I'm having this same issue but the 100% cpu spike isn't degrading gameplay somehow, so I don't care for now. Hoping it will be fixed in next kernel update.
On Mon, Mar 21, 2016 at 1:13 PM Jon Panozzo <j...@lime-technology.com> wrote: > Can confirm 4.2.8 kernel doesn’t exhibit this behavior with the same QEMU > package and VM guest. So taking the exact same software configuration to > the 4.2.8 kernel results in normal CPU usage, but with any 4.4.x kernel > variant I’ve tried thus far, I’ve seen the same 100% usage. > > It seems to apply when any media application is in use (3D, audio, or > video). Just playing an MP3 for me caused the host to go to 100%. And if > I leave shadowplay running, it stays at 100% as well. Any application that > pulls on a VFIO passed-through device seems to cause this to occur for me. > > > On Mar 17, 2016, at 3:55 PM, Jon Panozzo <j...@lime-technology.com> > wrote: > > > > Also experiencing this with Linux kernel 4.4.5 and QEMU 2.5.0. Odd > behavior indeed. > > > >> On Feb 14, 2016, at 9:34 PM, globalgorri...@fastmail.fm wrote: > >> > >> Still the same with 4.5-rc4 and AUR qemu-git. > >> > >> On 23 Jan 2016, at 18:55, Dan Ziemba wrote: > >> > >>> On Tue, 2016-01-19 at 16:52 +0100, Friedrich Oslage wrote: > >>>> I did some more testing and it turns out to be a kernel error, > >>>> introduced somewhere around linux 4.3. > >>>> > >>>> Short description of the error: 100% cpu usage while using 3d in a vm > >>>> with vfio > >>>> > >>>> My last known good kernel is 4.2.8, which gives me about 20% cpu > >>>> usage > >>>> while playing Diablo III. My first known bad kernel is 4.3.3, which > >>>> gives me 100% cpu usage with every game, even while idle-ling in the > >>>> menu. > >>>> > >>>> On 01/17/2016 10:29 AM, Friedrich Oslage wrote: > >>>>> my host system is linux-4.4.0 with qemu-2.5.0 and a 4-core i7. > >>>>> Linux is > >>>>> booted with isolcpus=1-3,5-7 to reserve 3 cores + threads for the > >>>>> Windows 10 VM. > >>>>> The VM's 3 cores(2 threads each) are pinned to the respective > >>>>> physical > >>>>> core/thread. The iothread is pinned to 1-3,5-7. > >>> > >>> Interesting, I've also noticed similar behavior since upgrading to > >>> kernel 4.4 and qemu 2.5.0. I am running 4 cores / 8 threads for the VM > >>> and pinned to individual host threads by libvirt, but I didn't boot > >>> with the isolcpus arg. Emulator threads are pinned to the remaining 4 > >>> host threads. > >>> > >>> Host is a i7-5930K, so 6 cores. Guest is running Win 8.1. > >>> > >>> Just sitting at the pause screen in Fallout: New Vegas, I have a single > >>> CPU running at 100% according to both the windows task manager and the > >>> host. The host cpu thread that is at 100% is one of the ones with a > >>> vcpu pinned to it. In the guest, it does appear that the game is the > >>> thing using all the CPU cycles, and the GPU is basically idle at this > >>> time. > >>> > >>> When I was previously running kernel 4.1.15 and qemu 2.4, New Vegas was > >>> never demanding enough to max out any one cpu no matter what I was > >>> doing with the game. Same goes for more demanding games such as GTA V. > >>> > >>> > >>> I upgraded both kernel and qemu at the same time, so I can't say which > >>> caused it. I haven't really noticed much difference in performance. If > >>> anything, it might be slightly better. I seemed to notice less frame > >>> rate drops and stuttering while playing GTA V after the upgrade. > >>> > >>> Dan > >>> > >>> _______________________________________________ > >>> vfio-users mailing list > >>> vfio-users@redhat.com > >>> https://www.redhat.com/mailman/listinfo/vfio-users > >> > >> _______________________________________________ > >> vfio-users mailing list > >> vfio-users@redhat.com > >> https://www.redhat.com/mailman/listinfo/vfio-users > > > > > _______________________________________________ > vfio-users mailing list > vfio-users@redhat.com > https://www.redhat.com/mailman/listinfo/vfio-users >
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