On Wed, Dec 4, 2013 at 12:00 AM, Eric Blake <eblake@redhat.com> wrote:

On 12/03/2013 12:52 AM, Nicolas Sebrecht wrote:

> This is about CPU affinity. You may look at CPU pinning with 'vcpupin'
> in the manual of virsh. It is possible to enable vCPU pinning in libvirt
> guest XML.
>
> Don't know if libvirt supports applying CPU affinity at guest runtime

Yes, 'virsh vcpupin' can be used to change CPU affinity at runtime.

my case is

migrate vm from core 0 to core 1 and get the downtime

does" virsh vcpupin" work for me, and can you point me the whole step

Lei

> but you could do it with usual tools (taskset, htop, etc).

Going behind libvirt's back may lead to unexpected surprises. Also,
preferring the libvirt interfaces for changing CPU affinity gives you
better flexibility of changing things even when using remote URIs (you
don't have to open separate ssh sessions to the remote machines to run
secondary tools).

--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org