Re: is it possible to set txqueuelen on vnetX devices automatically

[Tim Hughes <thughes@xxxxxxxxxxxxxxx>]

For anyone interested I have managed to get this working using a udev rule

/etc/udev/rules.d/60-vnet.rules

KERNEL=="vnet[0-9]", RUN+="/sbin/ifconfig %k txqueuelen 2500"

On 2 April 2012 18:03, Tim Hughes <thughes@xxxxxxxxxxxxxxx> wrote:

Thankyou , I should be able to do it with the hooks. I have raised a feature request at BZ809172

Tim Hughes
mailto:thughes@xxxxxxxxxxxxxxx

On 2 April 2012 17:22, Daniel P. Berrange <berrange@xxxxxxxxxx> 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-txqueuelen/
> .  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
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