[Users] inaccurate timers with ovzkernel-2.6.18-164.11.1.el5.028stab068.3

Dietmar Maurer dietmar at proxmox.com
Tue Mar 9 05:17:21 EST 2010


We run kvm on ovz kernels. But it seems that the latest ovzkernel
has problems with posix timers, so kvm mouse movement in not smooth.
By default kvm uses timer_create() and timer_settime() syscalls.

To show the behavior I use the following command:

 /usr/libexec/qemu-kvm -drive file=ubuntu-9.04-desktop-amd64.iso,if=ide,index=2,media=cdrom -m 512 -net none -clock dynticks

Everything runs normal when I use any other timer option ('rtc' or 'unix'). For example
this works perfectly:

 /usr/libexec/qemu-kvm -drive file=ubuntu-9.04-desktop-amd64.iso,if=ide,index=2,media=cdrom -m 512 -net none -clock unix

I also tested with standard redhat kernel without openvz patches - everything work well there.

We run on debian, but you can also reproduce the bug on RHEL/CENTOS with the packages provided by opennode:

# wget http://opennode.activesys.org/CentOS/5/opennode/x86_64/RPMS/ovzkernel-2.6.18-164.11.1.el5.028stab068.3.x86_64.rpm
# wget http://opennode.activesys.org/CentOS/5/opennode/x86_64/RPMS/kmod-kvm-83-105.asys.22.4.x86_64.rpm
# wget http://opennode.activesys.org/CentOS/5/opennode/x86_64/RPMS/kvm-83-105.asys.22.4.x86_64.rpm

# rpm -i ovzkernel-2.6.18-164.11.1.el5.028stab068.3.x86_64.rpm
# rpm -i kmod-kvm-83-105.asys.22.4.x86_64.rpm
# rpm -i kvm-83-105.asys.22.4.x86_64.rpm

Any ideas whats wrong?

- Dietmar
  
















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