rubyperf Ruby performance guide (v0)rubyperf rule ids (slugs)rubyperf corpus targets rubyperf evidence policy

rb-array-plus-rebind — a = a + [x] vs <<rb-file-read-hot — measured, still hint rb-json-hot — measured, still hint rb-puts-hot — puts each vs join once rb-regexp-new-hot — measured, still hint rb-string-plus-hot — string += vs <<

rb-date-parse-in-loop rb-date-parse-in-loop — removed 2026-10-23 (Asia/Shanghai)rb-file-read-in-loop — renamed 2026-10-27 (Asia/Shanghai)rb-hash-merge-in-loop — Hash#merge in loop vs build-once rb-hash-merge-in-loop — removed 2026-10-23 (Asia/Shanghai)rb-json-in-loop — renamed 2026-10-27 (Asia/Shanghai)rb-puts-in-loop — renamed 2026-10-27 (Asia/Shanghai)rb-regexp-new-in-loop — renamed 2026-10-27 (Asia/Shanghai)rb-string-plus-in-loop — renamed 2026-10-27 (Asia/Shanghai)

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Contributing Changelog Security Policy Contributor Covenant Code of Conduct AGENT.md — XPerf agent operating contract

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rb-date-parse-in-loop — removed 2026-10-23 (Asia/Shanghai)

Status: removed. Time.parse on one fixed string was about 604× only because the after side did not parse. A changing string has no parser object to reuse, and the matcher cannot tell those cases apart.

Slug never reused.
No active matcher.

rb-date-parse-in-loop

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