KVM: 0.814
performance: 0.720
vnc: 0.672
debug: 0.636
PID: 0.569
device: 0.564
permissions: 0.557
network: 0.544
other: 0.542
semantic: 0.541
graphic: 0.516
boot: 0.513
socket: 0.484
files: 0.448

High host CPU load and slower guest after upgrade guest OS Windows 10 to ver 1803

After upgrading Windows 10 guest to version 1803, guests VM runs slower and there is high host CPU load even when guest is almost idle. Did not happened with windows 10 up to version 1709.

See my 1st report here:
https://askubuntu.com/questions/1033985/kvm-high-host-cpu-load-after-upgrading-vm-to-windows-10-1803

Another user report is here:
https://lime-technology.com/forums/topic/71479-windows-10-vm-cpu-usage/

Tested on: Ubuntu 16.04 with qemu 2.5.0 and i3-3217U, Arch with qemu 2.12 i5-7200U, Ubuntu 18.04 qemu 2.11.1 AMD FX-4300. All three platform showing the same slowdown and higher host cpu load with windows 10 1803 VM compared to windows 10 1709 VM.

This bug affect me

I ran into similar issues with Windows 10 (1803), with regard to 2D graphics performance.

See my bug report here: https://bugzilla.kernel.org/show_bug.cgi?id=200877

Could you test with Spectre protection (temporarily) turned off inside the Windows VM?

See my post here: https://heiko-sieger.info/low-2d-graphics-benchmark-with-windows-10-1803-kvm-vm/



Hi,
proxmox users have reported this bug
https://forum.proxmox.com/threads/high-cpu-load-for-windows-10-guests-when-idle.44531/#post-213876

hv_synic && hv_stimer  hyperv enlightments fix it


(seem to be related to some hpet change in windows)



----- Mail original -----
De: "Lemos Lemosov" <email address hidden>
À: "qemu-devel" <email address hidden>
Envoyé: Mercredi 1 Août 2018 08:43:46
Objet: [Qemu-devel] [Bug 1775702] Re: High host CPU load and slower guest after upgrade guest OS Windows 10 to ver 1803

This bug affect me 

-- 
You received this bug notification because you are a member of qemu- 
devel-ml, which is subscribed to QEMU. 
https://bugs.launchpad.net/bugs/1775702 

Title: 
High host CPU load and slower guest after upgrade guest OS Windows 10 
to ver 1803 

Status in QEMU: 
New 

Bug description: 
After upgrading Windows 10 guest to version 1803, guests VM runs 
slower and there is high host CPU load even when guest is almost idle. 
Did not happened with windows 10 up to version 1709. 

See my 1st report here: 
https://askubuntu.com/questions/1033985/kvm-high-host-cpu-load-after-upgrading-vm-to-windows-10-1803 

Another user report is here: 
https://lime-technology.com/forums/topic/71479-windows-10-vm-cpu-usage/ 

Tested on: Ubuntu 16.04 with qemu 2.5.0 and i3-3217U, Arch with qemu 
2.12 i5-7200U, Ubuntu 18.04 qemu 2.11.1 AMD FX-4300. All three 
platform showing the same slowdown and higher host cpu load with 
windows 10 1803 VM compared to windows 10 1709 VM. 

To manage notifications about this bug go to: 
https://bugs.launchpad.net/qemu/+bug/1775702/+subscriptions 



hv_synic && hv_stimer only reduces the cpu from 40-50% to 4-5%.
still expecting under 1% like linux guests.

I found that C:\Program Files (x86)\SPICE Guest Tools\drivers\Balloon\w10\amd64/blnsvr.exe intensively requesting something in WMI-provider-host. And there are a lot of errors in event logs about it also.

Gannet, SPICE Guest Tools is certainly a different problem, you should report that to the spice project instead. And since the original problem was apparently fixed via hv_synic / hv_stimer (if I got the comments right), I'm closing this ticket now.