Processor to socket mapping

[Lioh]

Hi all. I have set up the following processor settings on a Windows VM:



And wonder why the Cores are split 6:4 instead of 5:5



Greetings
Lioh

 

[fabian]

because it starts at the first one and stops at 10/12

 

[Lioh]

But why not 5/5. Does it only work with even numbers, like 6/6?

 

[fabian]

you define a maximum of 12 virtual CPUs, but boot with 10. the layout (6+6) is derived from the maximum so that you can hotplug/remove vCPUs while the VM is running

 

[Lioh]

Yes, that's clear. Thanks. The question was related to the Logical Processors per Socket/Numa split. It seems that on 10 vCPUs it splits like 6:4 instead of 5:5 which might be related to the fact that it only splits on even numbers. So on 12 vCPUs it would probably split 6:6

 

[fabian]

if you plug all 12 of your vCPUs, then yes, they will be split 6:6. but this has nothing to do with even counts. you always have at least 1 vcpu. after that you start filling the first socket, then the second socket, then the third socket, and so on.. a completely even distribution will only happen when you plug in all of them.