The VSPerfCmd.exe Events option controls Event Tracing for Windows (ETW) logging. ETW data is saved to an .etl file that is separate from the profiler data file. The data can be viewed in a report using the VSPerfReport /summary:etw command.
The Events option can be called at any time before the VSPerfCmd Shutdown command is called to stop profiling.
When CLR ETW events are enabled, additional startup data is also collected in the Trace View report. To exclude startup events from appearing in the report, use the following command:
C:\<path>VSPerfCmd -events on, \".NET Common Language Runtime\", 0x7fffffff, 5
If you do not exclude the startup events, then because these events are not listed in the Managed Object Format (MOF) file, they appear as GUIDs in the report. For more information, see this page on the Microsoft Web site: Sample Managed Object Format (MOF) File.