On Thu, Jun 11, 2020 at 5:10 PM Patrick O'Callaghan <pocallaghan@xxxxxxxxx> wrote: > > On Wed, 2020-06-10 at 16:14 -0700, Gordon Messmer wrote: > > On 6/10/20 9:36 AM, Patrick O'Callaghan wrote: > > > > On 6/10/20 2:56 AM, Patrick O'Callaghan wrote: > > > > > In KVM/QEMU you can also pin specific cores to your VM to prevent > > > > > competition between the host and guest (mainly by avoiding cache > > > > > pollution as I understand it). > > > https://vfio.blogspot.com/2015/05/vfio-gpu-how-to-series-part-4-our-first.html > > > > > > (search for vcpupin partway down the page). This doesn't relate to NUMA > > > systems but to cache efficiency (also mentioned in your second > > > reference), though it may be a matter of terminology. Perhaps I should > > > have said "avoid" or "mitigate" rather than "prevent". > > > > I don't see anything there that suggests that CPU affinity is related to > > competition between the host and the guest. > > It relates to competition in the sense that keeping host and guest to > disjoint sets of cores avoids them competing for the same cores and > hence contaminating the respective caches. That's all I mean. Don't > read too much into it. Clearly the whole set is still being scheduled > by the host system. > > poc The original poster said that they gave the vm 8 cores, how many cores does the underlying host have (cores and hyperthreads). If the underlying host system only has 8 cores/threads then it is going to be pretty hard for the vm to ever get the 8 it needs at one time that it needs to be allowed to run. _______________________________________________ users mailing list -- users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to users-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/users@xxxxxxxxxxxxxxxxxxxxxxx
