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document DOTNET_EventPipeThreadSamplingRate #53393

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DOTNET_EventPipeThreadSamplingRate
pavelsavara Apr 27, 2026
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pavelsavara Apr 28, 2026
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Update docs/core/runtime-config/debugging-profiling.md
pavelsavara Apr 29, 2026
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3 changes: 3 additions & 0 deletions docs/core/diagnostics/dotnet-trace.md
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Expand Up @@ -233,6 +233,9 @@ dotnet-trace collect
|--------------|----------------------------------------------------------|
| `dotnet-common` | Lightweight .NET runtime diagnostics designed to stay low overhead.<br>Includes GC, AssemblyLoader, Loader, JIT, Exceptions, Threading, JittedMethodILToNativeMap, and Compilation events<br>Equivalent to `--providers "Microsoft-Windows-DotNETRuntime:0x100003801D:4"`. |
| `dotnet-sampled-thread-time` | Samples .NET thread stacks (~100 Hz) to identify hotspots over time. Uses the runtime sample profiler with managed stacks. |

> [!TIP]
> The sampling rate used by `dotnet-sampled-thread-time` can be changed with the `DOTNET_EventPipeThreadSamplingRate` environment variable (value in milliseconds). This setting is process-global and affects all EventPipe sessions. See [Trace using environment variables](./eventpipe.md#trace-using-environment-variables) for details.
| `gc-verbose` | Tracks GC collections and samples object allocations. |
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Copilot AI Apr 29, 2026

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The TIP block is inserted in the middle of the Markdown table for available profiles, which terminates the table after the dotnet-sampled-thread-time row and causes the gc-verbose, gc-collect, and database rows to render outside the table. Move the TIP either inside the dotnet-sampled-thread-time cell (as inline text) or place it after the table ends so the table remains contiguous.

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| `gc-collect` | Tracks GC collections only at very low overhead. |
| `database` | Captures ADO.NET and Entity Framework database commands. |
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2 changes: 2 additions & 0 deletions docs/core/diagnostics/eventpipe.md
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Expand Up @@ -84,6 +84,8 @@ However, you can use the following environment variables to set up an EventPipe

* `DOTNET_EventPipeProcNumbers`: Set this to `1` to enable capturing processor numbers in EventPipe event headers. The default value is `0`.

* `DOTNET_EventPipeThreadSamplingRate`: Available in .NET 11+. Sets the interval, in milliseconds, for the EventPipe thread time sampling profiler. When set to `0` or omitted, the runtime uses its built-in default of 10 ms (~100 Hz). This setting is process-global and affects all EventPipe sessions, including on-demand traces started by tools such as [dotnet-trace](./dotnet-trace.md). Setting a large value reduces sampling overhead but also reduces the resolution of any trace collected during the process lifetime.
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Consider rephrasing "Available in .NET 11+" to a more standard version note (for example, "Available starting in .NET 11" or "Available in .NET 11 and later") to avoid the informal "+" shorthand in docs text.

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* `DOTNET_EventPipeThreadSamplingRate`: Available in .NET 11+. Sets the interval, in milliseconds, for the EventPipe thread time sampling profiler. When set to `0` or omitted, the runtime uses its built-in default of 10 ms (~100 Hz). This setting is process-global and affects all EventPipe sessions, including on-demand traces started by tools such as [dotnet-trace](./dotnet-trace.md). Setting a large value reduces sampling overhead but also reduces the resolution of any trace collected during the process lifetime.
* `DOTNET_EventPipeThreadSamplingRate`: Available in .NET 11 and later. Sets the interval, in milliseconds, for the EventPipe thread time sampling profiler. When set to `0` or omitted, the runtime uses its built-in default of 10 ms (~100 Hz). This setting is process-global and affects all EventPipe sessions, including on-demand traces started by tools such as [dotnet-trace](./dotnet-trace.md). Setting a large value reduces sampling overhead but also reduces the resolution of any trace collected during the process lifetime.

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* `DOTNET_EventPipeConfig`: Sets up the EventPipe session configuration when starting an EventPipe session with `DOTNET_EnableEventPipe`.
The syntax is as follows:

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2 changes: 2 additions & 0 deletions docs/core/runtime-config/debugging-profiling.md
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Expand Up @@ -81,6 +81,8 @@ The following table compares perf maps and jit maps.
| **runtimeconfig.json** | N/A | N/A |
| **Environment variable** | `DOTNET_PerfMapEnabled` | `0` - disabled<br/>`1` - perf maps and jit dumps both enabled<br/>`2` - jit dumps enabled<br/>`3` - perf maps enabled |

For EventPipe-related environment variables, see [Trace using environment variables](../diagnostics/eventpipe.md#trace-using-environment-variables).

## Perf log markers

- Enables or disables the specified signal to be accepted and ignored as a marker in the perf logs.
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