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FishBoneEK

Member

Registered: 2023-09-26

Posts: 57

Windows VM (guest) graphical performance poorer than expected?

I installed a Windows 10 VM on virt-manager, using KVM and QEMU.
I also installed virtio drivers for my Win 10 guest machine (https://github.com/virtio-win/virtio-wi … me-ov-file), and set up the vm options:
[Video] Model: Virtio, 3D Acceleration checked.
[Display] Type: Spice server; Listen Type: None; OpenGL checked.
And an additional "Channel" according to Chris Titus Tech (https://www.youtube.com/watch?v=6KqqNsnkDlQ):
[Channel] Type: unix; Name: org.qemu.guest_agent.0

But the graphical performance inside Windows guest machine still has some way to go to compare to bare metal, it's visibly laggy, and I can see some rectangle areas on the screen not rendering fast enough when I drag the blue selecting rectangle around in Windows desktop. It indeed improved compared to stock setup (QXL, no virtio drivers installed)

Chris Titus said after the tweaks the performance is near bare metal in the vid (if i remember correctly), though...I can actually see some not so obvious lagging-behind rectangles in his vids as well, if it's not some rendering issue on my Linux host.

I recall Win guest running on Win host inside VMWare performs well (haven't tested on my laptop, will test it soon). Also tried Win guest in VMWare on Linux host, also performs well. So is this graphical performance of mine expected, or there's something wrong?

P.S.: I know there's sth like graphical pass through, heard from the Arch wiki and the YouTube vid, but since both the vid and the wiki say it needs extra tweaking, so I'd like to prevent it. Plus if extra tweaking is required to run a Win VM smoothly...I'd rather try VMWare.

System Info:
CPU: AMD Ryzen 5 5500U with Radeon Graphics
GPU: AMD Lucienne (integrated GPU that is, but it runs KDE Wayland smoothly, and some 3D games as well)

Last edited by FishBoneEK (2024-10-09 13:38:24)

cryptearth

Member

Registered: 2024-02-03

Posts: 1,100

Re: Windows VM (guest) graphical performance poorer than expected?

currently 3d opengl acceleration is only supported for linux guests with vulkan in development - for windows use passthru of a physical gpu or stick to 2d

FishBoneEK

Member

Registered: 2023-09-26

Posts: 57

Re: Windows VM (guest) graphical performance poorer than expected?

currently 3d opengl acceleration is only supported for linux guests with vulkan in development - for windows use passthru of a physical gpu or stick to 2d

Well actually the graphic is laggy even on bare Windows desktop, not running other programs or games. I barely installed anything, it's quite a fresh vm installation.

Updated sys info, you can check out if needed.

Last edited by FishBoneEK (2024-10-09 13:04:51)

Head_on_a_Stick

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From: The Wirral

Registered: 2014-02-20

Posts: 8,513

Website

Re: Windows VM (guest) graphical performance poorer than expected?

I've had reasonable performance from Windows 10 guests under QEMU/KVM with just the virtio drivers (no passthrough), even gnome-boxes manages fine IIRC.

This guide suggests enabling "Enlightenments" in Windows should improve performance significantly (section 2.3). I've never tried that myself though.

---

Freedom for Öcalan!

cryptearth

Member

Registered: 2024-02-03

Posts: 1,100

Re: Windows VM (guest) graphical performance poorer than expected?

5500U

according to https://en.wikichip.org/wiki/amd/cores/lucienne that's a 15W chip with a vega7 class iGPU - and as no mention of a dedicated gpu I guess the entire device is only in the 25W class - something in the realm of a 10" netbook
to put it this way: this device only barely has enough power to do any usefull amount of 3D at all (would like to know how far furmark can push it) yet you overwhelm it with running two operating systems in parallel and expect any 3d from the virtualized environment?
as said: the current 3d acceleration of qemu is only supported for linux guest - and only opengl - that's it!
support for vulkan is currently in development - but again for linux only
I recommend destroy that vm and let virt-manager create a new one based on the win10 preset - and keep the gpu stuff as is - this way you should get at least normal 2d desktop performance

tldr: there's neither support for 3d acceleration for windows guests nor is your 15w netbook powerful enough to compensate for it by pushing software rendering via some 200w cpu

FishBoneEK

Member

Registered: 2023-09-26

Posts: 57

Re: Windows VM (guest) graphical performance poorer than expected?

5500U

according to https://en.wikichip.org/wiki/amd/cores/lucienne that's a 15W chip with a vega7 class iGPU - and as no mention of a dedicated gpu I guess the entire device is only in the 25W class - something in the realm of a 10" netbook
to put it this way: this device only barely has enough power to do any usefull amount of 3D at all (would like to know how far furmark can push it) yet you overwhelm it with running two operating systems in parallel and expect any 3d from the virtualized environment?
as said: the current 3d acceleration of qemu is only supported for linux guest - and only opengl - that's it!
support for vulkan is currently in development - but again for linux only
I recommend destroy that vm and let virt-manager create a new one based on the win10 preset - and keep the gpu stuff as is - this way you should get at least normal 2d desktop performance

tldr: there's neither support for 3d acceleration for windows guests nor is your 15w netbook powerful enough to compensate for it by pushing software rendering via some 200w cpu

I told you I haven't installed anything yet, not even games. And I actually don't want to play games in VM, I'd rather play them on Linux host or Windows host. I'm just having some stuff that can't be solved with wine, therefore have to try on Windows VM.

The Windows guest is fresh, from official Win10 iso image, though virt-manager auto-detected the os as win 11 and I chose win 10 instead later. And I tried default graphic setting (QXL, no virtio). Default or virtio, they both didn't perform well under Windows desktop. That is, when no other programs are running in Windows 10 guest, even by toggling the "Start" menu I can see some lagging. Well ofc they probably don't call it "Start" anymore.

I don't think the CPU is the problem? I monitored CPU usage and it didn't went 100%. I know my GPU is a cheap one, but at least it should be able to handle Windows guest desktop? Unless Windows desktop requires 3D acceleration and I misunderstood that part.

Just tried VMWare on Linux host with win 10 guest, much smoother than KVM/QEMU + virt-manager. I didn't even need to tweak it.

Furry test result:
Linux host:

[ Demo Quick Stats ]
- demo                 : FurMark (GL) (built-in: YES)
- renderer             : AMD Radeon Graphics (radeonsi, renoir, LLVM 18.1.8, DRM 3.59, 6.11.2-arch1-1)
- 3D API               : OpenGL 4.6 (Compatibility Profile) Mesa 24.2.4-arch1.1
- resolution           : 1920x1080
- SCORE                : 795
- duration             : 60000 ms (60.005863 sec)
- FPS (min/avg/max)    : 13.000000 / 13.250653 / 15.000000

Windows guest (VMWare):

[ Demo Quick Stats ]
- demo                 : FurMark (GL) (built-in: YES)
- renderer             : SVGA3D; build: RELEASE;  LLVM;
- 3D API               : OpenGL 4.3 (Compatibility Profile) Mesa 23.2.0 (git-fa8bf4e20e)
- resolution           : 1920x1061
- SCORE                : 119
- duration             : 10055 ms
- FPS (min/avg/max)    : 11 / 12 / 13
- GPU 0: VMware SVGA 3D [15AD- 405]

Windows guest (KVM/QEMU virt-manager, virtio):
Only OpenGL 1 supported, cannot test.
So QEMU doesn't support OpenGL acceleration for Win guest, and the win desktop needs higher OpenGL (or some other compatibility) to accelerate?

Last edited by FishBoneEK (2024-10-10 06:30:18)

cryptearth

Member

Registered: 2024-02-03

Posts: 1,100

Re: Windows VM (guest) graphical performance poorer than expected?

again: graphic acceleration is suuport for linux guests only and your el cheapo netbook just doesn't have enough oomph to keep up with a full blown kvm
why is windows desktop crap? because of windows and its crap wddm driver subsystem
vmware like doesn't run a kvm but para-virt - the difference is: a kvm is more like a translation layer running most of the vm on hardware - para-virtualization is full emulation without any hardware acceleration
it's possible that vmware implementation is better than libvirt - but what do you expect from a 15W U-skew netbook?
have a look at the hardware requirenents of windows - it would be difficult to run it properly bare metal on that toy

FishBoneEK

Member

Registered: 2023-09-26

Posts: 57

Re: Windows VM (guest) graphical performance poorer than expected?

OK I get it now, different types of virtualization different outcomes, so for Windows guest I will just stick to VMWare.

it would be difficult to run it properly bare metal on that toy

This laptop is not that powerless? I'm confident that I can run Win 10 host on it smoothly, excluding 3D heavy games in recent years, or heavy duty tasks like video rendering of course.

cryptearth

Member

Registered: 2024-02-03

Posts: 1,100

Re: Windows VM (guest) graphical performance poorer than expected?

well - technical it would work - but with a 15w U-skew with a target clock of just 2.1ghz it won't be fun and not usefull for anything else than light office work