Hello, We have been tuning our libvirt hosts and discovered that setting the txqueuelen on vnetX devices to 2500 we can increase the network throughput by a factor of almost 10. On an eth device it can be set by hand/rc.local with the following instructions http://www.cyberciti.biz/faq/gentoo-centos-rhel-debian-fedora-increasing-... . Because vnetX devices are named on a 'first free' basis and they come and go with the guests the rc.local method is not going to work. I think this needs to be done via libvirt or possibly udev, maybe with some kind of hook. Ideally I would like to be able to set this automatically for all vnetX devices when they are created or even better, on a per guest basis.

Thankyou , I should be able to do it with the hooks. I have raised a feature request at BZ809172 Tim Hughes mailto:thughes@thegoldfish.org On 2 April 2012 17:22, Daniel P. Berrange <berrange(a)redhat.com&gt; wrote: > On Mon, Apr 02, 2012 at 05:15:55PM +0100, Tim Hughes wrote: > > Hello, > > > > We have been tuning our libvirt hosts and discovered that setting the > > txqueuelen on vnetX devices to 2500 we can increase the network > throughput > > by a factor of almost 10. On an eth device it can be set by > hand/rc.local > > with the following instructions > > > http://www.cyberciti.biz/faq/gentoo-centos-rhel-debian-fedora-increasing-... > > . Because vnetX devices are named on a 'first free' basis and they come > > and go with the guests the rc.local method is not going to work. I think > > this needs to be done via libvirt or possibly udev, maybe with some > kind of > > hook. Ideally I would like to be able to set this automatically for all > > vnetX devices when they are created or even better, on a per guest > basis. > > You can probably do this with a hook script: > > http://libvirt.org/hooks.html > > Please also file a BZ requesting that this tunable be directly supported > by libvirt. > > Daniel > -- > |: http://berrange.com -o- > http://www.flickr.com/photos/dberrange/ :| > |: http://libvirt.org -o- > http://virt-manager.org :| > |: http://autobuild.org -o- > http://search.cpan.org/~danberr/ :| > |: http://entangle-photo.org -o- > http://live.gnome.org/gtk-vnc :| >