Criterion Performance Comparison for GitHub Actions

⚠️ WARNING: Performance benchmarks provided by this action may fluctuate up to 50% on cloud infrastructure. Run benchmarks locally or on a dedicated test runner before making any decisions based on the results.

This Github action compares performance between a PR and a dedicated target branch (usually the master or main branch).

Usage

Quickstart

Create a .github/workflows/pull_request.yml workflow file in your repo:

# in file: .github/workflows/pull_request.yml
on: [pull_request]
name: Benchmark Pull Request
jobs:
  runBenchmark:
    name: run benchmark
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@master
      - uses: chipbuster/criterion-compare@vX.Y.Z
        with:
          cwd: subDirectory (optional)
          benchName: my-criterion-benchmark
          branchName: trunk
          token: ${{ secrets.GITHUB_TOKEN }}

You should now get a comment on new PRs for performance!

Options

This action supports the following options passed via the with parameter:

token

The GitHub token which provides access to the repo (specifically, to comment). You don't need to do anything special for this aside from provide the string ${{ secrets.GITHUB_TOKEN }} as in the example: GitHub has already generated this token for you.

workDir (default: ./)

The working directory relative to the project root. Useful if your project is not in the repository root (e.g. if you have multiple crates in one repo).

cargoBenchName (default: none)

The name of the cargo benchmark to run. If not provided, is not passed to cargo bench, resulting in all benchmarks being run.

gitBranchName (default: ${{ github.base_ref }})

The name of the branch to use as the baseline performance. Will usually be the branch that the PR wants to merge into, or another stable branch (like main or trunk).

If not provided, defaults to the base_ref, i.e. the branch that is being merged to.

doFetch (default: true)

The default checkout action only checks out the ref that causes the PR. This action needs a reference to gitBranchName in order to do the benchmarks, so we usually have to perform a fetch before running benchmarks.

If you need to disable this behavior, you can set doFetch to false. Just make sure you've gotten the branch referred to by gitBranchName in some other way, e.g. by passing parameters to a checkout action before this one.

doClean (default: false)

Whether to run cargo clean before executing benchmarks. Should not be needed most of the time.

doComment (default: true)

Whether to post a comment to the repository describing the results. Defaults to true. However, if you want to aggregate results (e.g. with a different benchmark suite), you can set this to false. The benchmark results will be available in the outputs results_markdown and results_json, respectively.

Troubleshooting

Unrecognized option: 'save-baseline'

Check out the upstream docs for criterion here to get the full details of what's going on and the fixes. The short version is that this is caused by an issue with cargo bench and you currently have two options for a fix:

• Pass the benchname to this action with cargoBenchName. This works only if there is a single benchmark you want to run.
• Disable benchmarks for your lib/bin crates by adding bench = false to the appropriate locations in your Cargo.toml.

Known Limitations

This action cannot handle mismatched repository structures between two branches, e.g. if the code structure has been changed between the PR and the base branch, the action will likely fail.