name: Perf (nightly)

# The performance scorecard (#221): `cargo xtask perf` on a fixed macOS runner (Apple silicon,
# Metal), every night and on demand. It never runs on pull requests, so it can't block one.
# It fails when an enforced budget in perf/budgets.toml breaks or a scenario's p50 regresses
# more than 15 % against perf/baseline.json from the same machine class (other classes are
# never compared). The table goes to the job summary; results.json is uploaded as an artifact.
#
# To give this runner class its own baseline: run it by hand with "update_baseline", download
# the `perf-baseline` artifact and commit it as perf/baseline.json in a PR.

on:
  schedule:
    - cron: "23 3 * * *"
  workflow_dispatch:
    inputs:
      quick:
        description: "Quick subset (small documents, no budgets)"
        type: boolean
        default: false
      update_baseline:
        description: "Also write perf/baseline.json from this run (uploaded as an artifact, not committed)"
        type: boolean
        default: false

permissions:
  contents: read

concurrency:
  group: perf-nightly
  cancel-in-progress: false

env:
  CARGO_TERM_COLOR: always

jobs:
  perf:
    name: perf (macOS, Apple GPU)
    # Pinned image, not -latest: the machine class must stay fixed for comparisons.
    runs-on: macos-15
    timeout-minutes: 120
    steps:
      - uses: actions/checkout@v4
        with:
          persist-credentials: false

      - uses: dtolnay/rust-toolchain@stable

      - uses: Swatinem/rust-cache@v2
        with:
          key: perf-release

      - name: Run benchmarks
        id: perf
        env:
          QUICK: ${{ inputs.quick }}
          UPDATE: ${{ inputs.update_baseline }}
        run: |
          args=()
          if [ "$QUICK" = "true" ]; then args+=(--quick); fi
          if [ "$UPDATE" = "true" ]; then args+=(--update-baseline); fi
          cargo xtask perf "${args[@]}"

      - name: Job summary
        if: always()
        run: |
          if [ -f target/perf/summary.md ]; then
            cat target/perf/summary.md >> "$GITHUB_STEP_SUMMARY"
          else
            echo "No perf summary: the run failed before writing one (see the log)." >> "$GITHUB_STEP_SUMMARY"
          fi

      - name: Upload results
        if: always()
        uses: actions/upload-artifact@v4
        with:
          name: perf-results
          path: |
            target/perf/*.json
            target/perf/summary.md
          if-no-files-found: warn
          retention-days: 30

      - name: Upload baseline
        if: always() && inputs.update_baseline
        uses: actions/upload-artifact@v4
        with:
          name: perf-baseline
          path: perf/baseline.json
          if-no-files-found: warn
          retention-days: 30