sootsim perf
sootsim perf
One profiling group for sampled JS CPU profiles, React render-cost tables, shell and compositor frame timing, and timestamp-aligned scroll offsets from the tenant, shell, and compositor workers.
terminal
Options
| flag | description |
|---|---|
--cdp-port <port> | for perf cpu: Chrome DevTools port (default: $SOOTSIM_CDP_PORT or 9222) |
--duration <seconds> | for perf cpu: recording duration (default: 5) |
--match <substring> | for perf cpu: pick the page target by URL substring |
--output <path> | for perf cpu: output .cpuprofile path |
--include-props | for perf react profile start: record shallow prop previews |
--limit <n> | for perf react: rows; for perf scroll: samples per layer |
--json | structured output where supported |
--sim <sim> | target a specific connected sim |
Examples
terminal
Profiling Surfaces
perf cpu captures sampled JavaScript CPU profiles through CDP. Open the sim with a CDP port first:
terminal
perf react reads React render cost from the tenant worker. perf shell records shell and compositor frame timing. perf scroll records timestamp-aligned per-frame offsets from the tenant, shell, and compositor workers while it is armed; use --json on stop for the complete series.

