Benchmarks workflow (webpack/webpack)

The Benchmarks workflow from webpack/webpack, explained and optimized by Latchkey.

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Source: webpack/webpack.github/workflows/benchmarks.ymlLicense MITView source

What it does

This is the Benchmarks workflow from the webpack/webpack repository, a real project running GitHub Actions. It is shown here with attribution under its MIT license.

Below, Latchkey shows a faster, safer version produced by its optimization engine.

The workflow

workflow (.yml)

name: Benchmarks

on:
  push:
    branches: [main]
  pull_request:
    branches: [main]
  workflow_dispatch:

concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true

permissions:
  contents: read
  id-token: write # Required for OIDC authentication with CodSpeed

jobs:
  benchmark:
    strategy:
      fail-fast: false
      matrix:
        shard: [1/4, 2/4, 3/4, 4/4]
    runs-on: ubuntu-latest
    permissions:
      issues: write
      pull-requests: write
    steps:
      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
        with:
          fetch-tags: true
          fetch-depth: 0

      - name: Use Node.js
        uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6.4.0
        with:
          node-version: lts/*
          cache: yarn

      - run: yarn --frozen-lockfile

      - run: yarn link --frozen-lockfile || true

      - run: yarn link webpack --frozen-lockfile

      - name: Check Memory Status
        run: >
          node -e 'const os=require("os");
          const toGb=b=>(b/1024**3).toFixed(2)+" GB";
          console.log(`--- Memory Status ---\nTotal: ${toGb(os.totalmem())}\nFree:  ${toGb(os.freemem())}\nUsed:  ${toGb(os.totalmem()-os.freemem())}`)'

      - name: Run benchmarks
        uses: CodSpeedHQ/action@4e969336ab9acd4f6f8d025fdd793292b0835df0 # v4.18.2
        with:
          run: yarn benchmark --ci
          mode: "simulation"
        env:
          LAST_COMMIT: 1
          NEGATIVE_FILTER: on-schedule
          SHARD: ${{ matrix.shard }}
          # Single libuv thread → deterministic fs-completion order, removing the
          # last I/O race that perturbs allocation counts between runs.
          UV_THREADPOOL_SIZE: 1
  benchmark-memory:
    strategy:
      fail-fast: false
      matrix:
        shard: [1/4, 2/4, 3/4, 4/4]
    runs-on: ubuntu-latest
    permissions:
      issues: write
      pull-requests: write
    steps:
      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
        with:
          fetch-tags: true
          fetch-depth: 0

      - name: Use Node.js
        uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6.4.0
        with:
          node-version: lts/*
          cache: yarn

      - run: yarn --frozen-lockfile

      - run: yarn link --frozen-lockfile || true

      - run: yarn link webpack --frozen-lockfile

      - name: Check Memory Status
        run: >
          node -e 'const os=require("os");
          const toGb=b=>(b/1024**3).toFixed(2)+" GB";
          console.log(`--- Memory Status ---\nTotal: ${toGb(os.totalmem())}\nFree:  ${toGb(os.freemem())}\nUsed:  ${toGb(os.totalmem()-os.freemem())}`)'

      - name: Run memory benchmarks
        uses: CodSpeedHQ/action@4e969336ab9acd4f6f8d025fdd793292b0835df0 # v4.18.2
        with:
          run: yarn benchmark --ci
          mode: "memory"
          token: ${{ secrets.CODSPEED_TOKEN }}
        env:
          LAST_COMMIT: 1
          NEGATIVE_FILTER: on-schedule
          SHARD: ${{ matrix.shard }}
          # Single libuv thread → deterministic fs-completion order, removing the
          # last I/O race that perturbs allocation counts between runs.
          UV_THREADPOOL_SIZE: 1

The same workflow, on Latchkey

Removes redundant runs and caps runaway jobs. Added and changed lines are highlighted.

name: Benchmarks
 
on:
  push:
    branches: [main]
  pull_request:
    branches: [main]
  workflow_dispatch:
 
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
 
permissions:
  contents: read
  id-token: write # Required for OIDC authentication with CodSpeed
 
jobs:
  benchmark:
    timeout-minutes: 30
    strategy:
      fail-fast: false
      matrix:
        shard: [1/4, 2/4, 3/4, 4/4]
    runs-on: latchkey-small
    permissions:
      issues: write
      pull-requests: write
    steps:
      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
        with:
          fetch-tags: true
          fetch-depth: 0
 
      - name: Use Node.js
        uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6.4.0
        with:
          node-version: lts/*
          cache: yarn
 
      - run: yarn --frozen-lockfile
 
      - run: yarn link --frozen-lockfile || true
 
      - run: yarn link webpack --frozen-lockfile
 
      - name: Check Memory Status
        run: >
          node -e 'const os=require("os");
          const toGb=b=>(b/1024**3).toFixed(2)+" GB";
          console.log(`--- Memory Status ---\nTotal: ${toGb(os.totalmem())}\nFree:  ${toGb(os.freemem())}\nUsed:  ${toGb(os.totalmem()-os.freemem())}`)'
 
      - name: Run benchmarks
        uses: CodSpeedHQ/action@4e969336ab9acd4f6f8d025fdd793292b0835df0 # v4.18.2
        with:
          run: yarn benchmark --ci
          mode: "simulation"
        env:
          LAST_COMMIT: 1
          NEGATIVE_FILTER: on-schedule
          SHARD: ${{ matrix.shard }}
          # Single libuv thread → deterministic fs-completion order, removing the
          # last I/O race that perturbs allocation counts between runs.
          UV_THREADPOOL_SIZE: 1
  benchmark-memory:
    timeout-minutes: 30
    strategy:
      fail-fast: false
      matrix:
        shard: [1/4, 2/4, 3/4, 4/4]
    runs-on: latchkey-small
    permissions:
      issues: write
      pull-requests: write
    steps:
      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
        with:
          fetch-tags: true
          fetch-depth: 0
 
      - name: Use Node.js
        uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6.4.0
        with:
          node-version: lts/*
          cache: yarn
 
      - run: yarn --frozen-lockfile
 
      - run: yarn link --frozen-lockfile || true
 
      - run: yarn link webpack --frozen-lockfile
 
      - name: Check Memory Status
        run: >
          node -e 'const os=require("os");
          const toGb=b=>(b/1024**3).toFixed(2)+" GB";
          console.log(`--- Memory Status ---\nTotal: ${toGb(os.totalmem())}\nFree:  ${toGb(os.freemem())}\nUsed:  ${toGb(os.totalmem()-os.freemem())}`)'
 
      - name: Run memory benchmarks
        uses: CodSpeedHQ/action@4e969336ab9acd4f6f8d025fdd793292b0835df0 # v4.18.2
        with:
          run: yarn benchmark --ci
          mode: "memory"
          token: ${{ secrets.CODSPEED_TOKEN }}
        env:
          LAST_COMMIT: 1
          NEGATIVE_FILTER: on-schedule
          SHARD: ${{ matrix.shard }}
          # Single libuv thread → deterministic fs-completion order, removing the
          # last I/O race that perturbs allocation counts between runs.
          UV_THREADPOOL_SIZE: 1

What changed

Run on Latchkey managed runners with one line (runs-on), which apply the fixes below automatically and self-heal transient failures. This example uses latchkey-small; pick the runner size that fits the job.
Add a job timeout so a hung step cannot burn hours of runner time.

What Latchkey heals here

This workflow has steps that commonly fail on transient issues (network, registries, flaky browsers). On Latchkey managed runners they are detected, retried, and self-healed instead of failing your build:

Dependency installs

This workflow runs 2 jobs (8 with the matrix expanded) per trigger. On Latchkey the same minutes cost up to 58% less than GitHub-hosted, with zero queue time.

Actions used in this workflow

actions/checkout actions/setup-node