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#1 2018-09-16 06:24:51

retalak
Member
Registered: 2018-05-19
Posts: 9

QEMU-KVM GPU Passthrough Perfomance Horrible After Guest Restart

Hello,
I am having quite a weird issue with my VM and GPU passthrough. It seems I only get near native performance the first time I boot my guest os. If I shutdown my guest and start it back up, I get much worse GPU performance for some odd reason. The only way I have found to resolve this is by restarting my host.

Host: Arch
Guest: Windows 10 1803 (Also occured on 1709)
Ryzen 1700 @ 3.9GHz
G1 Gaming 1080 for guest
EVGA 770 for host
ASRock x370 Taichi (BIOS V3.70)
16GB DDR4 Corsair Vengeance @ 3066MHz
Samsung EVO 850 500GB for guest
WD Blue M.2 500GB for host
Corsair TX650

XML Pastebin: https://pastebin.com/pfk5s3vN

Using latest official packages for everything.

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#2 2018-09-16 13:09:27

Lone_Wolf
Member
From: Netherlands, Europe
Registered: 2005-10-04
Posts: 11,911

Re: QEMU-KVM GPU Passthrough Perfomance Horrible After Guest Restart

post lspci -knn output please, also /etc/modprobe.d/vfio.conf .

The xml output suggests you use libvirt to manage the VM, is that correct ?

Last edited by Lone_Wolf (2018-09-16 13:09:46)


Disliking systemd intensely, but not satisfied with alternatives so focusing on taming systemd.


(A works at time B)  && (time C > time B ) ≠  (A works at time C)

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#3 2018-09-16 14:53:19

retalak
Member
Registered: 2018-05-19
Posts: 9

Re: QEMU-KVM GPU Passthrough Perfomance Horrible After Guest Restart

Lone_Wolf wrote:

post lspci -knn output please, also /etc/modprobe.d/vfio.conf .

The xml output suggests you use libvirt to manage the VM, is that correct ?

Yes that's correct.

lspci: https://pastebin.com/ThpMCSTg

vfio.conf:

options vfio-pci ids=10de:1b80,10de:10f0

Thank you for your help.

Last edited by retalak (2018-09-16 14:53:42)

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#4 2018-09-24 10:43:00

Lone_Wolf
Member
From: Netherlands, Europe
Registered: 2005-10-04
Posts: 11,911

Re: QEMU-KVM GPU Passthrough Perfomance Horrible After Guest Restart

post the output of the script at https://wiki.archlinux.org/index.php/PC … _are_valid

Also dmesg / journalctl output from first and 2nd start of the VM without a reboot inbetween could help.


Disliking systemd intensely, but not satisfied with alternatives so focusing on taming systemd.


(A works at time B)  && (time C > time B ) ≠  (A works at time C)

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