[ovirt-users] Ovirt VM Performance abd CPU times

[Xavier Naveira]

On 10/29/2014 01:26 PM, Daniel Helgenberger wrote:
> On 29.10.2014 11:48, Xavier Naveira wrote:
>> On 10/29/2014 11:47 AM, Xavier Naveira wrote:
>>> On 10/29/2014 11:40 AM, Daniel Helgenberger wrote:
>>>>
>>>>
>>>> On 29.10.2014 10:21, Xavier Naveira wrote:
>>>>> Hi,
>>>>>
>>>>> We are migrating our ifrastructure from kvm+libvirt hypervisors to
>>>>> ovirt.
>>>>>
>>>>> Everything is working fine but we're noticing that all the qemu-kvm
>>>>> processes in the hypervisors take a lot of CPU.
>>>> Without further details of the workload this is hard tell. One Reason I
>>>> can think of might be KSM [1]. Is it enabled on your cluster(s)? What is
>>>> your mem over-commitment setting?
>>>>
>>>> Note, IIRC the KSM policy is currently hard coded; it will start at 80%
>>>> host mem usage.
>>>>
>>>> [1] http://www.ovirt.org/Sla/host-mom-policy
>>>>>
>>>>> The typical example is an idle machine, running top from the machine
>>>>> itself it reports cpu use percentages below 10% and loads (with 2
>>>>> processors) of 0.0x. The process running that machine in the hypervisor
>>>>> rports cpu uses in the order of the 80-100%.
>>>>>
>>>>> Should the values look like this? Why are the idle machines eating up so
>>>>> much CPU time?
>>>>>
>>>>> Thank you.
>>>>> Xavier
>>>>>
>>>>> _______________________________________________
>>>>> Users mailing list
>>>>> Users at ovirt.org
>>>>> http://lists.ovirt.org/mailman/listinfo/users
>>>>>
>>>>
>>>
>> Hi, thank you for the answer.
>>
>> I've been trying to work out some pattern and realized that the VMs
>> using that much cpu all are Redhat 5.x, the Readhat 6.x doesn't exhibit
>> this kind of high cpu use. (we run only redhat/centos 5.x/6.x on the
>> cluster)
> What OS are the hosts running? In case of EL6, make sure you have
> tuned-0.2.19-13.el6.noarch installed [1].

That's exactly the version we've in the hypervisors.

>
> To further investigate please post Engine, VDSM, libvirt and kernel
> versions from the hosts.

vdsm-xmlrpc-4.14.11.2-0.el6.noarch
vdsm-cli-4.14.11.2-0.el6.noarch
vdsm-python-4.14.11.2-0.el6.x86_64
vdsm-4.14.11.2-0.el6.x86_64
vdsm-python-zombiereaper-4.14.11.2-0.el6.noarch

libvirt-client-0.10.2-29.el6_5.12.x86_64
libvirt-0.10.2-29.el6_5.12.x86_64
libvirt-lock-sanlock-0.10.2-29.el6_5.12.x86_64
libvirt-python-0.10.2-29.el6_5.12.x86_64

2.6.32-431.23.3.el6.x86_64 #1 SMP Wed Jul 16 06:12:23 EDT 2014 x86_64 
x86_64 x86_64 GNU/Linux


>
> [1] https://access.redhat.com/solutions/358033
>>
>> I'll take a look to the KSM config.
>>
>> Cheers,
>>
>> Xavier
>>
>