perf(runner): run inline when no random delay is configured#565
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Every fire was wrapped in setTimeout(fn, randomDelay) to apply jitter, but with the default maxRandomDelay of 0 the delay is always 0, so the timer only added a macrotask hop (and ~1ms+ of avoidable firing drift) with no effect. Run the task inline on the heartbeat's own tick when no jitter is configured, and keep the timer only when a positive delay is set. The next heartbeat is armed before the execution runs, so timing is unaffected.
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What
Run the task inline on the heartbeat tick when no random delay is configured, instead of always wrapping it in
setTimeout(fn, randomDelay).Why
The per-fire
setTimeoutexists to apply a random jitter, but the defaultmaxRandomDelayis 0, so the delay is always 0 and the timer only adds a macrotask hop (and ~1ms+ of avoidable firing drift) with no effect. The timer is kept when a positive delay is configured. The next heartbeat is armed before the execution runs, so scheduling timing is unaffected.Impact
Notes