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.
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.
Paul
On Thu, Oct 15, 2009 at 3:50 PM, Dale Bewley dlbewley@lib.ucdavis.eduwrote:
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
Fedora-virt mailing list Fedora-virt@redhat.com https://www.redhat.com/mailman/listinfo/fedora-virt
I've installed two F11 guests of the same config other than IDE vs VirtIO disks. I updated them fully, and they are performing at comparable speed.
Perhaps the issue is only with the kernel in the installer image.
-- Dale Bewley - Unix Administrator - Shields Library - UC Davis GPG: 0xB098A0F3 0D5A 9AEB 43F4 F84C 7EFD 1753 064D 2583 B098 A0F3
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 _______________________________________________ Fedora-virt mailing list [2]Fedora-virt@redhat.com [3]https://www.redhat.com/mailman/listinfo/fedora-virtReferences
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On 10/19/2009 08:39 PM, Pasi Kärkkäinen wrote:
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.
WinXp is an exception for kvm virtio drivers. More info at http://www.mail-archive.com/kvm@vger.kernel.org/msg22834.html
-- 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 _______________________________________________ Fedora-virt mailing list [2]Fedora-virt@redhat.com [3]https://www.redhat.com/mailman/listinfo/fedora-virtReferences
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Could it be this?
https://bugzilla.redhat.com/show_bug.cgi?id=509383
There's a simple adjustment you can try in comment 3.
Rich.
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Dale Bewley -
Dor Laor -
Pasi Kärkkäinen -
Paul Lambert -
Richard W.M. Jones