Poor Performance With KVM and QEMU

secretknowledge · 2025-01-28 03:38:10

Hi! Recently I set up a Windows 11 VM (libvirt + kvm + qemu) on my system, only to see that the performance seemed to be terrible, only slightly improved when I changed the topology of my CPU host pass through. I am using the QXL video model, and have a decently powerful system (Ryzen 5 5800x3d + RTX 4070). Can anyone help? I've been a long time Arch Linux user but am new to KVM.

This most likely doesn't matter but in case it helps:
Memory: 16GB
DE: Hyprland (wayland compositor)
Kernel: Linux Zen 6.12.10
Last update: today

ReDress · 2025-01-28 04:44:38

secretknowledge wrote:

Hi! Recently I set up a Windows 11 VM (libvirt + kvm + qemu) on my system, only to see that the performance seemed to be terrible, only slightly improved when I changed the topology of my CPU host pass through.

Hi,

How did you calibrate in order to conclude that the performance is poor? Is this in comparison to other virtual machine setups? What resources have you allocated to your virtual machine?

secretknowledge · 2025-01-28 21:57:20

Hi! Sorry for the late response

This performance is compared to VMWare Player, using nothing other than the default config. I am allocating 12 vCPUs with a topology of 2 sockets, 3 cores, and 2 threads. I am also giving it 12 GB of memory. One interesting thing I noticed while running the VM is that while moving a window across the screen, an action that causes the VM to lag almost to a standstill, Windows 11 task manager showed 100% CPU usage but btop (on the Linux host) only showed a ~4% increase in CPU usage. Windows also only showed 1 socket for the CPU in Task Manager, even though it should have been 2.

Thank you so much for your help!

edit: grammer and clarity

Last edited by secretknowledge (2025-01-28 21:58:10)

Arch Linux

#1 2025-01-28 03:38:10

Poor Performance With KVM and QEMU

#2 2025-01-28 04:44:38

Re: Poor Performance With KVM and QEMU

#3 2025-01-28 21:57:20

Re: Poor Performance With KVM and QEMU

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