benchmark_cpp.yml

# Copyright(C) 2025-2026 Advanced Micro Devices, Inc. All rights reserved.
# SPDX-License-Identifier: MIT

# C++ performance benchmark workflow.
# Measures binary size, startup time, loop latency, and memory footprint.
# Called from build_cpp.yml after the build job passes.

name: C++ Benchmarks

on:
  workflow_call:

permissions:
  contents: read

jobs:
  benchmark:
    name: C++ Benchmarks (${{ matrix.os }})
    runs-on: ${{ matrix.os }}
    timeout-minutes: 15

    strategy:
      fail-fast: false
      matrix:
        os: [ubuntu-latest, windows-latest]

    steps:
      - uses: actions/checkout@v6

      - name: Install OpenSSL (Linux)
        if: runner.os == 'Linux'
        run: sudo apt-get install -y libssl-dev

      - name: Install OpenSSL (Windows)
        if: runner.os == 'Windows'
        run: choco install openssl --no-progress -y

      - name: Restore FetchContent cache
        uses: actions/cache@v4
        with:
          path: cpp/build-bench/_deps
          key: fetchcontent-bench-${{ matrix.os }}-${{ hashFiles('cpp/CMakeLists.txt') }}

      # Restore baseline from last main-branch run (prefix match gets latest)
      - name: Restore benchmark baseline
        id: restore-baseline
        uses: actions/cache/restore@v4
        with:
          path: cpp/benchmark-results.json
          key: benchmark-baseline-${{ matrix.os }}-dummy
          restore-keys: benchmark-baseline-${{ matrix.os }}-

      # Rename restored results to baseline path so the compare step can find it
      - name: Rename restored cache to baseline
        shell: bash
        run: |
          if [ -f cpp/benchmark-results.json ]; then
            mv cpp/benchmark-results.json cpp/benchmark-baseline.json
          fi

      # Build static library + examples + benchmarks
      - name: Configure CMake (static + benchmarks)
        run: >
          cmake -B cpp/build-bench -S cpp
          -DCMAKE_BUILD_TYPE=Release
          -DGAIA_BUILD_BENCHMARKS=ON
          -DGAIA_BUILD_EXAMPLES=ON
          -DGAIA_BUILD_TESTS=OFF
          -DGAIA_BUILD_INTEGRATION_TESTS=OFF

      - name: Build (static + benchmarks)
        run: cmake --build cpp/build-bench --config Release --parallel

      # Build shared library separately for DLL/SO size measurement
      - name: Configure CMake (shared library)
        run: >
          cmake -B cpp/build-bench-shared -S cpp
          -DCMAKE_BUILD_TYPE=Release
          -DBUILD_SHARED_LIBS=ON
          -DGAIA_BUILD_TESTS=OFF
          -DGAIA_BUILD_EXAMPLES=OFF
          -DGAIA_BUILD_BENCHMARKS=OFF

      - name: Build (shared library)
        run: cmake --build cpp/build-bench-shared --config Release --parallel

      # Measure sizes and run all benchmarks on Linux
      - name: Run benchmarks (Linux)
        if: runner.os == 'Linux'
        run: |
          STATIC=$(stat -c%s cpp/build-bench/libgaia_core.a)
          SHARED=$(stat -c%s cpp/build-bench-shared/libgaia_core.so)
          EXE=$(stat -c%s cpp/build-bench/security_demo)
          echo "Static lib:  $STATIC bytes"
          echo "Shared lib:  $SHARED bytes"
          echo "Example exe: $EXE bytes"
          cpp/build-bench/gaia_benchmarks \
            --output cpp/benchmark-results.json \
            --static-lib-size "$STATIC" \
            --shared-lib-size "$SHARED" \
            --exe-size "$EXE"

      # Measure sizes and run all benchmarks on Windows
      - name: Run benchmarks (Windows)
        if: runner.os == 'Windows'
        shell: powershell
        run: |
          $static = (Get-Item "cpp/build-bench/Release/gaia_core.lib").Length
          $shared = (Get-Item "cpp/build-bench-shared/Release/gaia_core.dll").Length
          $exe    = (Get-Item "cpp/build-bench/Release/security_demo.exe").Length
          Write-Host "Static lib:  $static bytes"
          Write-Host "Shared lib:  $shared bytes"
          Write-Host "Example exe: $exe bytes"
          & "cpp/build-bench/Release/gaia_benchmarks.exe" `
            --output "cpp/benchmark-results.json" `
            --static-lib-size $static `
            --shared-lib-size $shared `
            --exe-size $exe

      # Compare current results against baseline (binary: 10%, others: 15%)
      - name: Compare against baseline
        shell: bash
        run: |
          if [ -f cpp/benchmark-baseline.json ]; then
            echo "Baseline found — running regression check"
            if [ "$RUNNER_OS" = "Windows" ]; then
              BENCH_EXE="cpp/build-bench/Release/gaia_benchmarks.exe"
            else
              BENCH_EXE="cpp/build-bench/gaia_benchmarks"
            fi
            "$BENCH_EXE" \
              --compare \
              --baseline cpp/benchmark-baseline.json \
              --current  cpp/benchmark-results.json
          else
            echo "No baseline found — first run establishes the baseline"
          fi

      # Save new baseline only on pushes to main (immutable cache: unique key per run)
      - name: Save benchmark baseline
        if: github.ref == 'refs/heads/main' && github.event_name == 'push'
        uses: actions/cache/save@v4
        with:
          path: cpp/benchmark-results.json
          key: benchmark-baseline-${{ matrix.os }}-${{ github.run_id }}

      # Always upload results as an artifact for inspection
      - name: Upload benchmark results
        uses: actions/upload-artifact@v6
        if: always()
        with:
          name: cpp-benchmark-${{ matrix.os }}
          path: cpp/benchmark-results.json