XPerf
LanguagesSwiftEvidence

sp-json-decode-hot — measured, still hint

Status

hint. Wall-clock JSONL: sp-json-decode-hot.jsonl. Not corpus-triaged. The 2026-10-22 corpus verdict does not cover this slug.

Measurement

20000 decodes of one fixed JSON object. After decodes once and rereads the field. A changing payload cannot use this after shape.

rolecasemedian_msopsratio
afterdecode_once0.011086200001
beforedecode_each_iter21.706939200001957.968

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.