[libvirt] HELP: after host upgrade to F11, guest runs extremely slow
clalance at redhat.com
Tue May 26 06:49:32 UTC 2009
Gerry Reno wrote:
> Gerry Reno wrote:
>> Gerry Reno wrote:
>>> Daniel P. Berrange wrote:
>>>> On Sat, May 23, 2009 at 03:43:12PM -0400, Gerry Reno wrote:
>>>>> I upgraded the host from F10 to F11 (x86_64) with no issues. Now when I
>>>>> start a F10 (i386) guest it runs very very slow. I also see messages on
>>>>> the guest boot console about "clocksource tsc unstable" and some kernel
>>>>> oops. Once it got far enough to start network I logged in and checked
>>>>> the clocksource and it currently is 'acpi_pm' even though the kernel
>>>>> line says clocksource=pit. The available clocksources are acpi_pm,
>>>>> jiffies, and tsc. I do not see 'pit' in the list. How do I fix this issue?
>>>> If the guest runs 'extrememly' slowly then the most like thing is that
>>>> it has fallen back to using QEMU emulation, instead of KVM hardware
>>>> acceleration. Check the /var/log/libvirt/qemu/$GUEST.log to see if there
>>>> is any mesage about not being able to open /dev/kvm. Also make sure that
>>>> KVM modules are loaded, and that 'virsh capabilities' lists KVM as a valid
>>> Ok, I checked the guest log and it says:
>>> /dev/kvm: no such file or directory.
>>> So how do I make this node? Shouldn't libvirt have made it for us?
>> Ok, once I got both kernel modules loaded, it created the /dev/kvm
>> device and now everything runs fine.
> Well, not quite so fine. If I reboot the machine then the kvm modules
> are no longer loaded. How do I keep these modules loaded?
I'm assuming that you haven't installed qemu from the F-11 packages. If you
install the qemu-system-x86 on F-11, it comes with a file
/etc/sysconfig/modules/kvm.modules. On bootup, any scripts in that directory
are executed, and that command automatically loads the appropriate modules for
you. If you don't want to install the F-11 qemu-system-x86 package for some
reason, you'll have to arrange to do the same with a custom script in that
directory, or just in /etc/rc.d/rc.local.
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