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

# Maximum CPU capacity

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

• ###### 1. Re: Maximum CPU capacity

I guess the attached pic answer to my question

• ###### 2. Re: Maximum CPU capacity

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

Gigahertz to Megahertz Conversion Calculator

• ###### 3. Re: Maximum CPU capacity

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

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

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

>>> "... 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

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

Hi Andre/Fillip,

@ 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 %?

• ###### 8. Re: Maximum CPU capacity

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

• ###### 9. Re: Maximum CPU capacity

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.

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

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

• ###### 10. Re: Maximum CPU capacity

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

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

• ###### 12. Re: Maximum CPU capacity

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

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

• ###### 14. Re: Maximum CPU capacity

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