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  • 1.  Are hardware performance counters supported?

    Posted Feb 09, 2009 11:04 PM

    It seems similar questions have gone unanswered in the past, but I thought I'd try again anyway. Does VMWare Workstation support hardware performance counters? In other words, would I be able to write code that triggers an interrupt on a performance counter overflow and have it run correctly in the guest OS? If VMware Workstation doesn't support this, is there another VMware product that does?

    I've stumbled across a few dated postings around the net that seem to indicate that this functionality is not available (see and below). However, because these are so old, it's quite possible newer versions have since added support.

    Thanks,

    devnull431

    http://oprofile.sourceforge.net/faq/, near the bottom, under "VMware"

    http://software.intel.com/en-us/forums/intel-vtune-performance-analyzer/topic/44195/



  • 2.  RE: Are hardware performance counters supported?
    Best Answer

    Posted Feb 09, 2009 11:46 PM

    No, the performance monitor counters are not virtualized in any VMware product.



  • 3.  RE: Are hardware performance counters supported?

    Posted Feb 10, 2009 04:57 AM

    Thanks, jmattson. I was afraid that was the case. Do you know if there is official documentation on the VMware page that details what is or is not virtualized?

    Thanks,

    devnull431



  • 4.  RE: Are hardware performance counters supported?

    Posted Feb 10, 2009 05:10 PM

    I am unaware of any such documentation.

    In addition to the PMCs, many MSRs are not virtualized. (Unsupported MSRs read as zero and sink all writes.) BTS and PEBS are also not virtualized.

    Where there are CPUID feature bits available to indicate the presence or absence of a feature, the bits for a non-virtualized feature are masked out under binary translation and under hardware virtualization. Direct execution of CPL3 code does not provide the ability to perform such masking. Features that are masked out include most power management features, MONITOR/MWAIT, x2APIC, hyper-threading, 1GB superpages, VT-x and AMD-V.