14 Replies Latest reply on Sep 20, 2016 3:59 AM by Kalegley

    Maximum CPU capacity

    lvaibhavt Hot Shot
    lvaibhavt Oct 6, 2013 1:25 AM

      Hi All,

       

      I have attached a snapshot of my virtual ESXi host in a VM workstation. This is from my lab.

      I want to know how do I calculate total CPU MHz of any esxi host ?

       

       

       

      Thanks

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        • 1. Re: Maximum CPU capacity
          lvaibhavt Hot Shot
          lvaibhavt Oct 6, 2013 1:30 AM (in response to lvaibhavt)

          I guess the attached pic answer to my question cpu details 2.PNG

           

          Please confirm

          • 2. Re: Maximum CPU capacity
            Hot Shot
            Fillips Oct 6, 2013 1:54 AM (in response to lvaibhavt)

            its 16000 Mhz also I am sending u a link where you can convert..

            Gigahertz to Megahertz Conversion Calculator

            • 3. Re: Maximum CPU capacity
              lvaibhavt Hot Shot
              lvaibhavt Oct 6, 2013 2:03 AM (in response to Fillips)

              Hi Fillips,

               

              Thanks for the reply. If my esxi has capacity of 16000 MHZ then why in the performance charts if shows that 50% of usage in MHz is done -- snapshot attached

               

              cpu details 3.PNG

               

              Also per the link if I enter 8*2.92 then it shows as 23360 MHz ..... how did you calculate 16000

               

               

              Thanks

              • 4. Re: Maximum CPU capacity
                a.p. Guru
                User ModeratorsvExpertCommunity Warriors
                a.p. Oct 6, 2013 2:05 AM (in response to lvaibhavt)

                It depends on what you are asking for. From a logical point of view you have 2 CPUs with 4 cores each which results in 8 x 2.93 MHz. However, since the cores shown on the virtual ESXi host are the logical CPUs (i.e. 4 Cores with HyperThreading) of the real host, the usable frequency may not exceed 4 x 2.93 MHz, and taking into account that the host PC itself needs processing power too, it will definitely be less than that what can be consumed by the virtual ESXi host.

                 

                André

                • 5. Re: Maximum CPU capacity
                  a.p. Guru
                  User ModeratorsvExpertCommunity Warriors
                  a.p. Oct 6, 2013 2:08 AM (in response to lvaibhavt)

                  >>> "... the performance charts if shows that 50% of usage in MHz ..."

                  The blue line doesn't show the percentage, but the MHz used, i.e. ~3,500 MHz. The red line shows the percentage.

                   

                  André

                  • 6. Re: Maximum CPU capacity
                    Hot Shot
                    Fillips Oct 16, 2013 8:53 PM (in response to lvaibhavt)

                    check overall uses showing in red line and in Mhz it showing it gray line ..here i cant explain exactly for further you can see vmeare performance chart..

                    But we can check performance chart using advance chart....there is one option...

                    Hope my ans will help u lit

                    Yours, Phillips

                    • 7. Re: Maximum CPU capacity
                      lvaibhavt Hot Shot
                      lvaibhavt Oct 6, 2013 2:52 AM (in response to a.p.)

                      Hi Andre/Fillip,

                       

                      Thanks for replying

                       

                      @ Andre --- I understand that 4 cores will be used. I have couple of questions

                      For example an Intel Processor has 2 cores. I enable hyper threading this will show in CPU as 4 logical Processors. So effective total MHz capacity will be of 2 cores only? is this correct?

                       

                      Second, in my case I agree that 4 cores are there and the calculation is 4*2.92 = 11680. The consumption is close to 3300 MHz -- this is below 40% then why in the charts it shows above 50 %?

                      cpu details 4.PNG

                      • 8. Re: Maximum CPU capacity
                        a.p. Guru
                        User ModeratorsvExpertCommunity Warriors
                        a.p. Oct 6, 2013 3:10 AM (in response to lvaibhavt)

                        HyperThreading is not comparable to a real core, but with an operating system which is able to efficiently use HyperThreading you may get a better performance. How much (15%, 25% or even more) depends on many factors, so it's hard to say which amount you can take into account.

                        Regarding the chart. Don't get confused with the left and right scale. The left one shows the MHz used (that's for the "Usage in MHz") and the right one shows the percentage ("Usage"). And as you can see the usage (red line) is ~15%.

                         

                        André

                        1 person found this helpful
                        • 9. Re: Maximum CPU capacity
                          lvaibhavt Hot Shot
                          lvaibhavt Oct 6, 2013 4:05 AM (in response to a.p.)

                          thanks Andre

                           

                          Last question ....... can consumed Host CPU on the VM console be different with the CPU utilization seen in OS?

                          If yes -- then how to go about troubleshooting it .... I have seen this nature in memory.

                           

                          cpu details 5.PNG

                           

                           

                           

                          Andre - I saw a counter Total Capacity (which by definition goes --- total cpu capcity reserved and available for virtual machines) ...... How is this counter calculated? is a link you can point me to for this

                           

                          cpu details 6.PNG

                           

                          I am sorry I have asked too many questions from you .... Thanks for assisting me

                          • 10. Re: Maximum CPU capacity
                            a.p. Guru
                            User ModeratorsCommunity WarriorsvExpert
                            a.p. Oct 6, 2013 4:14 AM (in response to lvaibhavt)

                            Yes, it can. There might be e.g. situations in which the guest is idle and therefore shows a low CPU usage in the gust OS itself, but the idle loop uses CPU cycles on the host. Furthermore, it depends where you look at the consumed values (GUI, esxtop) because there are also different sample rates which may result in different values.

                             

                            André

                            • 11. Re: Maximum CPU capacity
                              lvaibhavt Hot Shot
                              lvaibhavt Oct 6, 2013 4:20 AM (in response to a.p.)

                              Thanks Andre -- can you assist me with Total Capacity counter from my last post

                              • 12. Re: Maximum CPU capacity
                                a.p. Guru
                                User ModeratorsvExpertCommunity Warriors
                                a.p. Oct 6, 2013 4:27 AM (in response to lvaibhavt)

                                The total capacity is the "physical" capacity (8 x 2.93 GHz) minus the reservation for the ESXi host which is ~2.4 GHz in this case.

                                 

                                André

                                • 13. Re: Maximum CPU capacity
                                  lvaibhavt Hot Shot
                                  lvaibhavt Oct 6, 2013 4:41 AM (in response to a.p.)

                                  Thanks a ton Andre !!!! Thanks again for assisting me

                                  • 14. Re: Maximum CPU capacity
                                    Kalegley Lurker
                                    Kalegley Sep 20, 2016 3:59 AM (in response to Fillips)

                                    I thinks it will be 16000 Mhz. Also I am sending you a link where you can convert..

                                    Gigahertz to Megahertz Conversion Calculator

                                     

                                    Thanks !!

                                    Kalegley@Redgage