one holds the lock at a time, so the second worklet reads the updated value and skips.

Probe settings

Worklets: 6

Critical section time

Mode

Worklet states

—

Total worklets

—

Duplicate reports

—

Unique reports

—

Total time (ms)

Execution log

Configure and click "Run probe".