Hello I've encounterd an odd problem when using perfmon2 on an r12k MIPS machine (an SGI Octane).
The spec2k sixtrack benchmark runs with normal results on the machine. However, if I use perfmon2 to collect CYCLES on the same executable, the reported floating point results are off, maybe by 5% from what they should be. If I use perfmon2 to collect both CYCLES and INSTRUCTIONS_GRADUATED, the program will actually crash due to floating point errors. I'm at a bit of a loss as to why this could happen. Perfmon shouldn't have any affect on floating point results, should it? I'm doing just plain aggregate counts so the perfmon code should not really be doing much except handling overflows of the counters. The only thing I can think of is maybe the context-switch code is somehow modified in a way that affects the saving of FPU state. I'm going to investigate this some more myself, I was just curious if anyone had any ideas of where to look in a strange case like this. Unfortunately I am running an older kernel (2.6.22) on this machine due to the SGI Octane hardware support not being in the mainline kernel yet. So this might be fixed in later versions of perfmon2. Thanks Vince ------------------------------------------------------------------------------ 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
