Replacing the current qemu-kvm in Debian Wheezy (based on kernel 3.2.X) (qemu-kvm_1.0+dfsg-9_amd64.deb) with qemu-kvm_1.0+dfsg-8_amd64.deb gives me the following performance numbers: guest to guest: ~19.1 gbit/s host to guest: ~27.3 gbit/s In other words I think it is safe to say that there is nothing in the current Debian Wheezy kernel preventing KVM from performing exceptionally good. Hopefully the issue with the newest qemu-kvm Debian package gets solved so this will continue also in the future. Debian Squeeze isn't anywhere near Debian Wheezy in virtio/vhost performance for the previously given reasons from the Debian qemu-kvm maintainer. Regards, Hans-Kristian On Mon, Apr 16, 2012 at 13:29, Alexandre DERUMIER <aderumier@xxxxxxxxx> wrote: > > note: > proxmox2 kernel is based on 2.6.32-220.7.1.el6 RHEL6.2 kernel. > + qemu-kvm git. > > > ----- Mail original ----- > > De: "Stefan Pietsch" <stefan.pietsch@xxxxxxxxxxxx> > À: "Hans-Kristian Bakke" <hkbakke@xxxxxxxxx> > Cc: kvm@xxxxxxxxxxxxxxx > Envoyé: Lundi 16 Avril 2012 11:01:16 > Objet: Re: Virtio network performance on Debian > > On 12.04.2012 09:42, Hans-Kristian Bakke wrote: > > Hi > > > > For some reason I am not able to get good network performance using > > virtio/vhost-net on Debian KVM host (perhaps also valid for Ubuntu > > hosts then). > > Disc IO is very good and the guests feels snappy so it doesn't seem > > like there is something really wrong, just something suboptimal with > > the networking. > > [......] > > > I have tried: > > ---------------- > > - Replacing Debian Wheezy with Debian Squeeze (stable, kernel > > 2.6.32-xx) - even worse results > > - Replacing kernel 3.2.0-2-amd64 with vanilla kernel 3.4-rc2 and > > config based on Debians included config - no apparent change > > - Extracted the kernel-config file from Fedora 17 alphas kernel and > > used this to compile a new kernel based on Debian Wheezys kernel > > source - slightly worse results > > - ...in addition to exchanging Debian with Fedora 17 alpha, Proxmox > > 1.9 and 2.0 and ESXi 5 which all have expected network performance > > using virtio. > > > > > > So, I am at a loss here. I does not seem to be kernel config related > > (as using Fedoras config on Debian kernel source didn't do anything > > good) so I think it must be either a kernel patch that red hat kernel > > based distros uses to make virtio/vhost much more efficient or perhaps > > something with Debians qemu-version, bridging or something. > > > I have made some tests with a Debian Squeeze KVM host running with the > Linux Kernel 2.6.39 from backports and the Kernel version 2.6.32-11-pve > from Proxmox. > > (http://download.proxmox.com/debian/dists/squeeze/pve/binary-amd64/pve-kernel-2.6.32-11-pve_2.6.32-66_amd64.deb) > > Network performance between two virtual machines on the same host is > significantly slower with the Debian kernel: > > 2.6.39-bpo.2-amd64 : 1.31 Gbits/sec > 2.6.32-11-pve : 2.20 Gbits/sec > > iperf tests between a virtual machine and the KVM host connected to the > same local bridge interface showed similar results. > > Are there other people who can confirm this? > > > Regards, > Stefan > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > -- > > -- > > > > > Alexandre D erumier > Ingénieur Système > Fixe : 03 20 68 88 90 > Fax : 03 20 68 90 81 > 45 Bvd du Général Leclerc 59100 Roubaix - France > 12 rue Marivaux 75002 Paris - France > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
