Re: [libvirt] [PATCH 5/6] qemu: Implement hypervisor's period and quota tunable XML configuration and parsing

(2012/05/17 15:05), Wen Congyang wrote: > At 05/17/2012 01:42 PM, Hu Tao Wrote: >> On Thu, May 17, 2012 at 01:25:48PM +0800, Wen Congyang wrote: >>> At 05/17/2012 01:09 PM, KAMEZAWA Hiroyuki Wrote: >>>> (2012/05/17 14:07), Wen Congyang wrote: >>>> >>>>> At 05/17/2012 12:46 PM, KAMEZAWA Hiroyuki Wrote: >>>>>> (2012/05/17 12:54), Wen Congyang wrote: >>>> >>>>>>> So, if we donot limit the hypervisor, the behavior shoule not be >>>>>>> changed. So we should limit the whole vm. If the hypervisor threads >>>>>>> are limited, there is no need to limit the whole vm. >>>>>>> >>>>>> >>>>>> >>>>>> need to tune hypervisor quota to limit vcpu-only quota ? >>>>>> Sounds strange to me. >>>>> >>>>> No, current implemetion is: >>>>> 1. limit vcpu and hypervisor: vm is not limited >>>>> 2. limit vcpu only: vm is limited >>>>> 3. limit hypervisor: vm is not limited >>>>> 4. vcpu and hypervisor are not limited: vm is not limited. >>>>> >>>> >>>> >>>> In 2. >>>> >>>> vm ----- quota_is_limited >>>> |- hypervisor ----- quota is unlimited >>>> |- vcpu[0...x] ----- quota is limited >>>> >>>> Hm...vm is limited. It seems user need to tune vm's quota...can user >>>> makes vm's quota to be unlimited and limit *only* vpcus as Xen ? >>> >>> Without this patchset, the vm will be limited if the vcpu is limited. >>> We cannot know whether the hypervisor is unlimited or the user does not >>> set it. If the user does not set it, we should not change the behavior. >>> So I donot find an easy way to limit only vcpus. >> >> Can we change the implementation like these: >> >> 1. >> <cputune> >> <vcpu> >> <period>period</period> >> <quota>quota</quota> >> </vcpu> >> </cputune> >> >> Limit vcpus only, does not limit vm or hypervisor. >> >> 2. >> <cputune> >> <hypervisor> >> <period>period</period> >> <quota>quota</quota> >> </hypervisor> >> </cputune> >> >> Limit hypervisor only, does not limit vm or vcpus. >> >> 3. >> <cputune> >> <period>period</period> >> <quota>quota</quota> >> </cputune> >> >> Limit the whole vm, in this case vcpus and hypervisor are also limited. >> >> 4. >> <cputune> >> <period>period</period> >> <quota>quota</quota> >> <vcpu> >> <period>period</period> >> <quota>quota</quota> >> </vcpu> >> <hypervisor> >> <period>period</period> >> <quota>quota</quota> >> </hypervisor> >> </cputune> > > This is very complex, and the user should know how we implement it > and the period/quota's limit. If the user gives a wrong value, the > vm cannot start. > > We implement the limit like this: > > vm > | > ---------------------------- > | ... | | > vcpu0 vcpun hypervisor > > If all is limited, the vm's quota should be greater than max(vcpu's quota, hypervisor's quota) > and vm's period should be less than min(vcpu's period, hypervisor's period). > > So I donot like this idea. > Hmm. my proposal is not so complicated as you say. And simpler than your way. <quota target='all|vcpu'> </quota> # all is default and limit the whole vm. # vcpu is just limit vcpus rather than whole vm. <period> .... </period> # period is shared in all settings. Isn't it ?

Thanks, -Kame