Hi, - Regards, Sethuraman Subbiah Graduate Student - NC state University M.S in Computer Science On Oct 24, 2011, at 4:20 PM, Eric Blake wrote:
On 10/24/2011 01:50 PM, sethuraman subbiah wrote:
Hi ,
I was previously using xen and currently moved to KVM. I am using libvirt to manage these VMs. In den's credit scheduler , I had the ability to set a cap on the cpu usage for a VM. But I was not able to find a similar substitute in KVM. I find that we can use cgroups to provide shares for VM but that will be more like weight based and it doesn't set a hard cap for that VM. I tried using cpulimit but I find it inaccurate and we can give values only between 0-100. Thus, I think it cannot support multi core environments. Can any one suggest a method to set a hard limit on a VM's cpu usage? Thank you.
Libvirt 0.9.4 added CPU bandwidth limitation support, via <cputune>: http://libvirt.org/formatdomain.html#elementsCPUTuning. <period> and <quota> map to hard-coded caps via cgroups, nicer than the weighted numbers via <shares>.
Great, I have one more question. Is it possible to set the quota during run time from the host os ? Using virsh ? Thank you.
-- Eric Blake eblake@redhat.com +1-801-349-2682 Libvirt virtualization library http://libvirt.org