Add configurable EventPipe CPU sampling rate via DOTNET_EventPipeThreadSamplingRate - #127292

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pavelsavara merged 12 commits into
dotnet:mainfrom
pavelsavara:browser_EP_sample_rate
Apr 29, 2026
Merged

Add configurable EventPipe CPU sampling rate via DOTNET_EventPipeThreadSamplingRate#127292
pavelsavara merged 12 commits into
dotnet:mainfrom
pavelsavara:browser_EP_sample_rate

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Summary

This change introduces a new DOTNET_EventPipeThreadSamplingRate environment variable that allows overriding the default EventPipe CPU sample profiler interval.

The default 1ms is too quick for WASM/browser.

This split from #126324 for smaller code review.

Changes

New config: DOTNET_EventPipeThreadSamplingRate

  • src/coreclr/inc/clrconfigvalues.h — Register the new INTERNAL_EventPipeThreadSamplingRate DWORD config (default 0).
  • src/native/eventpipe/ep-rt.h — Declare ep_rt_config_value_get_sampling_rate() in the shared EventPipe runtime abstraction header.
  • src/native/eventpipe/ep.c — In ep_init(), read the configured rate and convert from milliseconds to nanoseconds. Falls back to the per-platform default when the value is 0.

Per-runtime implementations of ep_rt_config_value_get_sampling_rate

  • src/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.h — CoreCLR: reads via CLRConfig::GetConfigValue.
  • src/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.h — NativeAOT: reads via RhConfig::Environment::TryGetIntegerValue.
  • src/mono/mono/eventpipe/ep-rt-mono.h — Mono: reads via g_getenv("DOTNET_EventPipeThreadSamplingRate").

Blazor/Browser WASM build integration

  • src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
    • Gate _AddWasmDiagnosticPortsEnvironmentVariable target on EnableDiagnostics=true.
    • Parse WasmPerformanceInstrumentation to extract an optional ,interval=<ms> suffix.
    • Pass the filter portion as DOTNET_WasmPerformanceInstrumentation and the interval (if present) as DOTNET_EventPipeThreadSamplingRate.

Miscellaneous fixes

  • src/native/eventpipe/ds-ipc-pal-websocket.h

    • Wrap websocket extern declarations in extern "C" to prevent C++ name mangling (needed for JS interop in browser WASM).
    • Fix ds_rt_websocket_recv signature: remove incorrect const from the receive buffer parameter.

  • src/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.h

    • Add PROFILING_SUPPORTED preprocessor guard around ep_rt_notify_profiler_provider_created body.
    • Update #endif comments for clarity.

  • src/native/eventpipe/ep-session.c

    • Add EP_ASSERT(session->buffer_manager != NULL) invariant check in the streaming loop shutdown path.

@pavelsavarapavelsavara added this to the 11.0.0 milestone Apr 22, 2026
@pavelsavarapavelsavara self-assigned this Apr 22, 2026
CopilotAI review requested due to automatic review settings April 22, 2026 17:55
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Pull request overview

Adds a new runtime-configurable knob (DOTNET_EventPipeCpuSamplingRate) to override EventPipe CPU sample-profiler interval (intended to allow slower sampling on WASM/browser), and wires it through CoreCLR/NativeAOT/Mono plus browser WASM build plumbing.

Changes:

  • Introduce EventPipeCpuSamplingRate config/env var and consume it in EventPipe init (ms → ns conversion, 0 = default).
  • Implement ep_rt_config_value_get_sampling_rate() for CoreCLR, NativeAOT, and Mono runtime layers.
  • Update browser WASM SDK targets to pass DOTNET_EventPipeCpuSamplingRate (and related instrumentation env vars) and adjust websocket interop declarations.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 3 comments.

Show a summary per file
FileDescription
src/native/eventpipe/ep.cReads configurable sampling interval and applies it during ep_init().
src/native/eventpipe/ep-session.cAdds an assert in the no-threads streaming loop shutdown path.
src/native/eventpipe/ep-rt.hAdds runtime abstraction API for sampling-rate config retrieval.
src/native/eventpipe/ds-ipc-pal-websocket.hAdjusts websocket externs for C++/interop and fixes recv buffer constness.
src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targetsAdds EnableDiagnostics gating and parses WasmPerformanceInstrumentation for optional interval.
src/mono/mono/eventpipe/ep-rt-mono.hMono implementation of sampling-rate config getter via env var.
src/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.hCoreCLR implementation of sampling-rate config getter; minor preprocessor cleanup.
src/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.hNativeAOT implementation of sampling-rate config getter.
src/coreclr/inc/clrconfigvalues.hRegisters new CoreCLR config knob INTERNAL_EventPipeCpuSamplingRate.

Comment threadsrc/native/eventpipe/ep-session.c Outdated
Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets Outdated
Comment threadsrc/mono/mono/eventpipe/ep-rt-mono.h
@pavelsavara
Update src/native/eventpipe/ep-session.c
6c03fdc
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
CopilotAI review requested due to automatic review settings April 22, 2026 18:31
@pavelsavara
Update src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Micros…
9a89ca5
…oft.NET.Sdk.WebAssembly.Browser.targets
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
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Pull request overview

Copilot reviewed 9 out of 9 changed files in this pull request and generated 2 comments.

Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
Comment threadsrc/mono/mono/eventpipe/ep-rt-mono.h Outdated
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Pull request overview

Copilot reviewed 10 out of 10 changed files in this pull request and generated 2 comments.

Comment threadsrc/native/eventpipe/ep.c Outdated
Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets Outdated
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LGTM!

@jkotas

jkotas commented Apr 24, 2026

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Document this in https://learn.microsoft.com/en-us/dotnet/core/diagnostics/eventpipe#trace-using-environment-variables ?

noahfalk
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Looks good to me modulo comments inline.

Comment threadsrc/coreclr/inc/clrconfigvalues.h Outdated
Comment threadsrc/coreclr/inc/clrconfigvalues.h Outdated
Comment threadsrc/coreclr/inc/clrconfigvalues.h Outdated
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Merge branch 'main' into browser_EP_sample_rate
96ab3a8
# Conflicts:
#	src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
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Pull request overview

Copilot reviewed 10 out of 10 changed files in this pull request and generated 6 comments.

Comment threadsrc/native/eventpipe/ep.c
Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
Comment threadsrc/coreclr/inc/clrconfigvalues.h
Comment threadsrc/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.h
Comment threadsrc/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.h
@pavelsavarapavelsavara changed the title Add configurable EventPipe CPU sampling rate via DOTNET_EventPipeCpuSamplingRateAdd configurable EventPipe CPU sampling rate via DOTNET_EventPipeThreadSamplingRateApr 27, 2026
@pavelsavarapavelsavara mentioned this pull request Apr 27, 2026
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Document this in https://learn.microsoft.com/en-us/dotnet/core/diagnostics/eventpipe#trace-using-environment-variables ?

dotnet/docs#53393

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, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
 blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

Skip to content
Add configurable EventPipe CPU sampling rate via DOTNET_EventPipeThreadSamplingRate - #127292
Merged
pavelsavara merged 12 commits into
dotnet:mainfrom 
pavelsavara:browser_EP_sample_rate
Apr 29, 2026
Merged
Add configurable EventPipe CPU sampling rate via DOTNET_EventPipeThreadSamplingRate#127292
pavelsavara merged 12 commits into
dotnet:mainfrom 
pavelsavara:browser_EP_sample_rate
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Apr 22, 2026•

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Summary
This change introduces a new DOTNET_EventPipeThreadSamplingRate environment variable that allows overriding the default EventPipe CPU sample profiler interval.
The default 1ms is too quick for WASM/browser.
This split from #126324 for smaller code review.
Changes
New config: DOTNET_EventPipeThreadSamplingRate
  • src/coreclr/inc/clrconfigvalues.h — Register the new INTERNAL_EventPipeThreadSamplingRate DWORD config (default 0).
  • src/native/eventpipe/ep-rt.h — Declare ep_rt_config_value_get_sampling_rate() in the shared EventPipe runtime abstraction header.
  • src/native/eventpipe/ep.c — In ep_init(), read the configured rate and convert from milliseconds to nanoseconds. Falls back to the per-platform default when the value is 0.
Per-runtime implementations of ep_rt_config_value_get_sampling_rate
  • src/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.h — CoreCLR: reads via CLRConfig::GetConfigValue.
  • src/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.h — NativeAOT: reads via RhConfig::Environment::TryGetIntegerValue.
  • src/mono/mono/eventpipe/ep-rt-mono.h — Mono: reads via g_getenv("DOTNET_EventPipeThreadSamplingRate").
Blazor/Browser WASM build integration
  • src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
    • Gate _AddWasmDiagnosticPortsEnvironmentVariable target on EnableDiagnostics=true.
    • Parse WasmPerformanceInstrumentation to extract an optional ,interval=<ms> suffix.
    • Pass the filter portion as DOTNET_WasmPerformanceInstrumentation and the interval (if present) as DOTNET_EventPipeThreadSamplingRate.
Miscellaneous fixes
  • src/native/eventpipe/ds-ipc-pal-websocket.h
    • Wrap websocket extern declarations in extern "C" to prevent C++ name mangling (needed for JS interop in browser WASM).
    • Fix ds_rt_websocket_recv signature: remove incorrect const from the receive buffer parameter.
  • src/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.h
    • Add PROFILING_SUPPORTED preprocessor guard around ep_rt_notify_profiler_provider_created body.
    • Update #endif comments for clarity.
  • src/native/eventpipe/ep-session.c
    • Add EP_ASSERT(session->buffer_manager != NULL) invariant check in the streaming loop shutdown path.
@pavelsavarapavelsavara
added this to the 11.0.0 milestone
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Pull request overview
Adds a new runtime-configurable knob (DOTNET_EventPipeCpuSamplingRate) to override EventPipe CPU sample-profiler interval (intended to allow slower sampling on WASM/browser), and wires it through CoreCLR/NativeAOT/Mono plus browser WASM build plumbing.
Changes:
  • Introduce EventPipeCpuSamplingRate config/env var and consume it in EventPipe init (ms → ns conversion, 0 = default).
  • Implement ep_rt_config_value_get_sampling_rate() for CoreCLR, NativeAOT, and Mono runtime layers.
  • Update browser WASM SDK targets to pass DOTNET_EventPipeCpuSamplingRate (and related instrumentation env vars) and adjust websocket interop declarations.
Reviewed changes
Copilot reviewed 9 out of 9 changed files in this pull request and generated 3 comments.
Show a summary per file
FileDescription
src/native/eventpipe/ep.cReads configurable sampling interval and applies it during ep_init().
src/native/eventpipe/ep-session.cAdds an assert in the no-threads streaming loop shutdown path.
src/native/eventpipe/ep-rt.hAdds runtime abstraction API for sampling-rate config retrieval.
src/native/eventpipe/ds-ipc-pal-websocket.hAdjusts websocket externs for C++/interop and fixes recv buffer constness.
src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targetsAdds EnableDiagnostics gating and parses WasmPerformanceInstrumentation for optional interval.
src/mono/mono/eventpipe/ep-rt-mono.hMono implementation of sampling-rate config getter via env var.
src/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.hCoreCLR implementation of sampling-rate config getter; minor preprocessor cleanup.
src/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.hNativeAOT implementation of sampling-rate config getter.
src/coreclr/inc/clrconfigvalues.hRegisters new CoreCLR config knob INTERNAL_EventPipeCpuSamplingRate.
Comment threadsrc/native/eventpipe/ep-session.c
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Comment threadsrc/mono/mono/eventpipe/ep-rt-mono.h
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Update src/native/eventpipe/ep-session.c
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Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
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Update src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Micros…
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…oft.NET.Sdk.WebAssembly.Browser.targets
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Copilot reviewed 9 out of 9 changed files in this pull request and generated 2 comments.
Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
Comment threadsrc/mono/mono/eventpipe/ep-rt-mono.h
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Copilot reviewed 10 out of 10 changed files in this pull request and generated 2 comments.
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LGTM!
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Document this in https://learn.microsoft.com/en-us/dotnet/core/diagnostics/eventpipe#trace-using-environment-variables ?
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Looks good to me modulo comments inline.
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Merge branch 'main' into browser_EP_sample_rate
96ab3a8
# Conflicts:
#	src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
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Pull request overview
Copilot reviewed 10 out of 10 changed files in this pull request and generated 6 comments.
Comment threadsrc/native/eventpipe/ep.c
Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
Comment threadsrc/coreclr/inc/clrconfigvalues.h
Comment threadsrc/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.h
Comment threadsrc/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.h
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changed the title
Add configurable EventPipe CPU sampling rate via DOTNET_EventPipeCpuSamplingRateAdd configurable EventPipe CPU sampling rate via DOTNET_EventPipeThreadSamplingRateApr 27, 2026
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Document this in https://learn.microsoft.com/en-us/dotnet/core/diagnostics/eventpipe#trace-using-environment-variables ?
dotnet/docs#53393

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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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Add configurable EventPipe CPU sampling rate via DOTNET_EventPipeThreadSamplingRate - #127292
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pavelsavara merged 12 commits into
dotnet:mainfrom 
pavelsavara:browser_EP_sample_rate
Apr 29, 2026
Merged
Add configurable EventPipe CPU sampling rate via DOTNET_EventPipeThreadSamplingRate#127292
pavelsavara merged 12 commits into
dotnet:mainfrom 
pavelsavara:browser_EP_sample_rate
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Summary
This change introduces a new DOTNET_EventPipeThreadSamplingRate environment variable that allows overriding the default EventPipe CPU sample profiler interval.
The default 1ms is too quick for WASM/browser.
This split from #126324 for smaller code review.
Changes
New config: DOTNET_EventPipeThreadSamplingRate
  • src/coreclr/inc/clrconfigvalues.h — Register the new INTERNAL_EventPipeThreadSamplingRate DWORD config (default 0).
  • src/native/eventpipe/ep-rt.h — Declare ep_rt_config_value_get_sampling_rate() in the shared EventPipe runtime abstraction header.
  • src/native/eventpipe/ep.c — In ep_init(), read the configured rate and convert from milliseconds to nanoseconds. Falls back to the per-platform default when the value is 0.
Per-runtime implementations of ep_rt_config_value_get_sampling_rate
  • src/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.h — CoreCLR: reads via CLRConfig::GetConfigValue.
  • src/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.h — NativeAOT: reads via RhConfig::Environment::TryGetIntegerValue.
  • src/mono/mono/eventpipe/ep-rt-mono.h — Mono: reads via g_getenv("DOTNET_EventPipeThreadSamplingRate").
Blazor/Browser WASM build integration
  • src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
    • Gate _AddWasmDiagnosticPortsEnvironmentVariable target on EnableDiagnostics=true.
    • Parse WasmPerformanceInstrumentation to extract an optional ,interval=<ms> suffix.
    • Pass the filter portion as DOTNET_WasmPerformanceInstrumentation and the interval (if present) as DOTNET_EventPipeThreadSamplingRate.
Miscellaneous fixes
  • src/native/eventpipe/ds-ipc-pal-websocket.h
    • Wrap websocket extern declarations in extern "C" to prevent C++ name mangling (needed for JS interop in browser WASM).
    • Fix ds_rt_websocket_recv signature: remove incorrect const from the receive buffer parameter.
  • src/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.h
    • Add PROFILING_SUPPORTED preprocessor guard around ep_rt_notify_profiler_provider_created body.
    • Update #endif comments for clarity.
  • src/native/eventpipe/ep-session.c
    • Add EP_ASSERT(session->buffer_manager != NULL) invariant check in the streaming loop shutdown path.
@pavelsavarapavelsavara
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Pull request overview
Adds a new runtime-configurable knob (DOTNET_EventPipeCpuSamplingRate) to override EventPipe CPU sample-profiler interval (intended to allow slower sampling on WASM/browser), and wires it through CoreCLR/NativeAOT/Mono plus browser WASM build plumbing.
Changes:
  • Introduce EventPipeCpuSamplingRate config/env var and consume it in EventPipe init (ms → ns conversion, 0 = default).
  • Implement ep_rt_config_value_get_sampling_rate() for CoreCLR, NativeAOT, and Mono runtime layers.
  • Update browser WASM SDK targets to pass DOTNET_EventPipeCpuSamplingRate (and related instrumentation env vars) and adjust websocket interop declarations.
Reviewed changes
Copilot reviewed 9 out of 9 changed files in this pull request and generated 3 comments.
Show a summary per file
FileDescription
src/native/eventpipe/ep.cReads configurable sampling interval and applies it during ep_init().
src/native/eventpipe/ep-session.cAdds an assert in the no-threads streaming loop shutdown path.
src/native/eventpipe/ep-rt.hAdds runtime abstraction API for sampling-rate config retrieval.
src/native/eventpipe/ds-ipc-pal-websocket.hAdjusts websocket externs for C++/interop and fixes recv buffer constness.
src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targetsAdds EnableDiagnostics gating and parses WasmPerformanceInstrumentation for optional interval.
src/mono/mono/eventpipe/ep-rt-mono.hMono implementation of sampling-rate config getter via env var.
src/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.hCoreCLR implementation of sampling-rate config getter; minor preprocessor cleanup.
src/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.hNativeAOT implementation of sampling-rate config getter.
src/coreclr/inc/clrconfigvalues.hRegisters new CoreCLR config knob INTERNAL_EventPipeCpuSamplingRate.
Comment threadsrc/native/eventpipe/ep-session.c
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Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
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Comment threadsrc/mono/mono/eventpipe/ep-rt-mono.h
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Update src/native/eventpipe/ep-session.c
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Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
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Update src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Micros…
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…oft.NET.Sdk.WebAssembly.Browser.targets
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Pull request overview
Copilot reviewed 9 out of 9 changed files in this pull request and generated 2 comments.
Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
Comment threadsrc/mono/mono/eventpipe/ep-rt-mono.h
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Pull request overview
Copilot reviewed 10 out of 10 changed files in this pull request and generated 2 comments.
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LGTM!
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Document this in https://learn.microsoft.com/en-us/dotnet/core/diagnostics/eventpipe#trace-using-environment-variables ?
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Looks good to me modulo comments inline.
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Merge branch 'main' into browser_EP_sample_rate
96ab3a8
# Conflicts:
#	src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
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Pull request overview
Copilot reviewed 10 out of 10 changed files in this pull request and generated 6 comments.
Comment threadsrc/native/eventpipe/ep.c
Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
Comment threadsrc/coreclr/inc/clrconfigvalues.h
Comment threadsrc/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.h
Comment threadsrc/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.h
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changed the title
Add configurable EventPipe CPU sampling rate via DOTNET_EventPipeCpuSamplingRateAdd configurable EventPipe CPU sampling rate via DOTNET_EventPipeThreadSamplingRateApr 27, 2026
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Document this in https://learn.microsoft.com/en-us/dotnet/core/diagnostics/eventpipe#trace-using-environment-variables ?
dotnet/docs#53393

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@noahfalknoahfalknoahfalk approved these changes
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
Add configurable EventPipe CPU sampling rate via DOTNET_EventPipeThreadSamplingRate - #127292
Merged
pavelsavara merged 12 commits into
dotnet:mainfrom 
pavelsavara:browser_EP_sample_rate
Apr 29, 2026
Merged
Add configurable EventPipe CPU sampling rate via DOTNET_EventPipeThreadSamplingRate#127292
pavelsavara merged 12 commits into
dotnet:mainfrom 
pavelsavara:browser_EP_sample_rate
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Summary
This change introduces a new DOTNET_EventPipeThreadSamplingRate environment variable that allows overriding the default EventPipe CPU sample profiler interval.
The default 1ms is too quick for WASM/browser.
This split from #126324 for smaller code review.
Changes
New config: DOTNET_EventPipeThreadSamplingRate
  • src/coreclr/inc/clrconfigvalues.h — Register the new INTERNAL_EventPipeThreadSamplingRate DWORD config (default 0).
  • src/native/eventpipe/ep-rt.h — Declare ep_rt_config_value_get_sampling_rate() in the shared EventPipe runtime abstraction header.
  • src/native/eventpipe/ep.c — In ep_init(), read the configured rate and convert from milliseconds to nanoseconds. Falls back to the per-platform default when the value is 0.
Per-runtime implementations of ep_rt_config_value_get_sampling_rate
  • src/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.h — CoreCLR: reads via CLRConfig::GetConfigValue.
  • src/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.h — NativeAOT: reads via RhConfig::Environment::TryGetIntegerValue.
  • src/mono/mono/eventpipe/ep-rt-mono.h — Mono: reads via g_getenv("DOTNET_EventPipeThreadSamplingRate").
Blazor/Browser WASM build integration
  • src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
    • Gate _AddWasmDiagnosticPortsEnvironmentVariable target on EnableDiagnostics=true.
    • Parse WasmPerformanceInstrumentation to extract an optional ,interval=<ms> suffix.
    • Pass the filter portion as DOTNET_WasmPerformanceInstrumentation and the interval (if present) as DOTNET_EventPipeThreadSamplingRate.
Miscellaneous fixes
  • src/native/eventpipe/ds-ipc-pal-websocket.h
    • Wrap websocket extern declarations in extern "C" to prevent C++ name mangling (needed for JS interop in browser WASM).
    • Fix ds_rt_websocket_recv signature: remove incorrect const from the receive buffer parameter.
  • src/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.h
    • Add PROFILING_SUPPORTED preprocessor guard around ep_rt_notify_profiler_provider_created body.
    • Update #endif comments for clarity.
  • src/native/eventpipe/ep-session.c
    • Add EP_ASSERT(session->buffer_manager != NULL) invariant check in the streaming loop shutdown path.
@pavelsavarapavelsavara
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Pull request overview
Adds a new runtime-configurable knob (DOTNET_EventPipeCpuSamplingRate) to override EventPipe CPU sample-profiler interval (intended to allow slower sampling on WASM/browser), and wires it through CoreCLR/NativeAOT/Mono plus browser WASM build plumbing.
Changes:
  • Introduce EventPipeCpuSamplingRate config/env var and consume it in EventPipe init (ms → ns conversion, 0 = default).
  • Implement ep_rt_config_value_get_sampling_rate() for CoreCLR, NativeAOT, and Mono runtime layers.
  • Update browser WASM SDK targets to pass DOTNET_EventPipeCpuSamplingRate (and related instrumentation env vars) and adjust websocket interop declarations.
Reviewed changes
Copilot reviewed 9 out of 9 changed files in this pull request and generated 3 comments.
Show a summary per file
FileDescription
src/native/eventpipe/ep.cReads configurable sampling interval and applies it during ep_init().
src/native/eventpipe/ep-session.cAdds an assert in the no-threads streaming loop shutdown path.
src/native/eventpipe/ep-rt.hAdds runtime abstraction API for sampling-rate config retrieval.
src/native/eventpipe/ds-ipc-pal-websocket.hAdjusts websocket externs for C++/interop and fixes recv buffer constness.
src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targetsAdds EnableDiagnostics gating and parses WasmPerformanceInstrumentation for optional interval.
src/mono/mono/eventpipe/ep-rt-mono.hMono implementation of sampling-rate config getter via env var.
src/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.hCoreCLR implementation of sampling-rate config getter; minor preprocessor cleanup.
src/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.hNativeAOT implementation of sampling-rate config getter.
src/coreclr/inc/clrconfigvalues.hRegisters new CoreCLR config knob INTERNAL_EventPipeCpuSamplingRate.
Comment threadsrc/native/eventpipe/ep-session.c
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Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
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Comment threadsrc/mono/mono/eventpipe/ep-rt-mono.h
@pavelsavara
Update src/native/eventpipe/ep-session.c
6c03fdc
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
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Update src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Micros…
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…oft.NET.Sdk.WebAssembly.Browser.targets
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
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Pull request overview
Copilot reviewed 9 out of 9 changed files in this pull request and generated 2 comments.
Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
Comment threadsrc/mono/mono/eventpipe/ep-rt-mono.h
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Pull request overview
Copilot reviewed 10 out of 10 changed files in this pull request and generated 2 comments.
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LGTM!
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Document this in https://learn.microsoft.com/en-us/dotnet/core/diagnostics/eventpipe#trace-using-environment-variables ?
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Looks good to me modulo comments inline.
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Comment threadsrc/coreclr/inc/clrconfigvalues.h
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Merge branch 'main' into browser_EP_sample_rate
96ab3a8
# Conflicts:
#	src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
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Pull request overview
Copilot reviewed 10 out of 10 changed files in this pull request and generated 6 comments.
Comment threadsrc/native/eventpipe/ep.c
Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
Comment threadsrc/coreclr/inc/clrconfigvalues.h
Comment threadsrc/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.h
Comment threadsrc/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.h
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changed the title
Add configurable EventPipe CPU sampling rate via DOTNET_EventPipeCpuSamplingRateAdd configurable EventPipe CPU sampling rate via DOTNET_EventPipeThreadSamplingRateApr 27, 2026
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Document this in https://learn.microsoft.com/en-us/dotnet/core/diagnostics/eventpipe#trace-using-environment-variables ?
dotnet/docs#53393

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@noahfalknoahfalknoahfalk approved these changes
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

Skip to content
Add configurable EventPipe CPU sampling rate via DOTNET_EventPipeThreadSamplingRate - #127292
Merged
pavelsavara merged 12 commits into
dotnet:mainfrom 
pavelsavara:browser_EP_sample_rate
Apr 29, 2026
Merged
Add configurable EventPipe CPU sampling rate via DOTNET_EventPipeThreadSamplingRate#127292
pavelsavara merged 12 commits into
dotnet:mainfrom 
pavelsavara:browser_EP_sample_rate
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Summary
This change introduces a new DOTNET_EventPipeThreadSamplingRate environment variable that allows overriding the default EventPipe CPU sample profiler interval.
The default 1ms is too quick for WASM/browser.
This split from #126324 for smaller code review.
Changes
New config: DOTNET_EventPipeThreadSamplingRate
  • src/coreclr/inc/clrconfigvalues.h — Register the new INTERNAL_EventPipeThreadSamplingRate DWORD config (default 0).
  • src/native/eventpipe/ep-rt.h — Declare ep_rt_config_value_get_sampling_rate() in the shared EventPipe runtime abstraction header.
  • src/native/eventpipe/ep.c — In ep_init(), read the configured rate and convert from milliseconds to nanoseconds. Falls back to the per-platform default when the value is 0.
Per-runtime implementations of ep_rt_config_value_get_sampling_rate
  • src/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.h — CoreCLR: reads via CLRConfig::GetConfigValue.
  • src/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.h — NativeAOT: reads via RhConfig::Environment::TryGetIntegerValue.
  • src/mono/mono/eventpipe/ep-rt-mono.h — Mono: reads via g_getenv("DOTNET_EventPipeThreadSamplingRate").
Blazor/Browser WASM build integration
  • src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
    • Gate _AddWasmDiagnosticPortsEnvironmentVariable target on EnableDiagnostics=true.
    • Parse WasmPerformanceInstrumentation to extract an optional ,interval=<ms> suffix.
    • Pass the filter portion as DOTNET_WasmPerformanceInstrumentation and the interval (if present) as DOTNET_EventPipeThreadSamplingRate.
Miscellaneous fixes
  • src/native/eventpipe/ds-ipc-pal-websocket.h
    • Wrap websocket extern declarations in extern "C" to prevent C++ name mangling (needed for JS interop in browser WASM).
    • Fix ds_rt_websocket_recv signature: remove incorrect const from the receive buffer parameter.
  • src/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.h
    • Add PROFILING_SUPPORTED preprocessor guard around ep_rt_notify_profiler_provider_created body.
    • Update #endif comments for clarity.
  • src/native/eventpipe/ep-session.c
    • Add EP_ASSERT(session->buffer_manager != NULL) invariant check in the streaming loop shutdown path.
@pavelsavarapavelsavara
added this to the 11.0.0 milestone
Apr 22, 2026
@pavelsavarapavelsavara
self-assigned this
Apr 22, 2026
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Pull request overview
Adds a new runtime-configurable knob (DOTNET_EventPipeCpuSamplingRate) to override EventPipe CPU sample-profiler interval (intended to allow slower sampling on WASM/browser), and wires it through CoreCLR/NativeAOT/Mono plus browser WASM build plumbing.
Changes:
  • Introduce EventPipeCpuSamplingRate config/env var and consume it in EventPipe init (ms → ns conversion, 0 = default).
  • Implement ep_rt_config_value_get_sampling_rate() for CoreCLR, NativeAOT, and Mono runtime layers.
  • Update browser WASM SDK targets to pass DOTNET_EventPipeCpuSamplingRate (and related instrumentation env vars) and adjust websocket interop declarations.
Reviewed changes
Copilot reviewed 9 out of 9 changed files in this pull request and generated 3 comments.
Show a summary per file
FileDescription
src/native/eventpipe/ep.cReads configurable sampling interval and applies it during ep_init().
src/native/eventpipe/ep-session.cAdds an assert in the no-threads streaming loop shutdown path.
src/native/eventpipe/ep-rt.hAdds runtime abstraction API for sampling-rate config retrieval.
src/native/eventpipe/ds-ipc-pal-websocket.hAdjusts websocket externs for C++/interop and fixes recv buffer constness.
src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targetsAdds EnableDiagnostics gating and parses WasmPerformanceInstrumentation for optional interval.
src/mono/mono/eventpipe/ep-rt-mono.hMono implementation of sampling-rate config getter via env var.
src/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.hCoreCLR implementation of sampling-rate config getter; minor preprocessor cleanup.
src/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.hNativeAOT implementation of sampling-rate config getter.
src/coreclr/inc/clrconfigvalues.hRegisters new CoreCLR config knob INTERNAL_EventPipeCpuSamplingRate.
Comment threadsrc/native/eventpipe/ep-session.c
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Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
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Comment threadsrc/mono/mono/eventpipe/ep-rt-mono.h
@pavelsavara
Update src/native/eventpipe/ep-session.c
6c03fdc
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
CopilotAI
review requested due to automatic review settings
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@pavelsavara
Update src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Micros…
9a89ca5
…oft.NET.Sdk.WebAssembly.Browser.targets
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
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Pull request overview
Copilot reviewed 9 out of 9 changed files in this pull request and generated 2 comments.
Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
Comment threadsrc/mono/mono/eventpipe/ep-rt-mono.h
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Copilot encountered an error and was unable to review this pull request. You can try again by re-requesting a review.
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Comment threadsrc/native/eventpipe/ep-session.c
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Pull request overview
Copilot reviewed 10 out of 10 changed files in this pull request and generated 2 comments.
Comment threadsrc/native/eventpipe/ep.c
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Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
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LGTM!
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Document this in https://learn.microsoft.com/en-us/dotnet/core/diagnostics/eventpipe#trace-using-environment-variables ?
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Looks good to me modulo comments inline.
Comment threadsrc/coreclr/inc/clrconfigvalues.h
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Comment threadsrc/coreclr/inc/clrconfigvalues.h
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Comment threadsrc/coreclr/inc/clrconfigvalues.h
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@pavelsavara
feedback
6e9b780
@pavelsavara
Merge branch 'main' into browser_EP_sample_rate
96ab3a8
# Conflicts:
#	src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
@pavelsavara
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Pull request overview
Copilot reviewed 10 out of 10 changed files in this pull request and generated 6 comments.
Comment threadsrc/native/eventpipe/ep.c
Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
Comment threadsrc/coreclr/inc/clrconfigvalues.h
Comment threadsrc/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.h
Comment threadsrc/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.h
@pavelsavarapavelsavara
changed the title
Add configurable EventPipe CPU sampling rate via DOTNET_EventPipeCpuSamplingRateAdd configurable EventPipe CPU sampling rate via DOTNET_EventPipeThreadSamplingRateApr 27, 2026
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mentioned this pull request
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Document this in https://learn.microsoft.com/en-us/dotnet/core/diagnostics/eventpipe#trace-using-environment-variables ?
dotnet/docs#53393

This was referenced Apr 27, 2026

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merged commit 4e8ab2d
into
dotnet:mainApr 29, 2026

158 of 160 checks passed

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deleted the

browser_EP_sample_rate

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April 29, 2026 07:15
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@noahfalknoahfalknoahfalk approved these changes
@jkotasjkotasjkotas left review comments
@marafmarafmaraf left review comments
@lateralusXlateralusXlateralusX approved these changes
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@lewinglewingAwaiting requested review from lewinglewing is a code owner
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@pavelsavara@jkotas@noahfalk@maraf@lateralusX

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
Add configurable EventPipe CPU sampling rate via DOTNET_EventPipeThreadSamplingRate - #127292
Merged
pavelsavara merged 12 commits into
dotnet:mainfrom 
pavelsavara:browser_EP_sample_rate
Apr 29, 2026
Merged
Add configurable EventPipe CPU sampling rate via DOTNET_EventPipeThreadSamplingRate#127292
pavelsavara merged 12 commits into
dotnet:mainfrom 
pavelsavara:browser_EP_sample_rate
Conversation
@pavelsavara
@pavelsavarapavelsavara
commented
Apr 22, 2026•

edited

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Summary
This change introduces a new DOTNET_EventPipeThreadSamplingRate environment variable that allows overriding the default EventPipe CPU sample profiler interval.
The default 1ms is too quick for WASM/browser.
This split from #126324 for smaller code review.
Changes
New config: DOTNET_EventPipeThreadSamplingRate
  • src/coreclr/inc/clrconfigvalues.h — Register the new INTERNAL_EventPipeThreadSamplingRate DWORD config (default 0).
  • src/native/eventpipe/ep-rt.h — Declare ep_rt_config_value_get_sampling_rate() in the shared EventPipe runtime abstraction header.
  • src/native/eventpipe/ep.c — In ep_init(), read the configured rate and convert from milliseconds to nanoseconds. Falls back to the per-platform default when the value is 0.
Per-runtime implementations of ep_rt_config_value_get_sampling_rate
  • src/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.h — CoreCLR: reads via CLRConfig::GetConfigValue.
  • src/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.h — NativeAOT: reads via RhConfig::Environment::TryGetIntegerValue.
  • src/mono/mono/eventpipe/ep-rt-mono.h — Mono: reads via g_getenv("DOTNET_EventPipeThreadSamplingRate").
Blazor/Browser WASM build integration
  • src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
    • Gate _AddWasmDiagnosticPortsEnvironmentVariable target on EnableDiagnostics=true.
    • Parse WasmPerformanceInstrumentation to extract an optional ,interval=<ms> suffix.
    • Pass the filter portion as DOTNET_WasmPerformanceInstrumentation and the interval (if present) as DOTNET_EventPipeThreadSamplingRate.
Miscellaneous fixes
  • src/native/eventpipe/ds-ipc-pal-websocket.h
    • Wrap websocket extern declarations in extern "C" to prevent C++ name mangling (needed for JS interop in browser WASM).
    • Fix ds_rt_websocket_recv signature: remove incorrect const from the receive buffer parameter.
  • src/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.h
    • Add PROFILING_SUPPORTED preprocessor guard around ep_rt_notify_profiler_provider_created body.
    • Update #endif comments for clarity.
  • src/native/eventpipe/ep-session.c
    • Add EP_ASSERT(session->buffer_manager != NULL) invariant check in the streaming loop shutdown path.
@pavelsavarapavelsavara
added this to the 11.0.0 milestone
Apr 22, 2026
@pavelsavarapavelsavara
self-assigned this
Apr 22, 2026
CopilotAI
review requested due to automatic review settings
April 22, 2026 17:55
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Tagging subscribers to this area: @steveisok, @dotnet/area-system-diagnostics

See info in area-owners.md if you want to be subscribed.
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Pull request overview
Adds a new runtime-configurable knob (DOTNET_EventPipeCpuSamplingRate) to override EventPipe CPU sample-profiler interval (intended to allow slower sampling on WASM/browser), and wires it through CoreCLR/NativeAOT/Mono plus browser WASM build plumbing.
Changes:
  • Introduce EventPipeCpuSamplingRate config/env var and consume it in EventPipe init (ms → ns conversion, 0 = default).
  • Implement ep_rt_config_value_get_sampling_rate() for CoreCLR, NativeAOT, and Mono runtime layers.
  • Update browser WASM SDK targets to pass DOTNET_EventPipeCpuSamplingRate (and related instrumentation env vars) and adjust websocket interop declarations.
Reviewed changes
Copilot reviewed 9 out of 9 changed files in this pull request and generated 3 comments.
Show a summary per file
FileDescription
src/native/eventpipe/ep.cReads configurable sampling interval and applies it during ep_init().
src/native/eventpipe/ep-session.cAdds an assert in the no-threads streaming loop shutdown path.
src/native/eventpipe/ep-rt.hAdds runtime abstraction API for sampling-rate config retrieval.
src/native/eventpipe/ds-ipc-pal-websocket.hAdjusts websocket externs for C++/interop and fixes recv buffer constness.
src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targetsAdds EnableDiagnostics gating and parses WasmPerformanceInstrumentation for optional interval.
src/mono/mono/eventpipe/ep-rt-mono.hMono implementation of sampling-rate config getter via env var.
src/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.hCoreCLR implementation of sampling-rate config getter; minor preprocessor cleanup.
src/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.hNativeAOT implementation of sampling-rate config getter.
src/coreclr/inc/clrconfigvalues.hRegisters new CoreCLR config knob INTERNAL_EventPipeCpuSamplingRate.
Comment threadsrc/native/eventpipe/ep-session.c
Outdated

Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
Outdated

Comment threadsrc/mono/mono/eventpipe/ep-rt-mono.h
@pavelsavara
Update src/native/eventpipe/ep-session.c
6c03fdc
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
CopilotAI
review requested due to automatic review settings
April 22, 2026 18:31
@pavelsavara
Update src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Micros…
9a89ca5
…oft.NET.Sdk.WebAssembly.Browser.targets
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
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Pull request overview
Copilot reviewed 9 out of 9 changed files in this pull request and generated 2 comments.
Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
Comment threadsrc/mono/mono/eventpipe/ep-rt-mono.h
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This was referenced Apr 23, 2026

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Pull request overview
Copilot reviewed 10 out of 10 changed files in this pull request and generated 2 comments.
Comment threadsrc/native/eventpipe/ep.c
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Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
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LGTM!
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Document this in https://learn.microsoft.com/en-us/dotnet/core/diagnostics/eventpipe#trace-using-environment-variables ?
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Looks good to me modulo comments inline.
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Merge branch 'main' into browser_EP_sample_rate
96ab3a8
# Conflicts:
#	src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
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Pull request overview
Copilot reviewed 10 out of 10 changed files in this pull request and generated 6 comments.
Comment threadsrc/native/eventpipe/ep.c
Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
Comment threadsrc/coreclr/inc/clrconfigvalues.h
Comment threadsrc/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.h
Comment threadsrc/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.h
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Add configurable EventPipe CPU sampling rate via DOTNET_EventPipeCpuSamplingRateAdd configurable EventPipe CPU sampling rate via DOTNET_EventPipeThreadSamplingRateApr 27, 2026
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Document this in https://learn.microsoft.com/en-us/dotnet/core/diagnostics/eventpipe#trace-using-environment-variables ?
dotnet/docs#53393

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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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Add configurable EventPipe CPU sampling rate via DOTNET_EventPipeThreadSamplingRate - #127292
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pavelsavara merged 12 commits into
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pavelsavara:browser_EP_sample_rate
Apr 29, 2026
Merged
Add configurable EventPipe CPU sampling rate via DOTNET_EventPipeThreadSamplingRate#127292
pavelsavara merged 12 commits into
dotnet:mainfrom 
pavelsavara:browser_EP_sample_rate
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Summary
This change introduces a new DOTNET_EventPipeThreadSamplingRate environment variable that allows overriding the default EventPipe CPU sample profiler interval.
The default 1ms is too quick for WASM/browser.
This split from #126324 for smaller code review.
Changes
New config: DOTNET_EventPipeThreadSamplingRate
  • src/coreclr/inc/clrconfigvalues.h — Register the new INTERNAL_EventPipeThreadSamplingRate DWORD config (default 0).
  • src/native/eventpipe/ep-rt.h — Declare ep_rt_config_value_get_sampling_rate() in the shared EventPipe runtime abstraction header.
  • src/native/eventpipe/ep.c — In ep_init(), read the configured rate and convert from milliseconds to nanoseconds. Falls back to the per-platform default when the value is 0.
Per-runtime implementations of ep_rt_config_value_get_sampling_rate
  • src/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.h — CoreCLR: reads via CLRConfig::GetConfigValue.
  • src/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.h — NativeAOT: reads via RhConfig::Environment::TryGetIntegerValue.
  • src/mono/mono/eventpipe/ep-rt-mono.h — Mono: reads via g_getenv("DOTNET_EventPipeThreadSamplingRate").
Blazor/Browser WASM build integration
  • src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
    • Gate _AddWasmDiagnosticPortsEnvironmentVariable target on EnableDiagnostics=true.
    • Parse WasmPerformanceInstrumentation to extract an optional ,interval=<ms> suffix.
    • Pass the filter portion as DOTNET_WasmPerformanceInstrumentation and the interval (if present) as DOTNET_EventPipeThreadSamplingRate.
Miscellaneous fixes
  • src/native/eventpipe/ds-ipc-pal-websocket.h
    • Wrap websocket extern declarations in extern "C" to prevent C++ name mangling (needed for JS interop in browser WASM).
    • Fix ds_rt_websocket_recv signature: remove incorrect const from the receive buffer parameter.
  • src/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.h
    • Add PROFILING_SUPPORTED preprocessor guard around ep_rt_notify_profiler_provider_created body.
    • Update #endif comments for clarity.
  • src/native/eventpipe/ep-session.c
    • Add EP_ASSERT(session->buffer_manager != NULL) invariant check in the streaming loop shutdown path.
@pavelsavarapavelsavara
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Pull request overview
Adds a new runtime-configurable knob (DOTNET_EventPipeCpuSamplingRate) to override EventPipe CPU sample-profiler interval (intended to allow slower sampling on WASM/browser), and wires it through CoreCLR/NativeAOT/Mono plus browser WASM build plumbing.
Changes:
  • Introduce EventPipeCpuSamplingRate config/env var and consume it in EventPipe init (ms → ns conversion, 0 = default).
  • Implement ep_rt_config_value_get_sampling_rate() for CoreCLR, NativeAOT, and Mono runtime layers.
  • Update browser WASM SDK targets to pass DOTNET_EventPipeCpuSamplingRate (and related instrumentation env vars) and adjust websocket interop declarations.
Reviewed changes
Copilot reviewed 9 out of 9 changed files in this pull request and generated 3 comments.
Show a summary per file
FileDescription
src/native/eventpipe/ep.cReads configurable sampling interval and applies it during ep_init().
src/native/eventpipe/ep-session.cAdds an assert in the no-threads streaming loop shutdown path.
src/native/eventpipe/ep-rt.hAdds runtime abstraction API for sampling-rate config retrieval.
src/native/eventpipe/ds-ipc-pal-websocket.hAdjusts websocket externs for C++/interop and fixes recv buffer constness.
src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targetsAdds EnableDiagnostics gating and parses WasmPerformanceInstrumentation for optional interval.
src/mono/mono/eventpipe/ep-rt-mono.hMono implementation of sampling-rate config getter via env var.
src/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.hCoreCLR implementation of sampling-rate config getter; minor preprocessor cleanup.
src/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.hNativeAOT implementation of sampling-rate config getter.
src/coreclr/inc/clrconfigvalues.hRegisters new CoreCLR config knob INTERNAL_EventPipeCpuSamplingRate.
Comment threadsrc/native/eventpipe/ep-session.c
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Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
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Comment threadsrc/mono/mono/eventpipe/ep-rt-mono.h
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Update src/native/eventpipe/ep-session.c
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Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
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Update src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Micros…
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…oft.NET.Sdk.WebAssembly.Browser.targets
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
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Pull request overview
Copilot reviewed 9 out of 9 changed files in this pull request and generated 2 comments.
Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
Comment threadsrc/mono/mono/eventpipe/ep-rt-mono.h
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Pull request overview
Copilot reviewed 10 out of 10 changed files in this pull request and generated 2 comments.
Comment threadsrc/native/eventpipe/ep.c
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Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
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LGTM!
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Document this in https://learn.microsoft.com/en-us/dotnet/core/diagnostics/eventpipe#trace-using-environment-variables ?
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Looks good to me modulo comments inline.
Comment threadsrc/coreclr/inc/clrconfigvalues.h
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Comment threadsrc/coreclr/inc/clrconfigvalues.h
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Comment threadsrc/coreclr/inc/clrconfigvalues.h
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Merge branch 'main' into browser_EP_sample_rate
96ab3a8
# Conflicts:
#	src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
@pavelsavara
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Pull request overview
Copilot reviewed 10 out of 10 changed files in this pull request and generated 6 comments.
Comment threadsrc/native/eventpipe/ep.c
Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
Comment threadsrc/coreclr/inc/clrconfigvalues.h
Comment threadsrc/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.h
Comment threadsrc/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.h
@pavelsavarapavelsavara
changed the title
Add configurable EventPipe CPU sampling rate via DOTNET_EventPipeCpuSamplingRateAdd configurable EventPipe CPU sampling rate via DOTNET_EventPipeThreadSamplingRateApr 27, 2026
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Document this in https://learn.microsoft.com/en-us/dotnet/core/diagnostics/eventpipe#trace-using-environment-variables ?
dotnet/docs#53393

This was referenced Apr 27, 2026

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@noahfalknoahfalknoahfalk approved these changes
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

Skip to content
Add configurable EventPipe CPU sampling rate via DOTNET_EventPipeThreadSamplingRate - #127292
Merged
pavelsavara merged 12 commits into
dotnet:mainfrom 
pavelsavara:browser_EP_sample_rate
Apr 29, 2026
Merged
Add configurable EventPipe CPU sampling rate via DOTNET_EventPipeThreadSamplingRate#127292
pavelsavara merged 12 commits into
dotnet:mainfrom 
pavelsavara:browser_EP_sample_rate
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Summary
This change introduces a new DOTNET_EventPipeThreadSamplingRate environment variable that allows overriding the default EventPipe CPU sample profiler interval.
The default 1ms is too quick for WASM/browser.
This split from #126324 for smaller code review.
Changes
New config: DOTNET_EventPipeThreadSamplingRate
  • src/coreclr/inc/clrconfigvalues.h — Register the new INTERNAL_EventPipeThreadSamplingRate DWORD config (default 0).
  • src/native/eventpipe/ep-rt.h — Declare ep_rt_config_value_get_sampling_rate() in the shared EventPipe runtime abstraction header.
  • src/native/eventpipe/ep.c — In ep_init(), read the configured rate and convert from milliseconds to nanoseconds. Falls back to the per-platform default when the value is 0.
Per-runtime implementations of ep_rt_config_value_get_sampling_rate
  • src/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.h — CoreCLR: reads via CLRConfig::GetConfigValue.
  • src/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.h — NativeAOT: reads via RhConfig::Environment::TryGetIntegerValue.
  • src/mono/mono/eventpipe/ep-rt-mono.h — Mono: reads via g_getenv("DOTNET_EventPipeThreadSamplingRate").
Blazor/Browser WASM build integration
  • src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
    • Gate _AddWasmDiagnosticPortsEnvironmentVariable target on EnableDiagnostics=true.
    • Parse WasmPerformanceInstrumentation to extract an optional ,interval=<ms> suffix.
    • Pass the filter portion as DOTNET_WasmPerformanceInstrumentation and the interval (if present) as DOTNET_EventPipeThreadSamplingRate.
Miscellaneous fixes
  • src/native/eventpipe/ds-ipc-pal-websocket.h
    • Wrap websocket extern declarations in extern "C" to prevent C++ name mangling (needed for JS interop in browser WASM).
    • Fix ds_rt_websocket_recv signature: remove incorrect const from the receive buffer parameter.
  • src/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.h
    • Add PROFILING_SUPPORTED preprocessor guard around ep_rt_notify_profiler_provider_created body.
    • Update #endif comments for clarity.
  • src/native/eventpipe/ep-session.c
    • Add EP_ASSERT(session->buffer_manager != NULL) invariant check in the streaming loop shutdown path.
@pavelsavarapavelsavara
added this to the 11.0.0 milestone
Apr 22, 2026
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self-assigned this
Apr 22, 2026
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Pull request overview
Adds a new runtime-configurable knob (DOTNET_EventPipeCpuSamplingRate) to override EventPipe CPU sample-profiler interval (intended to allow slower sampling on WASM/browser), and wires it through CoreCLR/NativeAOT/Mono plus browser WASM build plumbing.
Changes:
  • Introduce EventPipeCpuSamplingRate config/env var and consume it in EventPipe init (ms → ns conversion, 0 = default).
  • Implement ep_rt_config_value_get_sampling_rate() for CoreCLR, NativeAOT, and Mono runtime layers.
  • Update browser WASM SDK targets to pass DOTNET_EventPipeCpuSamplingRate (and related instrumentation env vars) and adjust websocket interop declarations.
Reviewed changes
Copilot reviewed 9 out of 9 changed files in this pull request and generated 3 comments.
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FileDescription
src/native/eventpipe/ep.cReads configurable sampling interval and applies it during ep_init().
src/native/eventpipe/ep-session.cAdds an assert in the no-threads streaming loop shutdown path.
src/native/eventpipe/ep-rt.hAdds runtime abstraction API for sampling-rate config retrieval.
src/native/eventpipe/ds-ipc-pal-websocket.hAdjusts websocket externs for C++/interop and fixes recv buffer constness.
src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targetsAdds EnableDiagnostics gating and parses WasmPerformanceInstrumentation for optional interval.
src/mono/mono/eventpipe/ep-rt-mono.hMono implementation of sampling-rate config getter via env var.
src/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.hCoreCLR implementation of sampling-rate config getter; minor preprocessor cleanup.
src/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.hNativeAOT implementation of sampling-rate config getter.
src/coreclr/inc/clrconfigvalues.hRegisters new CoreCLR config knob INTERNAL_EventPipeCpuSamplingRate.
Comment threadsrc/native/eventpipe/ep-session.c
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Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
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Comment threadsrc/mono/mono/eventpipe/ep-rt-mono.h
@pavelsavara
Update src/native/eventpipe/ep-session.c
6c03fdc
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
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review requested due to automatic review settings
April 22, 2026 18:31
@pavelsavara
Update src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Micros…
9a89ca5
…oft.NET.Sdk.WebAssembly.Browser.targets
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
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Pull request overview
Copilot reviewed 9 out of 9 changed files in this pull request and generated 2 comments.
Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
Comment threadsrc/mono/mono/eventpipe/ep-rt-mono.h
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April 23, 2026 21:59
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Copilot encountered an error and was unable to review this pull request. You can try again by re-requesting a review.
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April 24, 2026 06:28
lateralusX
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Comment threadsrc/native/eventpipe/ep-session.c
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Pull request overview
Copilot reviewed 10 out of 10 changed files in this pull request and generated 2 comments.
Comment threadsrc/native/eventpipe/ep.c
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Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
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lateralusX
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Comment threadsrc/native/eventpipe/ep.c
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LGTM!
@jkotas
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Document this in https://learn.microsoft.com/en-us/dotnet/core/diagnostics/eventpipe#trace-using-environment-variables ?
noahfalk
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Looks good to me modulo comments inline.
Comment threadsrc/coreclr/inc/clrconfigvalues.h
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Comment threadsrc/coreclr/inc/clrconfigvalues.h
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Comment threadsrc/coreclr/inc/clrconfigvalues.h
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Merge branch 'main' into browser_EP_sample_rate
96ab3a8
# Conflicts:
#	src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
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Pull request overview
Copilot reviewed 10 out of 10 changed files in this pull request and generated 6 comments.
Comment threadsrc/native/eventpipe/ep.c
Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
Comment thread...nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
Comment threadsrc/coreclr/inc/clrconfigvalues.h
Comment threadsrc/coreclr/nativeaot/Runtime/eventpipe/ep-rt-aot.h
Comment threadsrc/coreclr/vm/eventing/eventpipe/ep-rt-coreclr.h
@pavelsavarapavelsavara
changed the title
Add configurable EventPipe CPU sampling rate via DOTNET_EventPipeCpuSamplingRateAdd configurable EventPipe CPU sampling rate via DOTNET_EventPipeThreadSamplingRateApr 27, 2026
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Document this in https://learn.microsoft.com/en-us/dotnet/core/diagnostics/eventpipe#trace-using-environment-variables ?
dotnet/docs#53393

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@noahfalknoahfalknoahfalk approved these changes
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@marafmarafmaraf left review comments
@lateralusXlateralusXlateralusX approved these changes
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