[ovirt-users] Re: Possible sources of cpu steal and countermeasures

Hi, I'm having performance issues with a ovirt installation. It is showing high steal (5-10%) for a cpu intensive VM. The hypervisor however has more than 65% of his resources idle while the steal is seen inside of the VM. Even when placing only a single VM on a hypervisor it still receives steal (0-2%), even though the hypervisor is not overcommited. Hypervisor: 2 Socket system in total 2*28(56HT) cores VM: 30vCPUs (ovirt seems to think its a good idea to make that 15 sockets * 2 cores)

My questions are: a) Could it be that the hypervisor is trying to schedule all 30 cores on a single numa node, ie using the HT cores instead of "real" ones and this shows up as steal? b) Do I need to make VMs this big numa-aware and spread the vm over both numa nodes? c) Would using the High Performance VM type help in this kind of situation? d) General advise: how do I reduce steal in an environment where the hypervisor has idle resources Any advise would be appreciated.