{
  "slug": "hyperfine-reference-selects-a-benchmark-by-exact-displayed-name-in-parameter-sca-b91c6ed2bfc9",
  "title": "hyperfine --reference selects a benchmark by exact displayed name in parameter scans",
  "tools": [
    "hyperfine"
  ],
  "tags": [
    "agent"
  ],
  "introduced_at": "2026-10-05T14:11:15.000Z",
  "announced_at": "2026-10-05T14:11:15.000Z",
  "effective_at": null,
  "date_basis": "source-publication",
  "status": "unknown",
  "how": {
    "incantation": "When scanning or listing parameterized benchmarks, pass `--reference` with the exact printed name of one benchmark in that invocation. Use `--command-name` to name a benchmark; `--reference-name` cannot be used with parameterized benchmarks.",
    "examples": [
      "hyperfine --parameter-scan <VAR> <MIN> <MAX> --command-name '<benchmark name>' '<parameterized command using {VAR}>' --command-name '<reference name>' '<reference command>' --reference '<reference name>'",
      "hyperfine --parameter-list <VAR> <comma-separated-values> --command-name '<benchmark name>' '<parameterized command using {VAR}>' --command-name '<reference name>' '<reference command>' --reference '<reference name>'"
    ],
    "gotchas": [
      "Version: v1.21.0",
      "--parameter-scan <VAR> <MIN> <MAX>: Benchmark each value in MIN..MAX, substituting `{VAR}` in commands. Use for a parameter scan.",
      "--parameter-list <VAR> <VALUES>: Benchmark each comma-separated value, substituting `{VAR}` in commands. Use for a parameter list.",
      "--reference <CMD> (required): With a parameter scan or list, select an existing benchmark by its exact printed name; it must match exactly one benchmark.",
      "--command-name <NAME>: Give a command a meaningful name; can be specified multiple times for multiple commands. Use this instead of `--reference-name` with parameterized benchmarks.",
      "--reference-name <NAME>: Names a reference command and requires `--reference`; cannot be used with parameterized benchmarks. Use `--command-name` instead. These options are incompatible in this mode.",
      "The full displayed name must match exactly one benchmark.",
      "This behavior applies with `--parameter-scan` or `--parameter-list`.",
      "Use `--command-name` instead of `--reference-name` in this mode."
    ]
  },
  "why_it_matters": "Use an existing benchmark as the reference while scanning or listing parameterized commands.",
  "before": "Previously, `--reference` ran a separate reference command; with `--parameter-scan` or `--parameter-list`, it now selects an existing benchmark by its full displayed name.",
  "sources": [
    "https://github.com/sharkdp/hyperfine/releases/tag/v1.21.0",
    "https://github.com/sharkdp/hyperfine/blob/v1.21.0/doc/hyperfine.1"
  ],
  "rank": 0.96027,
  "judge": {
    "publish": true,
    "judge_model": "codex-cli/gpt-6-luna+typesafe/jev-1.13.0",
    "prompt_version": "extract-v7+enrich-v2+judge-v2x3+jev-publish-v1"
  },
  "review_state": "approved",
  "provenance": {
    "run_id": "wave2b-20261017",
    "verdict_id": "wave2b-20261017:wave2b-20261017-ef6beaaba4888164-4:gate",
    "evidence_hash": "d4af82ee180cf3c093e5b8093dfcb0a30fe5e03780bb7b16c9cc3d0bd2568623"
  },
  "review": {
    "draft_hash": "eda3dd3f1b8f0436535b002ee1adfc831034bc5e0cd879c9abcd31543d0689fc",
    "reviewer": "publication-gate",
    "reviewed_at": "2026-10-07T00:00:00.000Z",
    "decision": "wave2b-20261017:gate",
    "reason": "3 of 3 judge runs approved with p_yes >= 0.9 (mean 0.96 >= 0.9; 2 needed) and Jev gave 0.63 (>= 0.6 needed)."
  }
}