[PVE-User] "CPU units" breaks virtio

[Tomasz Chmielewski]

I signaled the issue earlier on kvm-devel list ("strange guest slowness 
after some time" thread), as I wasn't sure where the problem comes from.

When using virtio_net driver, after some time (several hours to several 
days), guest gets slow, pinging it gives almost always ~1000 ms replies etc.
Rebooting the guest doesn't help; the guest is also slow in the 
bootloader, i.e. GRUB - see this video (2 MB), how seconds are subtracted:

http://syneticon.net/kvm/kvm-slowness.ogg


The problem does not show up when using e1000 network driver.


It turns out the problems is not in upstream KVM, but rather with the 
"fairsched" patch to KVM which comes with Proxmox VE.

When using KVM without fairsched patch, my guests run fine with 
virtio_net driver.


Do you have any ideas what can be done about it?


-- 
Tomasz Chmielewski
http://wpkg.org