timestamp-query

Timestamp queries write GPU clock values at pass boundaries into a GPUQuerySet, which you resolve into a buffer and read back. That gives per-pass GPU timings - the foundation of any serious frame profiler or auto-tuning system that picks workgroup sizes based on measured performance.

Browsers quantize the timestamps to mitigate timing-based fingerprinting and side channels, so the resolution is good enough for profiling passes but deliberately not nanosecond-exact. CPU/GPU clock domains also differ; only differences between GPU timestamps are meaningful.

It is one of the most widely supported optional features on desktop, but notably absent on some mobile drivers - check the by-browser and by-vendor splits below.