Correcting the Process level measurements of CPU time for Windows guest machines running under VMware ESX
Recently, I have been writing about how Windows guest machine performance counters are affected by running in a virtual environment, including publishing two recent, longish papers on the subject, one about processor utilization metrics and another about memory management. In the processor utilization paper, (which is available here ), it is evident that running under VMware, the Windows performance counters that measure processor utilization are significantly distorted. At a system level, this distortion is not problematic so long as one has recourse to the VMware measurements of actual physical CPU usage by each guest machine. A key question – one that I failed to address properly, heretofore – is whether it is possible to correct for that distortion in the measurements of processor utilization taken at the process level inside the guest machine OS. The short answer for Windows, at least, is, “Yes.” The % Processor Time performance counters in Windows that are available at the proces...