QEMU Virtual CPU version

[Daniel P. Berrange]

On Wed, Dec 19, 2012 at 03:43:37PM +0000, Nux! wrote:
> Hi chaps,
> 
> On virtual machines deployed through Openstack folsom on EL6 I can
> see the CPU type in /proc/cpuinfo is something like "Intel Core 2
> Duo P9xxx",
> whereas in VMs deployed on vanilla EL6+libvirt the CPU type is "QEMU
> Virtual CPU version (cpu64-rhel6)".
> Now, as to avoid confusion and weird questions from my users, I'd
> like to have "QEMU Virtual CPU version" on the Openstack VMs, too.
> How do I convince Openstack to do this for me?

If you don't tell libvirt to use any particular CPU, the KVM guests
will be given a crappy default CPU model, with minimal features.
That is what you're seeing with "QEMU Virtual CPU"

As of Folsom OpenStack will expose the best possible CPU to the
guest based on what CPUs your host has available. This is a
good thing because it maximises the performance of your guest.
This is what you're seeing with the "Intel Core 2 DuO" string.

  http://wiki.openstack.org/LibvirtXMLCPUModel


You really don't want to change the OpenStack config unless
you actually want worse performance for your guests.

Daniel
-- 
|: http://berrange.com      -o-    http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org              -o-             http://virt-manager.org :|
|: http://autobuild.org       -o-         http://search.cpan.org/~danberr/ :|
|: http://entangle-photo.org       -o-       http://live.gnome.org/gtk-vnc :|