----- Original Message ----- > From: "Peter Krempa" <pkrempa@xxxxxxxxxx> > To: "Francesco Romani" <fromani@xxxxxxxxxx>, libvir-list@xxxxxxxxxx > Sent: Thursday, December 11, 2014 10:04:24 AM > Subject: Re: [PATCH v2] qemu: bulk stats: add pcpu placement information > > On 12/11/14 08:43, Francesco Romani wrote: > > This patch adds the information about the physical cpu > > placement of virtual cpus for bulk stats. > > > > This is the only difference in output with the > > virDomainGetVcpus() API. > > Management software, like oVirt, needs this information > > to properly manage NUMA configurations. > > Are you sure that you are getting what you expect? When this stats group > was first implemented I asked not to include this stat as it only shows > the actual host cpu id where the guest cpu is running at that precise > moment. The problem with that is that usual configurations don't map the > cpus in a 1:1 fashion, but rather allow a specific guest CPU to be run > on a subset of host cpus according to it's scheduling decisions. > > That means that the stat might oscillate in the given set where the > guest vcpu is pinned at. Could you please share your use case for this > one? I'm curious to see whether you have some real use of such data. There is one use case on oVirt on which this very data is used to build a what is claimed to be a Vcpu runtime pinning map. It is used on NUMA flow. I'm not really familiar with that code, and by inspecting it after your answer above, I'm not 100% convinced everything's right in oVirt. I'll need to check more deeply, and I'll reply as soon as I have trustworthy information. Thanks for the insight, -- Francesco Romani RedHat Engineering Virtualization R & D Phone: 8261328 IRC: fromani -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list