CentOS virt - Jul 2009 - High CPU usage when running a CentOS guest in VirtualBox

Hi,

I am running CentOS 5.3 32bit as a VirtualBox 3.0.0 guest running on Windows XP.

The Windows host CPU usage is constantly at 50% although the CentOS
guest is completely idle (i.e. 0.00 load average).

I know this is a common problem related to the 1000Hz frequency that
the CentOS kernel runs at. With previous versions of CentOS, I used
the kernel-vm package [1] and it solved my problem. However, according
to the README [2] this isn't necessary as of CentOS 5.3 and therefore
these packages are not maintained anymore (the latest released
kernel-vm is 2.6.18-92.1.22).
>From what I understand, as of CentOS 5.3 it is possible to use the
"divider=10 clocksource=acpi_pm" to reduce the frequency to 100Hz. I
tried this setting, and it made no difference at all. I also tried to
install the VirtualBox guest extensions, and still, the host CPU never
goes below 50%.

Is there any way to solve this issue without resorting to a custom kernel build?

Thanks,
Sagi

[1] http://people.centos.org/tru/kernel-vm/
[2] http://people.centos.org/tru/kernel-vm/readme.txt

On Mon, Jul 6, 2009 at 8:31 AM, Sagi Bashari<sagi at boom.org.il>
wrote:
> Hi,
>
> I am running CentOS 5.3 32bit as a VirtualBox 3.0.0 guest running on
Windows XP.
>
> The Windows host CPU usage is constantly at 50% although the CentOS
> guest is completely idle (i.e. 0.00 load average).
>
> I know this is a common problem related to the 1000Hz frequency that
> the CentOS kernel runs at. With previous versions of CentOS, I used
> the kernel-vm package [1] and it solved my problem. However, according
> to the README [2] this isn't necessary as of CentOS 5.3 and therefore
> these packages are not maintained anymore (the latest released
> kernel-vm is 2.6.18-92.1.22).
>
> >From what I understand, as of CentOS 5.3 it is possible to use the
> "divider=10 clocksource=acpi_pm" to reduce the frequency to
100Hz. I
> tried this setting, and it made no difference at all.
This is interesting.  Could you please try installing the regular
2.6.18-92.1.22 kernel and use the "divider=10 clocksource=acpi_pm"
option?  This is the only way to compare the kernel-vm and the distro
kernel.  Currently, the difference you are seeing could be due to the
fact kernel-vm was from 5.2 and the distro one was from 5.3.

Akemi