Exclusive access to physical CPU for specific VM

asked 2017-04-04 10:23:39 -0600

plyth gravatar image

(I'm something of an OpenStack n00b, so apologies in advance for my uninformed question!)

Is there a way (using Libvirt / KVM) to request that a certain guests vCPU is always allowed exclusive access to a physical CPU (or a number of physical CPUs) on the host, while still allowing other VMs to share the remaining CPU resources on the host (with over-allocation).

I understand that it's possible to do CPU pinning, but I think that requires a detailed knowledge of the underlying HW architecture, which I can not be sure to have. I'm looking for something like a flag saying "start this VM on a free CPU core (or CPU cores) and whichever CPU core (or CPU cores) that this VM starts up on, can not be used by anyone else"

There are some discssions on the subject here: https://wiki.openstack.org/wiki/VirtDriverGuestCPUMemoryPlacement (https://wiki.openstack.org/wiki/VirtD...) but it doesn't seem to cover my case, as far as I can tell.

Thanks!

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