CPU sample data collected using collectCpuSamples() from Blazor WebAssembly app doesn't load in Visual Studio

[danroth27]

Repro steps:

• Install .NET 10 Preview 4 with the wasm-tools workload
• dotnet new blazor -int WebAssembly -o BlazorApp
• Edit BlazorApp.Client.csproj to add the following MSBuild properties:

<WasmPerfTracing>true</WasmPerfTracing>
<WasmPerfInstrumentation>all</WasmPerfInstrumentation>
<EventSourceSupport>true</EventSourceSupport>
<MetricsSupport>true</MetricsSupport>

• cd BlazorApp/BlazorApp
• dotnet run
• Browse to the Counter page
• In the browser dev console run globalThis.getDotnetRuntime(0).collectCpuSamples({durationSeconds: 5}); and then click the Counter button repeatedly to generate some runtime data.
• Open the downloaded .nettrace file in VS

Expected result: CPU data shows up in the CPU Usage tab in VS
Actual result: The CPU Usage tab displays "There is no data available to show."

trace.1747249966275.zip

[dotnet-policy-service]

Tagging subscribers to 'arch-wasm': @lewing
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[pavelsavara]

@hakenr noticed that you can get No active JS diagnostic session and that adding <WasmBuildNative>true</WasmBuildNative> helps.