bench.yml

name: Benchmark

on:
  push:
    branches: [main]
  pull_request:

permissions:
  contents: write      # needed for auto-push to gh-pages on main branch
  pull-requests: write # needed for posting benchmark regression comments

concurrency:
  group: bench-${{ github.event.pull_request.number || github.ref }}
  cancel-in-progress: true

env:
  CARGO_TERM_COLOR: always

jobs:
  benchmark:
    name: Performance regression check
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Install Rust (stable)
        run: |
          rustup toolchain install stable --profile minimal --no-self-update
          rustup default stable

      - name: Cache cargo registry & target
        uses: actions/cache@v4
        with:
          path: |
            ~/.cargo/registry
            ~/.cargo/git
            target
          key: bench-${{ runner.os }}-${{ hashFiles('Cargo.toml', 'Cargo.lock') }}
          restore-keys: |
            bench-${{ runner.os }}-

      - name: Run benchmarks
        run: cargo bench --bench rust_bench -- --output-format bencher | tee output.txt

      - name: Reset Cargo.lock changes
        run: git checkout -- Cargo.lock

      - name: Ensure gh-pages branch exists
        run: |
          if ! git ls-remote --exit-code --heads origin gh-pages; then
            echo "Creating gh-pages branch..."
            git checkout --orphan gh-pages
            git reset --hard
            git commit --allow-empty -m "Initialize gh-pages branch for benchmark data"
            git push origin gh-pages
            git checkout -
          fi

      - name: Store benchmark result
        uses: benchmark-action/github-action-benchmark@v1
        with:
          tool: cargo
          output-file-path: output.txt
          github-token: ${{ secrets.GITHUB_TOKEN }}
          auto-push: ${{ github.ref == 'refs/heads/main' }}
          comment-on-alert: true
          alert-threshold: '105%'
          fail-on-alert: false
          gh-pages-branch: gh-pages
          benchmark-data-dir-path: dev/bench