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Re: [Xen-devel] Allow controlling NAPI weight of virtual network interfaces (vif) with sysfs



Hi,

In that case I recommend you to take a look at the debugfs patch already in there, based on that it should be pretty straightforward to do it what you want:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=f51de243

It already prints out "queue->napi.weight"

Zoltan

On 13/03/15 19:05, Ronald Pina wrote:
Hi Zoltan

Yes , i successfully achieved good results using tc tools, it could do
the job and the performance was great. But my primary goal is to make
a study about the  of performance impact of  the weight parameter.

It must be noted that Xen use NAPI, and on dom0 every vif is treated
in the same way as every real network interface. On old kernels that
feature was present , here is a patch that can show how was that
implemented:

http://marc.info/?l=linux-netdev&m=111773621018096&w=2

As soon as on later kernel the weight was inserted on napi_struct, the
weight wasn't exposed any more for every interface.
Maybe that feature is not essential necessary, it can be valuable on
dom0 where there many vif . It is another supplementary control knob,
someone may found it useful to tweak the performance.

Regards,
Ronald


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