Re: [libvirt] Query regarding sharing of vcpu's (cpu alloc ratio 1.0) between VM's

Hi Martin, To be more clear on the requirement, I have a kind of VM which needs 2 vcpu's. One of the vcpu is dedicated for a specific process in the VM and the other vcpu can be shared by other VM's of the same kind. To be more clear, each VM is having 2 processes, one cpu intensive which got a dedicated vcpu alloted and the other process is a lightweight process which needs less amount of cpu so it can be shared with the other Vm's light weight processes. Example: There are 10 VM's of same type which need 2 vcpu's each (1 dedicated and 1 shared): VM#: vcpu1, vcpu2 VM1: 1, 11 VM2: 2, 11 VM3: 3, 11 VM4: 4, 11 VM5: 5, 11 VM6: 6, 11 VM7:7, 11 VM8: 8, 11 VM: 9, 11 VM:10, 11

IS there a way openstack nova-scheduler can provision the same (does this need libvirt changes if we want to provision via nova-scheduler)?or it can only be done via boot via xml (manually via templates in virsh)?

Regards, Bharani.. On Thu, Jan 12, 2017 at 2:26 AM, Martin Kletzander <mkletzan(a)redhat.com&gt; wrote: > On Wed, Jan 11, 2017 at 11:13:52AM -0600, BharaniKumar Gedela wrote: > >> HI, >> >> I have a Q about sharing a vcpu across Vm's (cpu alloc ratio 1.0 and HT >> not >> enabled)? >> >> I have a Use case where a VM needs vcpu's and one of the vcpu is dedicated >> to the VM for some traffic processing. We want the other vcpu which is >> used >> for control processing and can be shared with a similar VM's control >> processing. >> Is this possible and support in openstack/libvirt/KVM? >> >> > I can't wrap my head around it, but do you mean something like this: > > | pCPUs | 0 | 1 | 2 | 3 | > |---------------+---+---+---+---| > | VM #0's vCPUs | 0 | 1 | 2 | | > | VM #1's vCPUs | | 0 | 1 | | > > where VM #0 uses pCPU 0 exclusively and both VMs share pCPUs 1 and 2? > > You can do that using vcpupin [1]. Do you want them to share the pCPUs > fairly? You could theoretically utilize shares/period/quota for that, > making sure that the rest of the system is set up properly as well. > > If so could you please advice how to test it? >> >> > > [1] https://libvirt.org/formatdomain.html#elementsCPUTuning > > Regards, >> Bharani.. >> > > -- >> libvir-list mailing list >> libvir-list(a)redhat.com >> https://www.redhat.com/mailman/listinfo/libvir-list >> >