Re: Allow controlling NAPI weight of virtual network interfaces (vif) with sysfs

[Zoltan Kiss <zoltan.kiss@linaro.org>]

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
>