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Ke1th
Contributor
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‎09-13-2017 07:12 PM
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How to calculate vCPU:pCPU ratio

I want to get the ratio of vCPU:pCPU, For pCPU, do i need to taking in to account Hyperthread(Logical Processors)? Or just the Physical CPU numbers?

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vijayrana968
Virtuoso
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‎09-13-2017 10:13 PM
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You should consider pCPUs (including Cores) only. Hyper-threading does not actually double the available pCPU. Hyper-threading works by providing a second execution thread to a processor core. When one thread is idle or waiting, the other thread can execute instructions. This can increase efficiency if there is enough CPU Idle time to provide for scheduling two threads, but in practice performance increases are up to a maximum of 30% and are strongly application dependent.

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senthilkumarms8
Enthusiast
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‎09-13-2017 07:33 PM
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You have only consider the physical core. As, the hyper threads will not give double the performance..

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vasan22in
Enthusiast
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‎09-13-2017 08:47 PM
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Hello,

Refer the below article...how ESXi CPU and vCPU works...

How to decide vCPU to CPU ratio for your VMware environment?

Please consider marking this answer "correct" or "helpful" if you think your query have been answered correctly. Thanks, Srini
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vijayrana968
Virtuoso
Virtuoso
‎09-13-2017 10:13 PM
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You should consider pCPUs (including Cores) only. Hyper-threading does not actually double the available pCPU. Hyper-threading works by providing a second execution thread to a processor core. When one thread is idle or waiting, the other thread can execute instructions. This can increase efficiency if there is enough CPU Idle time to provide for scheduling two threads, but in practice performance increases are up to a maximum of 30% and are strongly application dependent.

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