Ops, missed this one. It works like a charm. Now I feel like I'm trying to reinvent the wheel. It's a lot simpler working directly with libvirt. Thanks a lot for you help. <div class="gmail_quote"> On Fri, May 11, 2012 at 7:04 PM, Eric Blake <<a href="mailto:eblake@redhat.com" target="_blank">eblake@redhat.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> <div class="HOEnZb"><div class="h5">On 05/11/2012 03:51 PM, Antonio Carlos Salzvedel Furtado Junior wrote: > Thanks for the prompt response, it cleared a lot of my doubts > > Actually, I could enable the other controllers. It's just that I have a > strong reason to use the cpu controller. > I need to set a hard limit for CPU consumption. Maybe 'cpu.shares' was a > bad example. > I'm working especially with two parameters, "cpu.cfs_period_us" and > "cpu.cfs_quota_us". For instance, sometimes I need to limit my VM to 20% of > the CPU share, regardless of the CPU load. Then I set > "cpu.cfs_period_us=100000" and "cpu.cfs_quota_us=20000". > I'm using the libcgroup API to do that, but I agree that it would be better > to use the libvirt API. > > Looking at the documentation, The parameters I'd need to change would be > the following: > > <domain> > ... > <cputune> > <period>100000</period> > <quota>20000</quota> > </cputune> > ... > </domain> > > Unfortunately, I think virsh does not have tools to change these > parameters, as libcgroup does ( cgget and cgset ). However I guess it won't > be a problem, I'll try to use the libvirt API. </div></div>virsh exposes the libvirt API; if you can't get it working in virsh, that's a bug that we should fix. That said: virsh schedinfo $dom --set vcpu_period=100000 --set vcpu_quota=20000 should do exactly what you're asking for. <div class="HOEnZb"><div class="h5"> -- Eric Blake <a href="mailto:eblake@redhat.com">eblake@redhat.com</a> <a href="tel:%2B1-919-301-3266" value="+19193013266">+1-919-301-3266</a> Libvirt virtualization library <a href="http://libvirt.org" target="_blank">http://libvirt.org</a> </div></div></blockquote></div>