How do I update the flags in a running trace session?
Flags and levels are properties of a trace provider, not of the trace session. Therefore, tracelog -update, the command to update the trace session, cannot be used to change the properties of a provider. Instead, use the tracelog -enable command to re-enable the provider with the new properties.
You can also use TraceView to change the flags or levels in a trace session that you started by using TraceView. The graphical user interface makes it easy to see what properties can be changed while the session runs, and to change them.
Build date: 2/13/2014