[fedora-virt] Different cpu usage between Fedora and SL6 guests

[Eric Blake]

On 07/17/2012 04:50 PM, Orion Poplawski wrote:
> While staring at top on my SL6 kvm server waiting for it to crash, I
> noticed that my idle Fedora kvm guests appear to be consuming between
> 8-12% cpu while my idle SL6 guests appear to be consuming between 0.3-2%
> cpu as shown in the qemu-kvm processes in top.  In fact I have a Fedora
> 17 instance running now with nothing but kernel processes and the
> qemu-kvm process still shows it using 7-8% cpu.
> 
> Does anyone have any insight as to why this would be the case?

Could it be an issue of vnc vs. spice?  It may help if you provide the
'virsh dumpxml $dom' of the two guests in question, to point out if any
difference in configuration may be responsible.  Also bear in mind that
the virt stack strives for guest ABI compatibility - so a guest created
2 years ago will still use the defaults from 2 years ago, even if the
defaults have since improved in the meantime for a guest created today.
 You can rewrite the XML, generally with no ill effects to a Linux
guest, but at risk of having to revalidate a Windows guest (hence why
the virt stack strives for stable ABI instead of auto-rewriting your
guests to use latest-and-greatest defaults).

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



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