Friday, January 28, 2011

Perfmon Total Counters: 32-Bit Wrap Around?

For counters in Windows Server 2008 R2 that count the total (instead of rate) at what number do they wrap around to zero? In this particular case I am interested in \Web Service(_Total)\Total Get Requests. Are they always maybe 32bit or 64bit. Or maybe it depends on if it is a 32bit or 64bit OS (in this case, R2 so has to be 64)?

  • Normally it will be an unsigned 32 bit (on 32-bit system) so 2^32 = 4294967296. So the range is 0-4294967295.

    Kyle Brandt : Any references on that? That would be my *guess* as well, but rather find out for sure instead of a bug creeping up on me by the time I forget all about this.
    Len Holgate : Whoever writes the code that publishes the counter can decide on the size, 32 or 64 bit; so there's really no 'normally' about it. It will be dependent on the particular counter in question. It's also actually pretty unlikely that it would be different on a 64 bit OS, it's more likely that you'd decide to use a 64bit counter if the count would otherwise wrap 'regularly'.
    From Gopoi
  • It's a 32bit unsigned Integer.

    Reference: Win32_PerformattedData_W3SVC_WebService -> TotalGetRequests

    From Chris S

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