bench.yml

name: Benchmarks

on:
  pull_request:
    branches: [main]

env:
  CARGO_TERM_COLOR: always

jobs:
  benchmark:
    name: Benchmark (${{ matrix.os }})
    runs-on: ${{ matrix.os }}
    strategy:
      matrix:
        os: [ubuntu-latest, macos-latest]
    permissions:
      contents: write
      pull-requests: write
    steps:
      - name: Checkout PR
        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
        with:
          persist-credentials: false
      - uses: dtolnay/rust-toolchain@0f1b44df7e9cbb178d781a242338dfa5e243ad7f # nightly
      - name: Detect CPU model (cache key + diagnostics)
        id: cpu
        run: |
          if [ "$RUNNER_OS" = "Linux" ]; then
            model=$(grep -m1 'model name' /proc/cpuinfo | cut -d: -f2 | xargs)
          else
            model=$(sysctl -n machdep.cpu.brand_string 2>/dev/null || echo "unknown")
          fi
          echo "model=$model"
          echo "hash=$(echo "$model" | shasum -a 256 | cut -c1-8)" >> "$GITHUB_OUTPUT"
      - uses: Swatinem/rust-cache@e18b497796c12c097a38f9edb9d0641fb99eee32 # v2
        with:
          prefix-key: "bench-${{ steps.cpu.outputs.hash }}"
      - name: Allow perf_event_open (Linux)
        if: runner.os == 'Linux'
        run: sudo sysctl -w kernel.perf_event_paranoid=1
      # ── Seqlock benchmarks (Criterion) ──
      # IMPORTANT: Each Criterion bench must be converted IMMEDIATELY after running,
      # before the next `rm -rf target/criterion`. The criterion-to-json.sh script
      # reads from target/criterion/<group>/ and uses prefix matching on the bench name.
      # If conversion runs after a later bench clears + overwrites criterion/, it will
      # pick up the wrong bench's data.
      - name: Clear Criterion cache before seqlock bench
        run: rm -rf target/criterion
      - name: Run seqlock benchmarks
        run: cargo +nightly bench --bench seqlock
        env:
          RUSTFLAGS: "-C target-cpu=native"
      - name: Convert seqlock Criterion results to JSON report
        run: bash .github/scripts/criterion-to-json.sh seqlock
      - name: Convert seqlock report for CI tracking
        run: |
          jq '[.results[] | {name: ("seqlock/" + .workload), unit: "ns/op", value: .ns_per_op}]' \
            target/bench-report-seqlock.json > bench-output-seqlock.json

      # ── Fixed-point benchmarks (Criterion) ──
      - name: Clear Criterion cache before fixed-point bench
        run: rm -rf target/criterion
      - name: Run fixed-point benchmarks
        run: cargo +nightly bench --bench fixed
        env:
          RUSTFLAGS: "-C target-cpu=native"
      - name: Convert fixed-point Criterion results to JSON report
        run: bash .github/scripts/criterion-to-json.sh fixed
      - name: Convert fixed-point report for CI tracking
        run: |
          jq '[.results[] | {name: ("fixed/" + .workload), unit: "ns/op", value: .ns_per_op}]' \
            target/bench-report-fixed.json > bench-output-fixed.json

      # ── Market-state benchmarks (Criterion) ──
      - name: Clear Criterion cache before market-state bench
        run: rm -rf target/criterion
      - name: Run market-state benchmarks
        run: cargo +nightly bench --bench market_state
        env:
          RUSTFLAGS: "-C target-cpu=native"
      - name: Convert market-state Criterion results to JSON report
        run: bash .github/scripts/criterion-to-json.sh market_state
      - name: Convert market-state report for CI tracking
        run: |
          jq '[.results[] | {name: ("market_state/" + .workload), unit: "ns/op", value: .ns_per_op}]' \
            target/bench-report-market_state.json > bench-output-market_state.json
      - name: Merge benchmark outputs
        run: |
          jq -s 'add' bench-output-seqlock.json bench-output-fixed.json bench-output-market_state.json > bench-output.json
      - name: Restore Cargo.lock before gh-pages switch
        run: git checkout -- Cargo.lock
      - name: Store benchmark result
        uses: benchmark-action/github-action-benchmark@a7bc2366eda11037936ea57d811a43b3418d3073 # v1.21.0
        with:
          name: Mantis Benchmarks (${{ matrix.os }})
          tool: customSmallerIsBetter
          output-file-path: bench-output.json
          github-token: ${{ secrets.GITHUB_TOKEN }}
          auto-push: false
          alert-threshold: "105%"
          comment-on-alert: true
          fail-on-alert: true
          alert-comment-cc-users: "@mantis-maintainers"
      - name: Upload benchmark results
        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
        with:
          name: benchmark-results-${{ matrix.os }}
          path: |
            target/bench-report-seqlock.json
            target/bench-report-fixed.json
            target/bench-report-market_state.json
            bench-output.json

  report:
    name: Post benchmark report
    needs: benchmark
    if: always() && github.event_name == 'pull_request'
    runs-on: ubuntu-latest
    permissions:
      pull-requests: write
    steps:
      - name: Checkout PR
        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
        with:
          persist-credentials: false
      - name: Download Linux results
        uses: actions/download-artifact@95815c38cf2ff2164869cbab79da8d1f422bc89e # v4
        with:
          name: benchmark-results-ubuntu-latest
          path: results/linux
        continue-on-error: true
      - name: Download macOS results
        uses: actions/download-artifact@95815c38cf2ff2164869cbab79da8d1f422bc89e # v4
        with:
          name: benchmark-results-macos-latest
          path: results/macos
        continue-on-error: true
      - name: Generate markdown report
        run: |
          linux_seqlock="results/linux/target/bench-report-seqlock.json"
          macos_seqlock="results/macos/target/bench-report-seqlock.json"
          linux_fixed="results/linux/target/bench-report-fixed.json"
          macos_fixed="results/macos/target/bench-report-fixed.json"
          linux_market_state="results/linux/target/bench-report-market_state.json"
          macos_market_state="results/macos/target/bench-report-market_state.json"
          bash .github/scripts/bench-report.sh \
            "$linux_seqlock" "$macos_seqlock" \
            "$linux_fixed" "$macos_fixed" \
            "$linux_market_state" "$macos_market_state" > report.md
      - name: Post PR comment
        uses: marocchino/sticky-pull-request-comment@52423e01640425a022ef5fd42c6fb5f633a02728 # v2.9.1
        with:
          header: benchmark-report
          path: report.md