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". 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. Thanks Jatin
Kashyap Chamarthy
2015-Apr-13 08:49 UTC
Re: [libvirt-users] CPU Resource Reservation using KVM
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 -- /kashyap
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