[libvirt-users] CPU Resource Reservation using KVM

[Jatin Davey]

On 4/13/2015 2:19 PM, Kashyap Chamarthy wrote:
> On Mon, Apr 13, 2015 at 01:41:59PM +0530, Jatin Davey wrote:
>> On 4/13/2015 1:18 PM, Kashyap Chamarthy wrote:
>>> On Mon, Apr 13, 2015 at 12:14:12PM +0530, Jatin Davey wrote:
>>>> Hi All
>>>>
>>>> I am new to KVM world. I have been using VMware for about a year.
>>>>
>>>> In VMware world we can reserve cpu resources for a VM. Say for instance if
>>>> we need 4 vCPUs with a total of 8000 GHz then we can mention this
>>>> configuration in vCenter while creating a VM. This guarantees 8000 GHz of
>>>> cpu resources for the deployed VM.
>>>>
>>>> How can i achieve the same thing using KVM ?
>>> If you are comfortable with command line, you can look at `virsh` manual
>>> page for
>>>
>>>      setvcpus - change number of virtual CPUs
>>>
>>> to control how many vCPUs you can allocate.
>>>
>>> If you're using `virt-manager`, you should be able to control it via UI
>>> for a guest under its "Show virtual hardware details" and look for
>>> "Processor".
>>>
>>>
>> I have looked at virsh and more specifically "setvcpus".
> You mention that info only now.
>
>> We can assign virtual CPUs using it but my question is different. I am
>> looking at reserving cpu speed to the virtual cpu's. I know we can
>> allocate and modify the amount vcpu's using setvcpus command but how
>> can i ask kvm to reserve a particular amount of cpu speed of the host
>> core's to the virtual cpus.
> Okay. I don't notice an option to regulate CPU freq. But the closest I
> see is the 'quota' XML attribute (as part of 'cputune' element) that
> will "ensure that all vcpus run at the same speed."
>
>      https://libvirt.org/formatdomain.html#elementsCPUTuning
>
>
Yes , The information provided in this link is what precisely i wanted 
to know. Thanks for pointing to it.

Thanks
Jatin