Message Edited by email@example.com on 11-03-2005 05:00 PM
You are very right! One run is optimal!! However, if you study the processor manual, you will see that selecting some event in one event control register limits the events available in the next register, and etc. So, the processor may very well have 18 registers, but based on the events you have selected, there may be no way to collect them all in one run.
The VTune analyzer uses an algorithm to attempt to collect as many events at a time as possible. It is probably not perfect and I have heard some discussion of a new algorithm that improves the use of the event registers. We'll have to wait an see if that shows up in a future release.
Thanks for your reply. I also noticed sometimes VTune got the problem when I combined two events together. If I sampled these two events in separate sampling activities, then VTune has no problem.