EventsPerSecond is updated on every captured frame, every detection and
every processed frame across all cameras and detectors. The previous
implementation derived timestamps from datetime.now().timestamp() (wall
clock), so an NTP or manual clock adjustment could skew the rolling-window
expiry; it also stored timestamps in a list and expired them with
del self._timestamps[0] (O(n) per removal) plus a periodic slice-copy to
cap growth.
Switch to time.monotonic() for the interval math (correct by construction
and immune to wall-clock jumps) and a collections.deque(maxlen=...) so
expiry is O(1) (popleft) and retention is bounded automatically. This
mirrors the deque-based expiry already used in video/ffmpeg.py and
watchdog.py. Observable output is unchanged.
Adds frigate/test/test_builtin.py covering rate calculation, window
expiry and the memory bound.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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