[fedora-virt] 20% cpu usage spikes with idle centos 5.3 guest on F11

[Dennis J.]

On 06/25/2009 03:55 PM, Don Dutile wrote:
> Dennis J. wrote:
>> Hi,
>> When I run a centos 5.3 x86_64 guest on my F11 x86_64 system with kvm I
>> see the qemu-kvm process cpu usage jump to ~20% every few seconds even
>> though the guest is completely idle (I even disabled the HAL polling for
>> /dev/hdc). Does anyone have an idea what could be the cause of this or
>> how find the reason for this behavior?
>>
>> Regards,
>>    Dennis
>>
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>
> Try turning off the network (ifcfg eth0 down) in the guest&
> see if the cpu usage goes away.  if so, it's probably network
> polling mis-behaving.  if not, then send details
> (kernel revs; #pcpu's, #vcpu's in guest, etc.

I shut down the interface using "ifdown eth0" but that didn't change 
anything. I filed a bug here:
https://bugzilla.redhat.com/show_bug.cgi?id=508109

It contains additional information about the environment and an attached 
screenshot showing the peaks in virtual-machine-manager in more detail.

Regards,
   Dennis