Re: [libvirt-users] CFS BWC related question
On 12/14/2012 11:04 PM, Eric Blake wrote:
On 12/14/2012 12:37 AM, Dennis Chen wrote:
> Hi,
>
> Seems this question is not related with libvirt directly, but I still want to ping
this list to see if someone can be help.
>
> The OS in my desktop box is Ubuntu 12.10, the kernel is 3.5.1. I installed the cgroup
utility package with:#apt-get install cgroup-bin, but after I installed these packages
successfully, I can't find cpu_quota/cpu_period controller in the /sys/fs/cgroup/cpu
folder. So the essential question is:
>
> What I need to do to make cgroup can support CFS BWC feature?
Your kernel sounds new enough, and since you have cgroups turned on,
libvirt should just be able to use it. Did you restart libvirtd after
turning on cgroups?
I tried restart the libvirtd but seems this approach is not effective...
> Specifically, how to make the cpu_quota/cpu_period to be
available within cgroup/cpu?
Have you tried using the libvirt XML markings that control cpu quota
and period? If so, it either works (you have everything you need), or
else it would be helpful if you posted the error message you get when trying.
For reference, the XML to use is documented at:
http://libvirt.org/formatdomain.html#elementsCPUTuning
and you can also do hot-plug modifications by using virsh schedinfo.
Yes, I tried. Below is the error info when I tried to start the vm with the
modified xml file:
virsh # create /etc/libvirt/qemu/odm.xml
error: Failed to create domain from /etc/libvirt/qemu/odm.xml
error: Unable to get cpu bandwidth period: No such file or directory
As the hot-plug method, the virsh will complain:
virsh # schedinfo odm --set cpu_period=1000000
Scheduler : posix
error: invalid scheduler option: cpu_period=1000000
So I think the root cause is no cpu_period/quota in my installed cgroup folder.
Interesting, I remembered a couple of weeks ago, I had an older Linux distribution
installed, the cpu_period/quota is there.
BRs,
Dennis