CPU Ready issue

[chicojr]

We have several servers all vms, all windows server win svr 2012 r2, 12 core, 65gb of mem.

Why do I have only 1 cpu in use? Is this an application or IIS issue where it needs to be configured to use all cpu's?

[admin]

You need change the view of task manager to show the all processors... to do this, right click on Graph -> Change Graph to -> Logical Processors.

[chicojr]

thanks for that insight, but this is vsphere related as to why all cpus minus one shows ready. Why is that?

[unsichtbare]

Couple things to think about:

1. You are clearly using more than one CPU. THe Usage is an average of all vCPUs assigned to the VM.
2. On the chart you have provided, CPU Ready is shown in milliseconds. To calculate percentage, divide by 20,000 (it's a 20 second refresh rate for the chart, so the milliseconds shown are a fraction of 20 seconds or 20,000 milliseconds) You seem to have about 0.3% Ready per core, which is nothing!
3. It's likely you have over-subscribed your CPU (assigned more than you need).
   1. On a physical PC having more pCPU than you need never hurts.
   2. On a VM, having more vCPU than you need assigned to a VM causes scheduling difficulties known as Co-Stop (%CSTP). %CSTP is one of the worst things for the performance, not only of the affected VM, but all VMs in the environment

Think about Co Stop like people and buses in traffic, where people represent threads and buses represent vCPU: Which is more efficent - Thirty passengers in thirty buses, or thirty passengers on one bus.