Files
LEDMatrix/src
ChuckBuildsandClaude Opus 5 0fd2bfae99 perf(plugins): stop rewriting a plugin's metrics file on every call
Plugin metrics were persisted to the cache inside monitor_call, so every
call by every plugin rewrote a small JSON file. Measured on a running rig:
one plugin's plugin_metrics file changed nine times a minute, with fourteen
such files active. Each is around 350 bytes, which on ext4 costs a 4KB block
plus a journal entry, so the cost is dominated by the write itself rather
than the payload. Cache writes accounted for essentially all of that device's
2.4 MB/min of SD traffic, on a card that wears out and has already failed
twice on the other rig.

Metrics cannot be de-duplicated the way health state can, because call_count
changes on every call and the timings usually do too. So they are rate-limited
instead: at most one write per plugin per 30 seconds.

The in-memory copy stays authoritative and exact -- a plugin's call_count is
still precise the instant after it runs. Only the cross-process snapshot the
web UI reads is delayed, and telemetry up to half a minute old is still a fair
description of a long-running plugin.

reset_metrics clears the throttle timestamp, so a reset is not left showing a
deleted key for the rest of the interval.

Extrapolating the sampled rate, this takes metric writes from roughly 126 a
minute to 28. Health persistence, the other half of the churn, is handled
separately in #475.

Verified by reverting the throttle: the churn test then reports 50 writes for
50 calls. 88 tests pass across resource monitor, plugin system and web API.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01STMbQE4YctTacQXfbYqKuW
2026-08-20 07:06:21 -04:00
..
2025-12-27 14:15:49 -05:00