Hi, I am trying to correlate timestamped samples by pfmon to timestamped events collected from the profiled program by instrumentation. The samples and events are collected from the same run. In other words, I run my instrumented program using pfmon to collect a pfmon profile and a timestamped execution trace. For pfmon I simply use the unique timestamp column value (based on TSC) and I use rdtsc for my program. My problem is that the timestamps do not match, there is always a shift that is large enough to make the first pfmon sample out of range of the collected events. I am using a dual core x86 machine. My questions are:
- I am assuming this is because of frequency scaling effect. Could it be something else ? - If I turn off freq. scaling, is it guaranteed that TSC value will be synchronized on both cores ? - I use rdtsc because it is the only way I know that enables me to read time from user-space without a syscall, so it is cheap. Is there any better ways of doing that for x86 or other architectures ? thanks, - nagy ------------------------------------------------------------------------------ This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword _______________________________________________ perfmon2-devel mailing list perfmon2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/perfmon2-devel
