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Assigning Physical Processors to VM's

Posted: 27. May 2011, 10:33
by mrossi
Hi,

I'm wondering how VirtualBox maps the physical processor cores on the host machine to the virtual processor cores assigned to the guest OS, and if there is any way to _force_ a mapping between the two?

For example, I have a six core machine running a single VM with a single virtual CPU assigned to it. Does this mean VirtualBox has taken one of my physical cores, say CORE-0, and assigned it to that VM (i.e. The VM process' affinity is set to CORE-0 only, and can't use any others)? If this is the case, is there any way of identifying which CPU has been assigned, or even force it to use one in particular? I've tried playing around with the processor affinity setting (in Windows) for the VirtualBox process itself, and it seems to have some effect, but am wondering if there is a better way of solving the problem?

Cheers

Re: Assigning Physical Processors to VM's

Posted: 28. May 2011, 18:25
by Sasquatch
CPU allocation is done by the Host. The VM process is moved from core to core unless you specifically set the affinity to one core. To pinpoint what process the VM is running under, generate a lot of CPU so you see it in the Host task manager, then set it's affinity to one core.