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

[Wen Congyang <wency cn fujitsu com>]

At 07/04/2011 07:19 PM, Nikunj A. Dadhania Write:
> On Thu, 30 Jun 2011 11:13:18 +0800, Wen Congyang <wency cn fujitsu com> 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.

> 
> Regards,
> Nikunj
>