On Thu, Oct 15, 2009 at 08:45:52PM -0400, Paul Lambert wrote:
I will second this performance observation. After the latest round of
pathces, I too found that my Windows XP VM was performing much faster than
before and consuming much less cpu time. I then observed that my Fe-11 VM
was performing considerably slower. Sure enough, I have checked my hda
for each VM and the Windows was using native IDE and FE-11 was using
virtio. I have now changed my FE-11 hda to IDE. Seems to exhibit much
more pep! So much for paravirtualization.
It sounds like the kvm virtio drivers are not working like they should.
possible a bug in the drivers..
At least Xen PV drivers are faster than emulated IDE, and use less CPU.
-- Pasi
Paul
On Thu, Oct 15, 2009 at 3:50 PM, Dale Bewley<[1]dlbewley lib ucdavis edu>
wrote:
I assumed the virtio block driver to be faster for a kvm guest than ide,
but I'm seeing quite the opposite. Is this expected?
I normally create guests with a wrapper script around virt-install which
creates guests configured to use IDE disks:
f11-db1.xml-<emulator>/usr/bin/qemu-kvm</emulator>
f11-db1.xml:<disk type='file' device='disk'>
f11-db1.xml-<source file='/var/lib/libvirt/images//f11-db1.img'/>
f11-db1.xml-<target dev='hda' bus='ide'/>
f11-db1.xml:</disk>
I am currently creating a guest with the virt-manager wizard which
apparently uses virtio by default:
f11-archivist.xml-<emulator>/usr/bin/qemu-kvm</emulator>
f11-archivist.xml:<disk type='file' device='disk'>
f11-archivist.xml-<source
file='/var/lib/libvirt/images//f11-archivist.img'/>
f11-archivist.xml-<target dev='vda' bus='virtio'/>
f11-archivist.xml:</disk>
The filesystem formatting and installation are going very very slowly.
Host is 2.6.29.6-213.fc11.x86_64 4x quad core. Guests are also fc11
x86_64.
BTW, I've updated to virt-manager-0.7.0-7, libvirt-0.6.2-18,
qemu-kvm-0.10.6-6, and kernel-2.6.30.8-64 just before creating this
guest but have not restarted libvirtd or rebooted the host.
--
Dale Bewley - Unix Administrator - Shields Library - UC Davis
GPG: 0xB098A0F3 0D5A 9AEB 43F4 F84C 7EFD 1753 064D 2583 B098 A0F3
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