Development Guidelines

This guide explains how to add a new benchmark to the CTBenchmarks.jl pipeline.

Overview

Adding a new benchmark involves creating several components:

Step-by-Step Guide

1. Create the Benchmark Script {#benchmark-script}

Create a new Julia script in the benchmarks/ directory. Choose a descriptive filename that will serve as your benchmark identifier.

Naming convention: Use kebab-case (e.g., core-ubuntu-latest.jl, core-moonshot-gpu.jl)

Example: benchmarks/core-ubuntu-latest.jl

# Benchmark script for <id>
# Setup (Pkg.activate, instantiate, update, using CTBenchmarks) is handled by the workflow

function run()
    results = CTBenchmarks.benchmark(;
        problems = [:problem1, :problem2, ...],
        solver_models = [:solver => [:model1, :model2]],
        grid_sizes = [100, 500, 1000],
        disc_methods = [:trapeze],
        tol = 1e-6,
        ipopt_mu_strategy = "adaptive",
        print_trace = false,
        max_iter = 1000,
        max_wall_time = 500.0
    )
    println("✅ Benchmark completed successfully!")
    return results
end

Key points:

• Setup code is handled by the workflow - No need to include using Pkg, Pkg.activate(), Pkg.instantiate(), Pkg.update(), or using CTBenchmarks in your script. The GitHub Actions workflow handles all environment setup automatically.
• All parameters are required - the benchmark function has no optional arguments
• Define a run() function - it must take no arguments, return the Dict payload from CTBenchmarks.benchmark, and should not perform any file I/O
• The workflow calls run(), saves the returned payload as {id}.json, and stores it under docs/src/assets/benchmarks/{id}/
• TOML files are copied by the workflow - Project.toml and Manifest.toml are automatically copied to the output directory by the GitHub Actions workflow to ensure reproducibility
• Available problems: The list of problems you can choose is available in the OptimalControlProblems.jl documentation
• For local testing: See benchmarks/local.jl for an example that includes the setup code needed to run benchmarks locally

2. Add Configuration to JSON {#json-config}

Edit benchmarks/benchmarks-config.json and add your benchmark configuration:

{
  "benchmarks": [
    {
      "id": "your-benchmark-id",
      "julia_version": "1.11",
      "julia_arch": "x64",
      "runs_on": "ubuntu-latest",
      "runner": "github"
    }
  ]
}

Configuration fields:

• id (required): Unique identifier for the benchmark (kebab-case)

  • Must exactly match your script filename (without the .jl extension)
  • Convention: {family}-{runner} (e.g., core-ubuntu-latest, core-moonshot)
  • Example: if your script is benchmarks/core-ubuntu-latest.jl, use "id": "core-ubuntu-latest"
  • Used in label: run bench {id}

• julia_version (required): Julia version to use (e.g., "1.11")

• julia_arch (required): Architecture (typically "x64")

• runs_on (required): GitHub runner specification

  • For standard runners: "ubuntu-latest"
  • For self-hosted runners with custom labels: "[\"moonshot\"]" or "[\"mothra\"]" (use the runner label configured in your self-hosted runner)`

• runner (required): Runner type for caching strategy

  • "github" for standard GitHub runners (uses julia-actions/cache)
  • "self-hosted" for self-hosted runners (uses actions/cache for artifacts only)

Examples:

// Standard GitHub runner
{
  "id": "core-ubuntu-latest",
  "julia_version": "1.11",
  "julia_arch": "x64",
  "runs_on": "ubuntu-latest",
  "runner": "github"
}

// Self-hosted runner with custom label
{
  "id": "core-moonshot",
  "julia_version": "1.11",
  "julia_arch": "x64",
  "runs_on": "[\"moonshot\"]",
  "runner": "self-hosted"
}

Conceptually, each JSON entry is mapped directly to the inputs of the reusable workflow:

benchmarks-config.json
   └─ for each {id, julia_version, julia_arch, runs_on, runner}
        └─ orchestrator matrix entry
             └─ benchmark-reusable.yml inputs:
                  script_path  = benchmarks/{id}.jl
                  julia_version
                  julia_arch
                  runs_on
                  runner

Automatic Workflow Execution

Good news! You don't need to create a workflow file manually. The orchestrator automatically runs your benchmark based on the JSON configuration using a matrix strategy.

When you add a label to a PR (e.g., run bench your-benchmark-id), the orchestrator:

1. Reads benchmarks/benchmarks-config.json
2. Finds your benchmark configuration by matching the label with the id field
3. Calls the reusable workflow with the parameters from the JSON (Julia version, architecture, runner, etc.)
4. The reusable workflow loads and executes your script at benchmarks/{id}.jl
5. Results are saved to docs/src/assets/benchmarks/{id}/{id}.json

Everything is automatic! ✨

The full CI/data flow is:

GitHub label on PR: "run bench {id}" or "run bench {prefix}-all"
   └─ Orchestrator workflow (benchmarks-orchestrator.yml)
        ├─ Guard job:
        │    ├─ read benchmarks/benchmarks-config.json
        │    └─ build JSON matrix of selected benchmarks
        ├─ Benchmark job (matrix over selected benchmarks)
        │    └─ calls benchmark-reusable.yml with
        │         script_path = benchmarks/{id}.jl
        │         julia_version, julia_arch, runs_on, runner
        │         └─ run Julia script → run() → results Dict
        │              └─ save {id}.json + TOML + script under docs/src/assets/benchmarks/{id}/
        └─ Docs job
             └─ include("docs/make.jl")
                  └─ build & deploy docs using latest JSON results

3. Create the GitHub Label {#github-label}

On GitHub, create a new label for your benchmark:

1. Go to your repository → Issues → Labels
2. Click New label
3. Name: run bench {id} where {id} matches your JSON configuration
   • Example: run bench core-ubuntu-latest
   • Example: run bench core-moonshot-gpu
   • Important: Use the exact benchmark ID from JSON
4. Choose a color and description
5. Click Create label

Label types:

1. Individual labels - Trigger a specific benchmark:

   • Format: run bench {id}
   • Example: run bench core-moonshot-gpu
   • Example: run bench minimal-ubuntu-latest

2. Group labels - Trigger all benchmarks with a common prefix:

   • Format: run bench {prefix}-all
   • Example: run bench core-all → runs all core-* benchmarks
   • Example: run bench minimal-all → runs all minimal-* benchmarks
   • Example: run bench gpu-all → runs all gpu-* benchmarks

Naming convention for benchmark families:

To use group labels effectively, follow this naming convention:

• {family}-{runner} format (e.g., core-ubuntu-latest, core-moonshot)
• All benchmarks in the same family share the same prefix
• Group label run bench {family}-all will run all benchmarks in that family

Examples:

• core-ubuntu-latest, core-moonshot-gpu, core-mothra-gpu → run bench core-all
• minimal-ubuntu-latest, minimal-moonshot-gpu, minimal-mothra-gpu → run bench minimal-all
• gpu-cuda12, gpu-cuda13 → run bench gpu-all

4. (Optional) Create Individual Workflow {#individual-workflow}

Create .github/workflows/benchmark-{id}.yml:

name: Benchmark {Name}

on:
  workflow_call:
  workflow_dispatch:

permissions:
  contents: write
  pull-requests: write

jobs:
  load-config:
    runs-on: ubuntu-latest
    outputs:
      config: ${{ steps.get-config.outputs.config }}
    steps:
      - uses: actions/checkout@v5
      - name: Get benchmark config
        id: get-config
        run: |
          CONFIG=$(jq -c '.benchmarks[] | select(.id == "{id}")' benchmarks/benchmarks-config.json)
          echo "config=$CONFIG" >> $GITHUB_OUTPUT
  
  bench:
    needs: load-config
    uses: ./.github/workflows/benchmark-reusable.yml
    with:
      script_path: benchmarks/${{ fromJSON(needs.load-config.outputs.config).id }}.jl
      julia_version: ${{ fromJSON(needs.load-config.outputs.config).julia_version }}
      julia_arch: ${{ fromJSON(needs.load-config.outputs.config).julia_arch }}
      runs_on: ${{ fromJSON(needs.load-config.outputs.config).runs_on }}
      runner: ${{ fromJSON(needs.load-config.outputs.config).runner }}

Key features:

• Reads configuration from JSON - Single source of truth
• Uses ID to construct script path - benchmarks/${{ fromJSON(...).id }}.jl ensures consistency
• Can be triggered manually via workflow_dispatch for testing
• Can be called by orchestrator via workflow_call
• No hardcoded values - Everything comes from JSON configuration

5. (Optional) Create Documentation Page {#documentation-page}

If you want to display results in the documentation, you can create a template file (for example docs/src/core/cpu.md.template for a family of benchmarks, or docs/src/benchmark-<name>.md.template for a single benchmark) and let the documentation pipeline generate the final .md page.

At a high level, a benchmark documentation page:

• Defines a single @setup BENCH block that includes utils.jl.
• Uses INCLUDE_ENVIRONMENT blocks to display environment and configuration information based on the benchmark ID.
• Uses INCLUDE_FIGURE blocks to generate clickable figures (SVG + PDF).
• Uses INCLUDE_TEXT blocks to insert performance-profile summaries or tables when needed.
• Uses @example BENCH blocks with _print_benchmark_log("<id>") to show detailed results.

For a concrete template example and a full description of how these blocks are processed, see the Documentation Generation Process.

Testing Your Benchmark

1. Local testing: Run your script locally to verify it works
2. Push changes: Commit and push all files
3. Create PR: Open a pull request
4. Add label: Add the run bench <name> label to trigger the workflow
5. Monitor: Check the Actions tab to monitor execution

Troubleshooting

Cache issues on self-hosted runners:

• Ensure "runner": "self-hosted" is set in your JSON configuration
• The reusable workflow uses actions/cache for artifacts only on self-hosted runners
• Standard GitHub runners should use "runner": "github" to enable full package caching

Workflow not triggering:

• Verify the label name matches exactly: run bench {id} where {id} is from your JSON
• Check that your benchmark ID exists in benchmarks/benchmarks-config.json
• Ensure the benchmark script file exists at benchmarks/{id}.jl

Benchmark script fails:

• Check Julia version compatibility
• Verify all dependencies are available on the target runner
• Review the benchmark function parameters

Examples

Example 1: Standard GitHub Runner

A CPU benchmark running on GitHub Actions:

JSON configuration:

{
  "id": "core-ubuntu-latest",
  "julia_version": "1.11",
  "julia_arch": "x64",
  "runs_on": "\"ubuntu-latest\"",
  "runner": "github"
}

Files:

• Script: benchmarks/core-ubuntu-latest.jl
• Label: run bench core-ubuntu-latest
• Documentation: docs/src/benchmark-core.md.template

Example 2: Self-Hosted Runner (Moonshot)

A GPU benchmark on a self-hosted runner with custom label:

JSON configuration:

{
  "id": "core-moonshot-gpu",
  "julia_version": "1.11",
  "julia_arch": "x64",
  "runs_on": "[\"moonshot\"]",
  "runner": "self-hosted"
}

Files:

• Script: benchmarks/core-moonshot-gpu.jl
• Label: run bench core-moonshot-gpu

Key points:

• Uses simplified runner label ["moonshot"] instead of full system labels
• The runner: "self-hosted" field tells the workflow to use artifact-only caching

Example 3: Multiple Runners, Same Hardware

You can create CPU and GPU variants for the same hardware:

CPU variant:

{
  "id": "core-moonshot-cpu",
  "julia_version": "1.11",
  "julia_arch": "x64",
  "runs_on": "[\"moonshot\"]",
  "runner": "self-hosted"
}

GPU variant:

{
  "id": "core-moonshot-gpu",
  "julia_version": "1.11",
  "julia_arch": "x64",
  "runs_on": "[\"moonshot\"]",
  "runner": "self-hosted"
}

Both use the same runner label but different benchmark scripts with different solver configurations.

How the Orchestrator Works

Matrix Strategy

The orchestrator uses a matrix strategy to dynamically call benchmarks:

1. Guard job reads benchmarks/benchmarks-config.json
2. Based on PR labels, it builds a JSON array of selected benchmarks
3. Benchmark job uses matrix to iterate over selected benchmarks
4. Each matrix iteration calls benchmark-reusable.yml with the appropriate parameters

Benefits:

• No need to declare individual jobs for each benchmark
• Adding a benchmark requires only JSON modification
• All benchmarks run in parallel (matrix strategy)
• Consistent behavior across all benchmarks

Label System

The orchestrator supports two types of labels with automatic prefix detection:

Individual Labels

• Format: run bench {id}
• Behavior: Runs the specific benchmark with that exact ID
• Examples:
  • run bench core-ubuntu-latest → runs only core-ubuntu-latest
  • run bench minimal-macos → runs only minimal-macos

Group Labels (Generic)

• Format: run bench {prefix}-all
• Behavior: Automatically runs all benchmarks whose ID starts with {prefix}-
• How it works:
  1. The orchestrator extracts the prefix from the label (e.g., core from run bench core-all)
  2. It scans all benchmark IDs in the JSON
  3. It selects all benchmarks matching the pattern {prefix}-*
• Examples:
  • run bench core-all → runs core-ubuntu-latest, core-moonshot-cpu, core-moonshot-gpu, core-mothra-gpu
  • run bench minimal-all → runs all benchmarks starting with minimal-

Multiple Labels

You can combine multiple labels on a PR:

• run bench core-all + run bench minimal-ubuntu-latest → runs all core-* benchmarks + minimal-ubuntu-latest
• run bench core-moonshot + run bench gpu-all → runs core-moonshot + all gpu-* benchmarks

Automatic Discovery

The system is completely generic - no hardcoded family names:

• Add benchmarks with any prefix (e.g., perf-*, stress-*, validation-*)
• Create corresponding group labels (e.g., run bench perf-all)
• The orchestrator automatically detects and processes them

Configuration File

The benchmarks/benchmarks-config.json file is the single source of truth:

• Orchestrator reads it to discover available benchmarks
• Individual workflows read it to get their configuration
• Easy to maintain and validate
• Can be extended with additional metadata