Benchmarking ASP.NET Core requests

[paulomorgado]

I want to benchmark ASP.NET Core requests using HttpClient to compare different request types.

Would using TestServer allow me to do this?

[adamsitnik]

Hi @paulomorgado

BDN itself has no ASP.NET integration, mostly because it was design for nano and micro benchmarks:

BenchmarkDotNet/docs/articles/guides/how-to-run.md

Line 7 in 7aa9759

There are several ways to run your benchmarks. What is important is that **BenchmarkDotNet works only with Console Apps**. It does not support any other kind of application like ASP.NET, Azure WebJobs, etc.

Personally I recommend using https://github.com/dotnet/crank which is also used by the ASP.NET Team to benchmark ASP.NET apps.

[paulomorgado]

Isn't crank just orchestration?

I'll give a try to BDN with AllowSynchronousIO = true and PreserveExecutionContext = true options and see how it goes.

[paulomorgado]

I was able to test this with custom HttpMessageHandler that goes something like:

private sealed class JsonDeserializeHandler : HttpMessageHandler
{
    protected override async Task<HttpResponseMessage> SendAsync(
        HttpRequestMessage request, CancellationToken cancellationToken)
    {
        var httpContext = new DefaultHttpContext();
        await PopulateContextAsync(httpContext, request, cancellationToken);

        var result = await JsonSerializer.DeserializeAsync(/*...*/);

        GC.KeepAlive(result);

        return new HttpResponseMessage(HttpStatusCode.OK);
    }
}

private static async Task PopulateContextAsync(
    DefaultHttpContext httpContext, HttpRequestMessage request, CancellationToken cancellationToken)
{
    httpContext.Request.Method = request.Method.Method;

    foreach (var (key, values) in request.Headers)
    {
        httpContext.Request.Headers.Append(key, new StringValues([.. values]));
    }

    if (request.Content is not null)
    {
        foreach (var (key, values) in request.Content.Headers)
        {
            httpContext.Request.Headers.Append(key, new StringValues([.. values]));
        }

        httpContext.Request.ContentType = request.Content.Headers.ContentType?.ToString();
        httpContext.Request.ContentLength = request.Content.Headers.ContentLength;
        httpContext.Request.Body = await request.Content.ReadAsStreamAsync(cancellationToken);
    }

    // Keep multipart file buffering in memory to avoid disk I/O variance in benchmarks.
    httpContext.Features.Set<IFormFeature>(
        new FormFeature(httpContext.Request, new FormOptions
        {
            MemoryBufferThreshold = int.MaxValue
        }));
}