[CentOS-virt] Windows Xen VM's have high guest CPU usage and poor performance
pasik at iki.fi
Fri Jan 22 09:22:14 UTC 2010
On Fri, Jan 22, 2010 at 11:20:10AM +0200, Pasi Kärkkäinen wrote:
> On Thu, Jan 21, 2010 at 04:39:31PM -0500, Ryan Pugatch wrote:
> > Pasi Kärkkäinen wrote:
> >> Oh, one more thing.. is it only the guest VM taking cpu time when you
> >> monitor with "xm top"?
> >> Do you have the latest service packs installed in the guest?
> >> Have you tried monitoring the performance from inside the guest, to
> >> figure out what takes cpu time there?
> >> -- Pasi
> > The guest is running XP w/ SP3. It is not just the guest VM taking cpu
> > time. Basically, whatever process I am doing hits 100% cpu usage in
> > Windows. If I open IE, it will use 100% cpu for a bit while it opens.
> > If I try to click on a website, it will do it again. Thus, it is
> > causing a very sluggish session as it keeps pausing. It isn't just IE,
> > it's any program I try to use. This CPU usage is reflected in xm top as
> > both the guest's CPU% will hit 100% as will Dom-0.
> Did you verify from Windows Task Manager you're actually using the GPLPV
> PV drivers/devices?
> How do you use the WinXP guest? Through the VNC console, or by using RDP
> over the network? RDP is recommended, since it's much faster.
> Does WinXP have high IOwait?
> > I have done pretty much everything specified in the Xen Best Practices.
> > In fact, I have dedicated 4GB to Dom-0.
> Dom0 only needs 512 MB - 1024 MB (imho) on a common machine.
Oh, one more thing.. I noticed you had apic=0 in the WinXP config.
Try changing that to 1. Not sure if that helps, but worth trying.
Also, are you running latest CentOS 5.4 with updates on dom0?
If yes, you might want to try Xen 3.4.2 from http://gitco.de/repo/
to see if that makes a difference.
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