On Mon, Feb 17, 2020 at 09:23:52PM +0800, 王贇 wrote: > FYI, by monitoring locality, we found that the kvm vcpu thread is not > covered by NUMA Balancing, whatever how many maximum period passed, the > counters are not increasing, or very slowly, although inside guest we are > copying memory. > > Later we found such task rarely exit to user space to trigger task > work callbacks, and NUMA Balancing scan depends on that, which help us > realize the importance to enable NUMA Balancing inside guest, with the > correct NUMA topo, a big performance risk I'll say :-P That's a bug in KVM, see: https://lkml.kernel.org/r/20190801143657.785902257@xxxxxxxxxxxxx https://lkml.kernel.org/r/20190801143657.887648487@xxxxxxxxxxxxx ISTR there being newer versions of that patch-set, but I can't seem to find them in a hurry.
