The !wmitrace.dynamicprint extension controls whether the debugger displays the trace messages generated by a session running in KD_FILTER_MODE.

!wmitrace.dynamicprint {0 | 1}


Turns the trace message display off.

Turns the trace message display on.


This extension is exported by Wmitrace.dll.

This extension is available in Windows 2000 and later versions of Windows. If you want to use this extension with Windows 2000, you must first copy the Wmitrace.dll file from the winxp subdirectory of the Debugging Tools for Windows installation directory to the w2kfre subdirectory.

Additional Information

For a conceptual overview of event tracing, see the Microsoft Windows SDK. For help in starting a trace session, see "Tracelog" in the Windows Driver Kit (WDK).


Before you use this extension, start a trace session, and specify that the trace messages should be sent to the debugger. For example, if you use !wmitrace.start to start the session, use the -kd parameter. If you use Tracelog to start the trace session, use its -kd parameter. Tracelog (tracelog.exe) is a trace controller included in the Windows Driver Kit.

Trace messages are held in a buffers on the target computer. Those buffers are flushed and sent to the debugger on the host computer at regular intervals. You can specify the flush timer interval by using the -kd parameter of the !wmitrace.start command or the -kd parameter of the Tracelog tool. Starting in Windows 8, you can specify the flush timer value in milliseconds by appending ms to the flush timer value.

By default, ETW maintains per-processor trace buffers on the target computer. When the trace buffers are flushed and sent to the debugger on the host computer, there is no mechanism for merging the buffers into a chronological sequence of events. So the events might be displayed out of order. Starting in Windows 7, you can solve this problem by setting the -lowcapacity parameter when you use the Tracelog tool to start a trace session.

Tracelog MySession -kd -lowcapacity

When you start a session with -lowcapacity set, all events go to a single buffer on the target computer, and the events are displayed in the correct order in the debugger on the host computer.

Also, before using this extension, use !wmitrace.searchpath or !wmitrace.tmffile to specify the trace message format files. The system uses the trace message format files to format the binary trace messages so that they can be displayed as human-readable text.

See also


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