Seems that for my host specs I should have much better performance than I’m seeing. A vanilla Debian 13 or Ubuntu 24 VMs performance is very bad. Just dragging a window across the screen is very jumpy/laggy. I had better performance in my old 2017 iMac on VirtualBox. I tried VirtualBox on my host as a test and its performance was just as bad.
Is there something I’m missing here?
In the host BIOS I have all of these on:
SVM
IOMMU
SR-IOV
CPPC - Driver
VM Specs:
Debian 13 KDE / Ubuntu 24 KDE
Memory: 10gb
Cores: 8
Chipset: Q35
Firmware: UEFI
Display Spice: Spice Server
Video Virtio: Virtio
3D acceleration: unchecked (VM wouldnt start with it checked)
If you really want good video performance, you might need to do that whole GPU pass-through configuration, but I’ve never messed with it.
Another option that might work depending on what you need would be Distrobox. Again, I’ve never used it personally, but Distrobox should perform much better than KVM.
VirtualBox had slightly lower perf than VMWare Player for a OpenGL game (post), but iirc desktop performance was fine on VirtualBox.
Not sure if I had CPU virt enabled, but graphics seemed ok VirtualBox (I think some built-in VM GPU Mesa thing but don’t recall needing to set anything specific up but maybe a 3D acceleration checkbox); in that case I was just using the VM’s generic GPU translation thing (no experience with direct-GPU/passthrough)
I mostly run Fedora in my VMs nowadays (with Boxes and virt-manager). Can you make sure your VMs have the appropiate agent running (spice-vdagent.service or something along those lines).
If you do, I’d then try to recheck if you can enable acceleration in the VM software, and if not debug that issue. Might also be worth trying out X11 for the VMs (in case they are running wayland).
Currently my main machine is an Ubuntu system and can’t tell if there is a regression with KVM in F43. But in normal operations my experience is seamless (F43 X11 Xfce VMs) and only a 5% CPU penalty for running a VM (measured via Geekbench).
