Event tracing

You can use Event Tracing for Windows (ETW) or the Windows software trace preprocessor (WPP) to trace the operations in your HID over I²C device driver. For more information about ETW, see the Event Tracing topic in the Windows Development Reference. For more information about WPP, see WPP Software Tracing and Inflight Trace Recorder (IFR) for logging traces.

Using the Inflight Trace Recorder (IFR)

The Inflight Trace Recorder (IFR), that is enabled by default for all drivers, lets you view trace output from the HIDI²C driver to a kernel debugger. The following command displays WPP trace messages for HIDI²C.

!rcdrkd.rcdrlogdump hidi2c

The Inflight Trace Recorder (IFR) stores these trace messages in a fixed-size circular buffer. As a result, the output may not contain the entire trace log.

Using logman.exe

For more verbose and controllable traces, you can use logman.exe to capture traces. The following commands capture WPP traces for HIDI²C:

Logman create trace -n HIDI2C_WPP -o HIDI2C_WPP.etl -nb 128 640 -bs 128 
Logman update trace -n HIDI2C_WPP -p {E742C27D-29B1-4E4B-94EE-074D3AD72836} 0x7FFFFFFF 255
Logman start –n HIDI2C_WPP

<RUN your SCENARIO here>

Logman stop -n HIDI2C_WPP
Logman delete -n HIDI2C_WPP

You can parse the resulting trace log file into text using either the PDB or TMF files for HIDI²C.

Enabling ETW tracing

The HIDI²C driver logs ETW events for specific events. These events are logged in the Event Viewer logs.

You can also view these events using the following logman.exe commands:

Logman create trace -n HIDI2C_ETW -o HIDI2C_ETW.etl -nb 128 640 -bs 128 
Logman update trace -n HIDI2C_ETW -p Microsoft-Windows-SPB-HIDI2C 
Logman start –n HIDI2C_ETW

<RUN your SCENARIO here>

Logman stop -n HIDI2C_ETW
Logman delete -n HIDI2C_ETW

The resulting trace log can parsed with tools like Xperf or Windows Performance Analyzer (WPA).

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