cs-format-hot — measured, still hint
Status
hint. Wall-clock JSONL: cs-format-hot.jsonl. Not corpus-triaged. The 2026-10-22 corpus verdict does not cover this slug.
Measurement
50000 iterations. Before calls string.Format for the loop index; after calls Int32.ToString. Both allocate a string. .NET 10.0.13, linux x64, load 0.08. The first three ToString samples were 0.49–0.69 ms and the rest sat near 0.29 ms; the median is 0.3132 ms. Format samples were 1.53–1.59 ms. The earlier .NET 8 pair was about 13.7×.
| role | case | median_ms | ops | ratio |
|---|---|---|---|---|
| after | tostring | 0.3132 | 50000 | 1 |
| before | format_each_iter | 1.565 | 50000 | 4.997 |
The microbench shows a cost for this one shape. Default stays hint until the shape is corpus-triaged. 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.