Custom ASV Flags

How to pass extra flags to asv-spyglass through the action.

Using asv-spyglass-args

The asv-spyglass-args input passes additional flags directly to the asv-spyglass CLI invocation:

- name: Post benchmark comment
  uses: HaoZeke/asv-perch@v1
  with:
    github-token: ${{ secrets.GITHUB_TOKEN }}
    results-path: results/
    metadata-file: results/metadata.txt
    asv-spyglass-args: '--split --only-changed --factor 1.05'

Available Flags

These are asv-spyglass flags (not action inputs). Consult asv-spyglass --help for the full list. Commonly used:

Flag	Effect
--split	Split output into separate tables by change type
--only-changed	Show only benchmarks that changed
--only-regressed	Show only regressions
--factor N	Set significance factor (default 1.1 = 10%)
--sort ratio	Sort benchmarks by ratio
--sort name	Sort benchmarks by name
--no-env-label	Omit environment labels from benchmark names

–split Output

When --split is used, asv-spyglass outputs multiple tables separated by section headers. The action’s parser handles this correctly – it skips non-table lines and merges all data rows from all tables into a single result.

–factor

The factor parameter controls ASV’s significance threshold. A factor of 1.1 means changes less than 10% are not considered significant. Lower values (e.g., 1.05) are stricter.

This is different from regression-threshold – factor affects which benchmarks asv-spyglass marks as changed (+ or -), while regression-threshold controls which regressions the action considers “critical” for gating.

When asv-spyglass-args Is Not Enough

If you need more control than asv-spyglass-args provides (e.g., custom Python path, environment variables, specific asv-spyglass version), use the comparison-text-file input instead and run asv-spyglass yourself:

- name: Run comparison with full control
  run: |
    pixi run -e bench uvx --from "asv-spyglass==1.2.3" \
      asv-spyglass compare base.json pr.json \
      --factor 1.02 --split --sort ratio --no-env-label \
      > comparison.txt

- name: Post results
  uses: HaoZeke/asv-perch@v1
  with:
    github-token: ${{ secrets.GITHUB_TOKEN }}
    comparison-text-file: comparison.txt