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, [email protected] 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 >> [email protected] >> https://www.redhat.com/mailman/listinfo/vfio-users > > _______________________________________________ > vfio-users mailing list > [email protected] > https://www.redhat.com/mailman/listinfo/vfio-users _______________________________________________ vfio-users mailing list [email protected] https://www.redhat.com/mailman/listinfo/vfio-users
