Re: [ovirt-users] Ovirt VM Performance abd CPU times

On 10/29/2014 03:07 PM, Xavier Naveira wrote: > 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(a)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 >>> Actually, this seems to be it. But I'm already at a newer kernel: https://bugzilla.redhat.com/show_bug.cgi?id=705082