VMware Performance Monitor: How does aggregation work for VM Processor\% Processor Time

performancevmware-esxivmware-vspherewindows-server-2008windows-server-2008-r2

I'm monitoring a Windows Server 2008 R2 SP1 VM running on vSphere 5.1 for CPU bottlenecks.
I'm using Performance Monitor and configured a few counters. Two of which are Processor\% Processor Time and VM Processor\% Processor time, the latter is provided by VMware if you have VM Tools installed.

I'm seeing a big difference in CPU time as reported by these two counters. I'm thinking that VM Processor\% Processor Time would be the one providing the more relevant data since it's showing me utilization from the Hypervisor's view and how much the VM is using out of what is really assigned to it.

What i have a problem with is knowing the maximum value for this counter. So far it's showing me utlization upward of 250%. I think this is because it gives each vCPU (vCore?) a 100%. But I still can't figure out what the maximum should be. The VM shows me 2 Xeon E5-2680 CPUs with 4 cores, 4 logical processors each. Would this mean that VM Processor\% Processor Time (_Total) max value should be 800%?

I have tried adding All Instances instead of _Total for this counter, hoping it would show me how many cores or logical processors it's monitoring individually but that didn't work. You can only add _Total.

Best Answer

I found the answer. VM Processor\% Processor Time assigns 100% to each vCPU. therefore VM Processor\% Processor Time (_Total) maximum value will be 100*(no. of vCPUs)