Live metrics (--profile):
- New metricsTracker instruments OnPTYOut, viewport renderer,
stdout writes, libghostty-vt Write/Title CGO calls, sidebar /
tabbar / status draws (with cache-hit accounting), snapshot
replays, and the chrome ticker (so we can see ticker fires that
did nothing).
- Writes metrics.jsonl (one snapshot per second) and metrics.json
+ summary.txt on exit, alongside the existing pprof files.
- All record* methods are nil-safe so disabled paths pay only a
cheap nil check; counters are atomic so the per-PTY-chunk hot
path stays lock-free.
Benchmark suite (go test -bench=.):
- Three workload fixtures — plain ASCII, SGR-styled lines, and a
ratatui-style cursor-shuffling burst — plus a containsOSC
microbenchmark. Reports ns/op, MB/s, allocs/op, B/op.
- Initial baseline numbers added to TODO under the perf-audit
section, alongside two new findings (renderer allocs ~1 per 4
bytes on styled chunks; styled throughput tops out near
90 MB/s) those benchmarks surfaced.
Harry Bayliss
1c590f8e32