From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zoltan Kiss Subject: Re: Allow controlling NAPI weight of virtual network interfaces (vif) with sysfs Date: Mon, 16 Mar 2015 11:49:11 +0000 Message-ID: <5506C337.30106@linaro.org> References: <55031852.4080606@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ronald Pina Cc: xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.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 >