[libvirt-users] Hard limit for the cpu usage of a VM

[Eric Blake]

On 10/24/2011 02:39 PM, sethuraman subbiah wrote:
> Hi,
>
> On Oct 24, 2011, at 4:30 PM, Eric Blake wrote:
>
>> On 10/24/2011 02:24 PM, sethuraman subbiah wrote:
>>> Great, I have one more question. Is it possible to set the quota during run time from the host os ? Using virsh ? Thank you.
>>
>> virsh schedinfo can both query and alter these cpu tunables, and that includes doing it while the guest is running.
>>
> I tried the virsh schedinfo. Here is the information regarding my libvirt :
>
> [root at sbc11 ssubbiah]# virsh version
> Compiled against library: libvir 0.9.4
> Using library: libvir 0.9.4
> Using API: QEMU 0.9.4
> Running hypervisor: QEMU 0.12.1
>
> When i use "[root at hgcc11 ssubbiah]# virsh schedinfo rubis_ws --cap 50" , I dont see the cap value being set and I am able to see only cpu shares.

schedinfo --cap is obsolete (it's xen-only).  Rather, you want:

virsh schedinfo domain

to list the current settings, and

virsh schedinfo domain --set vcpu_period $value --set vcpu_quota $value

I haven't used it myself; I'm only going off the documentation provided 
by Wen Congyang, who oversaw the addition of the features.

-- 
Eric Blake   eblake at redhat.com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org