performance slopping but actually very informative

2026-09-16 01:21:20 -04:00 · 2026-06-11 14:07:28 -04:00
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+# `/` CPU Performance Issue Index
+
+This folder breaks the live-site `/` CPU investigation into separate, work-ready issues.
+Each issue can be handled in its own chat or branch without needing to re-run the whole
+investigation first.
+
+The testing target was the deployed page:
+
+```sh
+https://rover.otter.land/
+```
+
+The important local perf tools are:
+
+```sh
+node perf/live-cpu-profile.mjs https://rover.otter.land/ perf/results
+node perf/live-listener-audit.mjs https://rover.otter.land/ perf/results
+CPU_THROTTLE=6 VIEWPORT=390x844 MOBILE=1 SAMPLE_MS=30000 node perf/live-root-runtime-audit.mjs https://rover.otter.land/ perf/results
+```
+
+The strongest `/` artifacts from this investigation are:
+
+- `perf/results/2026-06-11T03-15-51-398Z/report.json`
+  Clean `/` profile, mobile viewport, 8x CPU throttle.
+- `perf/results/2026-06-11T03-03-31-625Z-listeners/listener-report.json`
+  Listener add/remove stack audit.
+- `perf/results/2026-06-11T03-21-51-263Z-root-runtime/root-runtime-report.json`
+  `/` runtime audit, mobile viewport, 6x CPU throttle, 30s sample.
+- `perf/results/2026-06-11T03-22-44-714Z-root-runtime/root-runtime-report.json`
+  `/` runtime audit, mobile viewport, 6x CPU throttle, 18s sample with mutation targets.
+
+## Ranked Issues
+
+1. [Global input listener churn](./001-global-input-listener-churn.md)
+2. [ControlContext broad invalidation](./002-control-context-broad-invalidation.md)
+3. [High-volume socket log stream](./003-high-volume-log-stream.md)
+4. [Sensor telemetry render frequency](./004-sensor-telemetry-render-frequency.md)
+5. [ReplaySourcesPanel repeated DOM commits](./005-replay-sources-panel-churn.md)
+6. [Chat and nickname composer churn](./006-chat-and-nickname-churn.md)
+7. [Timers and polling cleanup](./007-timers-and-polling.md)
+
+## Quick Read
+
+The highest-confidence first fix is issue 001. It is directly measured, large, and
+structurally fixable: install keyboard/gamepad global listeners once and have them read
+latest state/actions from refs.
+
+Issue 002 is the likely multiplier behind issue 001 and several UI churn symptoms. The
+current `ControlContext` value changes broadly, and many callbacks depend on `state` or
+`pipeline`; that causes consumers/effects to refresh even when the visible behavior did
+not materially change.
+
+Issues 003 and 004 are independent live-data pressure: the `/` page receives a lot of
+socket traffic, especially `log:entry` and `sensorFrame`, and those streams feed UI work.
+
+Issue 005 and issue 006 are component-level symptoms visible in DOM mutation probes. They
+should probably be tackled after the context/listener work, because broad invalidation may
+be causing some of their repeated commits.
+
+## Important Scope Note
+
+There are also `/spectate` results in `perf/results` because the investigation briefly
+compared routes. The user later clarified that `/spectate` is not the current priority.
+These issue writeups intentionally focus on `/` only.
+