[vfio-users] VM Randomly Becomes Choppy

[Ben J]

It seems that CPU usage isn't the issue from further testing. I used
isolcpus to disable cores 0-3, launched the VM with only those cores in use
and each dedicated to one vcpu (used taskset and manually bound each core
to one of the four child processes that had cpu usage), and was still able
to get the same issue to occur. Once the VM slows down it doesn't ever
speed up again without a complete shut down. That's the main thing that
confuses me, it's one thing for the VM to slow down from high resource
usage but it continues lagging even when it's just sitting on the desktop.

It seems to get triggered pretty often by workspace switching and window
movement in BSPWM but that's really the only lead I've got at this point.
The issue still seemed to happen even when I disabled audio altogether.
Anyone have any other ideas?
On Feb 27, 2016 12:36 AM, "Ben J" <btpprograms at gmail.com> wrote:

> I've recently been having issues with my VM's framerate dropping at
> random. It generally boots up completely fine, but at seemingly random
> points it starts to stutter and doesn't stop until the VM is fully turned
> off and back on again. It started out being fairly rare, but now happens on
> almost every launch of the VM after a few minutes.
>
> My specs:
>
> Host OS: Arch Linux
>
> Guest OS: Windows 7
>
> Motherboard: Asus Rampage IV Extreme
>
> CPU: I7-3960X
>
> Graphics: 2X EVGA GTX 580's
>
> My Launch Script:
>
> killall synergys
>
> synergys
>
>
> QEMU_PA_SAMPLES=4096 QEMU_AUDIO_DRV=pa qemu-system-x86_64 -enable-kvm -m
> 4096 -mem-path /dev/hugepages -cpu host,kvm=off \
>
> -smp 6,sockets=1,cores=6,threads=1 \
>
> -bios /usr/share/qemu/bios.bin  -vga none \
>
> -device vfio-pci,host=02:00.0,multifunction=on,x-vga=on \
>
> -device vfio-pci,host=02:00.1 \
>
> -net nic,model=virtio,vlan=0,macaddr=DE:AD:BE:EF:D4:41 \
>
> -net tap,vlan=0,id=network0,ifname=tap0,script=no,downscript=no,vhost=on \
>
> -usb -usbdevice host:046d:c534 -usbdevice host:045e:028e \
>
> -soundhw hda \
>
> -boot menu=on \
>
> -drive file=/dev/sda1,format=raw,if=virtio,cache=none \
>
> -drive
> file=/mnt/LinuxStorage/ISOs/Windows/Drivers/virtio.iso,id=virtiocd,if=none,format=raw
> -device ide-cd,bus=ide.1,drive=virtiocd
>
>
> The issue seems to get triggered immediately whenever I launch a Skype or
> Discord call. It also seems to be more likely when I'm running a game
> within the VM (Tested with Rocket League and Rivals of Aether). It has also
> happened without either of those being open though. I'm really at a loss.
> I've tried disabling huge pages since I suspected that I might not have
> enough, but that showed no difference. Restarting the computer fixes it
> temporarily but it usually happens again shortly after I restart. The same
> thing happens when I suspend and wake up the computer. Has anyone
> experienced this issue before?
>
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