4 Replies Latest reply on Nov 28, 2019 4:43 PM by zeebahi

    VM  CPU utilization

    zeebahi Novice

      Hi everyone,

      Please consider the following example:

      VM1- --ESXi_1


      Above ESXi-1 has single VM1.

       

      ESXi-1 has following CPU resource:

      ESXI1-CPU-VM1.PNG

       

       

      We assign VM1 single CPU:

       

      VM1-CPU.PNG

       

       

      Based on the above, what is max CPU resources VM1 can use? Should it not be more than  2.59 GHZ because ESXI has two logical CPU of 2.59GHZ each and VM1 is using single vCPU which is scheduled on a single  Logical CPU on ESxi-1 at any given time.

       

      Thanks and have a good day!!

        • 1. Re: VM  CPU utilization
          daphnissov Guru
          vExpertCommunity Warriors

          If you have one vCPU assigned to this VM and the underlying pCPU is of frequency 2.59 GHz, assuming hyperthreading is in use here you may be able to use slightly more from a frequency perspective. If you look at the total resources consumed by this VM at the ESXi host level, it will be a little higher than that because ESXi consumes some of its own resources in order to run VMs. This is known as overhead.

          • 2. Re: VM  CPU utilization
            zeebahi Novice

            Thanks for you response.

            I just started learning  ESXi , basically this how i visualize :

             

            vCPU--I/O -Scheduler--I/O--pCPU

            Based on above, vCPU  can not exceed pCPU  (  ignoring  slight ESXi's overhead required for VM)

            Am i on the right track ?

             

            Thanks and have a good day!!

            • 3. Re: VM  CPU utilization
              daphnissov Guru
              Community WarriorsvExpert

              If you are new to ESXi and vSphere, I would actually recommend that you do some reading of the Mastering vSphere series. This is well as other books are some great resources to help newcomers learn the technology.

              • 4. Re: VM  CPU utilization
                zeebahi Novice

                Thanks  for the guidance.  I just ordered it.

                 

                Have a nice day!!