Creating an EventPipeProvider with no keywords filters out any event with keywords

[davmason]

If I create an eventpipe provider and specify no keywords:

new EventPipeProvider("MyEventSource", EventLevel.Verbose)

It will filter out any events with keywords. This is the opposite behavior of what I would expect. My expectation going in would be that if I specify no keywords I get all events, and only if I specify keywords then will it filter.

Keywords should default to 0xFFFFFFFFFFFFFFFFF and not 0x0.

[davmason]

cc @sywhang

[davmason]

Follow up info, EventSources always include a SessionMask in their keywords, so any EventSource event will be written with the keywords 0xF00000000000. This means if you use the default value of keywords for EventPipeProvider you won't ever get any of your EventSource events

[sywhang]

This was done intentionally to keep the behavior consistent with EventListener. When you call EventListener.EnableEvents(EventSource source, EventLevel level), it'll call Enable with no keywords. I didn't want someone who is already used to consuming events via EventListener to use this expecting it to work the same way.

[davmason]

Even if that is the intention, there is a bug in the implementation because EventPipe doesn't filter out the EventSource's private mask from the keywords. So if you have an EventSource event with no keywords it will come through on an EventListener if you don't specify any keywords, but you won't get those events from an EventPipe session because it will see the keywords as 0xF00000000000 (SessionMask.MASK) and filter out the event.

[sywhang]

Agreed :) I'll put up a fix for that one. Thanks David!