perf: fix macOS spawn latency (~120ms → ~12ms)#1
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pi0 merged 2 commits intopithings:mainfrom Apr 8, 2026
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Enumerate /dev/fd instead of brute-force close(3..sysconf limit), which is ~1M no-op syscalls on modern macOS. Also unref Unix exit tsfn to match Windows, cache TextDecoder, add latency benchmark.
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Hi! Just stumbled onto this:
macOS recently bumped
sysconf(_SC_OPEN_MAX)to1,048,575.closeExcessFdswas callingclose()from 3 to that limit in every child process — over a million no-op syscalls per spawn. Now we enumerate/dev/fdinstead (same approach Linux uses with/proc/self/fd).Minor stuff: unref the Unix exit tsfn (Windows already did this), cache a
TextDecoderin Terminal, and addscripts/bench-latency.ts.