Re: [libvirt] [PATCH 06/10] vcpubandwidth: introduce two new libvirt APIs

At 07/04/2011 07:19 PM, Nikunj A. Dadhania Write: > On Thu, 30 Jun 2011 11:13:18 +0800, Wen Congyang <wency(a)cn.fujitsu.com&gt; wrote: >> We want to control bandwidth for each vcpu, so we can not use the >> API virDomainSetSchedulerParameters(). Introduce two new APIs to >> change and query bandwidth for each vcpu. >> > Will we have different cpu bandwidth for different vcpus? > > Something like this: > > vcpu1: 1000000/250000 > vcpu2: 1000000/500000 > vcpu3: 1000000/300000 > vcpu4: 1000000/400000 > > IMO, that is not required, we can have a top level bandwitdh for the VM > and then redistribute it among vcpus equally, without user knowing about > it. > > Something like this: > > VM1(4vcpu) has to be throttled at 1CPU bandwidth using SetSchedParamters. > > Internally libvirt splits it equally: > vcpu1: 1000000/250000 > vcpu2: 1000000/250000 > vcpu3: 1000000/250000 > vcpu4: 1000000/250000 > > So why introduce VCPU level apis? Adam Litke said IBM's performance team nead to control cpu bandwidth for each vcpu.