I don't know what halt_poll_ns does, but wouldn't setting it to 0 disable it and is disabling it bad?
So, what does halt_poll_ns do anyways? On 4 April 2016 at 19:17, Okky Hendriansyah <okky....@gmail.com> wrote: > On Mon, Apr 4, 2016 at 8:20 AM, Jayme Howard <g.pr...@gmail.com> wrote: > >> Okay wow, Alex. That made a huge difference immediately. That dropped >> me from 90% to 33% on the main thread, and all the children are below 10%. >> > >> On Sun, Apr 3, 2016 at 8:07 PM, Alex Williamson < >> alex.l.william...@gmail.com> wrote: >> >>> If this is the issue I think it is, the unraid folks bisected this and >>> found the culprit as: >>> >>> aca6ff2 KVM: dynamic halt-polling >>> >>> ( >>> https://github.com/torvalds/linux/commit/aca6ff29c4063a8d467cdee241e6b3bf7dc4a171 >>> ) >>> >>> It seems to be a poor interaction of the halt polling interval vs the >>> timer ticks on win10. You can pick a different polling interval with the >>> kvm module option halt_poll_ns. The default is 500000. It seemed that >>> setting this to 400000 or lower resolves the issue. You can do this via a >>> modprobe entry, 'options kvm halt_poll_ns=400000' or on the kernel command >>> line with kvm.halt_poll_ns=400000. You can also change it dynamically via >>> 'echo 400000 > /sys/module/kvm/parameters/halt_poll_ns' >>> >> > I can also confirm that tuning the halt_poll_ns kvm module parameter on > kernel 4.4.5 drops the host CPU usage! Haven't done any game benchmark but > from listening to music the CPU load is as low as it is on 4.1.20. Although > reducing the value to what Alex (400000) had suggested is probably > sufficient, I'm currently trying out the value of 0 for it just like what > Unraid 6.20 beta 20 changelog had it set on default [1]. Thanks for the > info, Alex. > > [1] > http://dnld.lime-technology.com/beta/unRAIDServer-6.2.0-beta20-x86_64.txt > > Best regards, > Okky Hendriansyah > > _______________________________________________ > vfio-users mailing list > vfio-users@redhat.com > https://www.redhat.com/mailman/listinfo/vfio-users > >
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