Dotnet Ci Benchmarking

Cross-references: [skill:dotnet-benchmarkdotnet] for benchmark class setup and JSON exporter configuration, [skill:dotnet-observability] for correlating benchmark regressions with runtime metrics changes, [skill:dotnet-gha-patterns] for composable workflow patterns (reusable workflows, composite actions, matrix builds).

Baseline File Management

BenchmarkDotNet JSON Export

BenchmarkDotNet's JSON exporter produces machine-readable results for automated comparison. Configure the exporter in benchmark classes:

using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Exporters.Json;

[JsonExporterAttribute.Full]
[MemoryDiagnoser]
public class CriticalPathBenchmarks
{
    [Benchmark(Baseline = true)]
    public void ProcessOrder() { /* ... */ }

    [Benchmark]
    public void ProcessOrderOptimized() { /* ... */ }
}

```text

Or configure via custom config for all benchmark classes:

```csharp

using BenchmarkDotNet.Configs;
using BenchmarkDotNet.Exporters.Json;
using BenchmarkDotNet.Jobs;
using BenchmarkDotNet.Running;

var config = ManualConfig.Create(DefaultConfig.Instance)
    .AddJob(Job.ShortRun)  // fewer iterations for CI speed
    .AddExporter(JsonExporter.Full)
    .WithArtifactsPath("./benchmark-results");

BenchmarkSwitcher.FromAssembly(typeof(Program).Assembly).Run(args, config);

```json

### JSON Export Structure

The exported JSON file (`*-report-full.json`) contains structured benchmark results:

```json

{
  "Title": "CriticalPathBenchmarks",
  "Benchmarks": [
    {
      "FullName": "MyApp.Benchmarks.CriticalPathBenchmarks.ProcessOrder",
      "Statistics": {
        "Mean": 1234.5678,
        "Median": 1230.1234,
        "StandardDeviation": 15.234,
        "StandardError": 4.812
      },
      "Memory": {
        "BytesAllocatedPerOperation": 1024,
        "Gen0Collections": 0.0012,
        "Gen1Collections": 0,
        "Gen2Collections": 0
      }
    }
  ]
}

```text

Key fields for regression comparison:

| Field                               | Purpose                                         |
| ----------------------------------- | ----------------------------------------------- |
| `Statistics.Mean`                   | Average execution time (nanoseconds)            |
| `Statistics.Median`                 | Middle execution time (more robust to outliers) |
| `Statistics.StandardDeviation`      | Measurement variability                         |
| `Memory.BytesAllocatedPerOperation` | GC allocation per operation                     |

### Baseline Storage Strategies

| Strategy                         | Pros                                   | Cons                                                            | Best For                                |
| -------------------------------- | -------------------------------------- | --------------------------------------------------------------- | --------------------------------------- |
| Git-committed baseline file      | Versioned, auditable, no external deps | Repo size grows; must update deliberately                       | Small benchmark suites, stable hardware |
| GitHub Actions artifacts         | No repo bloat; automatic retention     | 90-day default retention; cross-workflow access requires tokens | Large benchmark suites, shared runners  |
| External storage (S3/Azure Blob) | Unlimited history; cross-repo sharing  | Extra infrastructure; credential management                     | Multi-repo benchmark comparison         |

This skill focuses on the **GitHub Actions artifact** strategy as the default. For composable workflow patterns and
reusable actions, see [skill:dotnet-gha-patterns].

---

## GitHub Actions Benchmark Workflow

### Basic Benchmark Workflow

```yaml