maze32/docs/M016_LATENCY_PROCEDURE.md

Milestone 016 movement-latency procedure

Measurement model

Each accepted movement uses one correlation path. Browser times use performance.now() and ESP times use its monotonic timer; do not subtract a browser timestamp from an ESP timestamp.

Interval	Clock	Measurement point
pointer feedback	browser	pointer event to next animation frame
command to acknowledgement	browser	move send to matching ack
command to complete view	browser	move send to matching assembled view sequence
command to painted view	browser	move send to next frame after matching view render
handler and send	ESP	existing /diagnostics maxima
network round trip	client	ICMP and WebSocket heartbeat samples
ESP heartbeat handling	ESP	bounded acknowledgement preparation interval

The accepted command acknowledgement contains the authoritative stateSequence. The browser records a sample only after the complete view with that sequence is rendered and the next animation frame occurs. Samples are local-only, capped at 256, and do not alter a command, projection, or server result.

Controlled runs

1. Record the firmware build identity, device address, Wi-Fi access point, client device, browser/version, signal conditions, and viewport.
2. Collect 100 ping -c 100 -q <device> samples. Record loss, min, average, maximum, and deviation.
3. Run 200 accepted moves per player with two players and no observers. Include direction changes, a sustained hold, a release, and one blocked move.
4. Repeat with two players and four observers. Capture /diagnostics before and after each run.
5. For each browser, copy window.maze32PlayerApp.latencySamples() after the run. Compute p50, p95, p99, and maximum for all browser intervals. Keep raw samples only for the duration of the report and do not store player names or tokens.
6. Compare command-to-acknowledgement with command-to-painted-view, ESP handler and send maxima, queue high-water marks, observer view chunk count, and ICMP/WebSocket round trips. Attribute a delay only when the matching interval is elevated.
7. For the compact quality indicator, record the rounded Отклик, Связь, and ESP values after the five-second heartbeat cadence has collected a fresh sample. Связь is the non-negative round-trip remainder, not a pure Wi-Fi measurement.

Safety checks

• Confirm no dropped, failed, malformed, oversized, or rate-limited message increased unexpectedly outside the deliberate blocked-move case.
• Confirm queue high water stays within its published limit and browser sample storage remains at or below 256 entries.
• Record blocked-command rejection separately; it does not count as an accepted-move sample.