[wasm] Blazor apps started from Visual Studio have optimizations disabled, even in Release

[BrzVlad]

Steps to reproduce:

• Create blazor wasm template
• Add some code that requires optimizations. For example, on counter page

@page "/counter"
@using System.Diagnostics

<h1>Counter</h1>

<p>Current count: @currentCount</p>

<button class="btn btn-primary" @onclick="IncrementCount">Click me</button>

@code {
    private int currentCount = 0;
    private int result;

    private int Add (int a, int b)
    {
        return a + b;
    }

    private void TestMethod ()
    {
        for (int i = 0; i < 100000; i++) {
            int a = 10;
            int b = 20;
            result += Add (a, b);
        }

    }

    private void IncrementCount ()
    {
        Stopwatch sw = new Stopwatch ();
        sw.Start ();
        TestMethod ();
        sw.Stop ();
        Console.WriteLine ("TestMethod took {0} ms", sw.ElapsedMilliseconds);

        currentCount++;
    }
}

• Notice that, when running from visual studio the release configuration with Start without debugging, the computation time when doing a click is around 4-5 times slower than the same operation with the web app published and deployed to an IIS instance

When initializing the runtime, mono_wasm_load_runtime always receives enable_debugging as -1 when started from visual studio, while the published version has it set to 0.

[Dotnet-GitSync-Bot]

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[BrzVlad]

cc @lewing @marek-safar

[lewing]

I see the issue, fix incoming.

[ghost]

Tagging subscribers to this area: @CoffeeFlux
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[lewing]

@BrzVlad when you are running the release build are you choosing "run-without-debugging"?

[BrzVlad]

As mentioned in the description, I go to Debug menu and click Start without debugging

[lewing]

closed in favor of dotnet/aspnetcore#24623

[captainsafia]

@BrzVlad Thanks for reporting this issue.

Notice that, when running from visual studio the release configuration with Start without debugging, the computation time when doing a click is around 4-5 times slower than the same operation with the web app published and deployed to an IIS instance

I ran some tests with our perf benchmarking tool to verify the behavior here.

Here's a screenshot of perf stats on a Blazor app built with a Debug configuration.

And here's a screenshot of perf stats when running in a Release configuration.

There's not a major perf distinction between the two for the scenarios measured.

the computation time when doing a click is around 4-5 times slower than the same operation with the web app published and deployed to an IIS instance

This is expected since published apps run with debugging disabled.