gp-os-open-hot — measured, still hint
Status
hint. Wall-clock JSONL: gp-os-open-hot.jsonl. Not corpus-triaged. The 2026-10-22 corpus verdict does not cover this slug.
Measurement
os.Open plus a short read of one one-byte file, 2000 times, versus opening once.
| role | case | median_ms | ops | ratio |
|---|---|---|---|---|
| after | open_once | 0.031917 | 2000 | 1 |
| before | open_each_iter | 14.717375 | 2000 | 461.114 |
go1.27.3, 2026-10-23. Warm 3, median of 9. After opens and reads once.
The bench reopens one one-byte file. A path that changes every iteration cannot be hoisted; the measured cost is the open and read. Default stays hint. This ratio is not a general speedup.
Unblock
Do not set the default to error from this file alone. A changing input, a cold path, or another ABI can erase the difference. Corpus triage is still required before any default change.