Vince, > I'm not sure if it's causing this particular problem for you, but check > the intel errata. There's one for this perf counter that makes the count > vary with system frequency on some machines. A core2 machine we have > exhibits this erratum.
Thank you, it is important to know that. > > I don't think that would cause a 100x difference though. > The output with sampling period set to 1000 ms (1s) looks like this (the first event is the CPU_CLK_UNHLATED:REF, the second event are cache misses - not important): CPU0 61904654 77838 CPU1 32798577 47473 # CPU0 168643020 213794 CPU1 90882904 171191 # CPU0 590366000 770770 CPU1 1172523359 1644810 However, if this irregularity of a regular event is caused by the event itself, not by pfmon, it is OK for me. I would just like to know what overhead and irregularity is exposed by using pfmon to do interval counting, so that I know am getting reasonable results. Clearly, we can't say what the overhead actually is, but knowing that it is the same as e.g. sampling with respect to regular event is a good result for me. Thanks Tom ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone _______________________________________________ perfmon2-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/perfmon2-devel
