How to figure out events in the profiler?

In the profiler there are a dozen places where I see “CPU Stall - Wait for Event”. It would be nice to actually know which event that was. I looked at the source and these events are rather obscure as they don’t contain any debugging information so I don’t know who issues them. In some cases I discovered that an event that the game thread was waiting for was related to rendering but that was just a lucky hunch. Any insights on this ?