CPU

[AmitPawar]

Hi,

I have ESX server with AMD Dual core 2.6 GHZ, on which i have three VMs ,

one with 1 vCPU and cpu resource limit set to 1300 Mhz

Second with 1 vCPU and cpu resource limit set to 2600 Mhz

and third 2 VCPU and limit set to 5200Mhz

But when i enter the guest OS (win2003 server) and click on my computer properties all show Processor as 2.61 Ghz.

Could you pls tell how is this? does none of the VM has impact of the limit set.

Thanks,

Amit

[weinstein5]

The guest O/S in your VM sees the physical CPU which is a 2.6 GHz - it does not know about limit being imposed by the VMkernel but it will only receive the number of cycles allocated by the set limit and in the case of the dual vCPU VM each vCPU is only scheduled to a single core which is a 2.6 GHz core -

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[cf13 · Accepted solution]

Windows guest OS always sees physical cores of CPU, for example 2 VCPU means 2 cores.

So in your environment, two of your VMs should show in Device Manager "Processors" tab one 2,6 GHz CPU and the third VM - two 2,6 GHz CPUs.

Limit means upper limit that VM can get. It does not affect what Windows display but it works.

[AntonVZhbankov]

VM always see CPU at full speed. 1300 MHz limit means only that ESX will give time slice amount equal to 1300MHz exclusive usage. After you normalize that, when you give 100% load to this particular VM, you will see 50% load (1300/2600) on one core.

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VMware vExpert '2009

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