On 17/04/18 10:28, Daniel Santos wrote: > On 2018-04-16 23:00, Claudio Jeker wrote: >> On Mon, Apr 16, 2018 at 11:10:46PM +0300, Kapetanakis Giannis wrote: >>> On 16/04/18 18:40, Claudio Jeker wrote: >>> > >>> >>really depends on the KVM/linux version >>> >> >>> >Don't forget to set "options kvm-intel preemption_timer=0" for modprobe on >>> >newer linux kernels. After that it seems to work nicely. >>> > >>> >>> This module option (according to lists) is about timing issues with kvm and >>> obsd. >>> Does it affect performance as well? >> >> It affects stability (sometimes VM hang because the clock interrupts don't >> work correctly) which is a big performace killer. Also for me stat clock >> was not running so there was no way to know what CPU load the VM has. >> >>> which kernel? >> >> I see it for sure on a 4.14 kernel. Guess more affected. > > For me the kernels: > > Host: 3.2.0-4-amd64 Debian Wheezy 7.11 (and no I don't want to upgrade this, > it's running production vms over 300 days). > > Modules: > > kvm_intel 122046 78 > kvm 291951 1 kvm_intel > > I don't use any kvm module options on the Linux host. My host also runs bunch > of other VMs (linuxes with different kernels, freeBSD, windows 7).
That is why I've asked the kernel version from Claudio. I also use Centos7 with kernel 3.10.0-693.21.1.el7.x86_64 on supervisor machines and I don't experience any timing issues or hungs as reported on those threads. Not using any custom modprobe options either. Stability is fine and performance is as it is. G
