From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Ahern Subject: Re: [patch net-next v4 0/4] return offloaded stats as default and expose original sw stats Date: Fri, 17 Jun 2016 07:48:35 -0600 Message-ID: References: <1466066237-7719-1-git-send-email-jiri@resnulli.us> <20160616.172632.1759391103978744570.davem@davemloft.net> <20160617082411.GA1981@nanopsycho.orion> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, nogahf@mellanox.com, idosch@mellanox.com, eladr@mellanox.com, yotamg@mellanox.com, ogerlitz@mellanox.com, roopa@cumulusnetworks.com, nikolay@cumulusnetworks.com, linville@tuxdriver.com, tgraf@suug.ch, gospo@cumulusnetworks.com, sfeldma@gmail.com, sd@queasysnail.net, eranbe@mellanox.com, ast@plumgrid.com, edumazet@google.com, hannes@stressinduktion.org, f.fainelli@gmail.com To: Jiri Pirko , David Miller Return-path: Received: from mail-pa0-f46.google.com ([209.85.220.46]:34015 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932933AbcFQNso (ORCPT ); Fri, 17 Jun 2016 09:48:44 -0400 Received: by mail-pa0-f46.google.com with SMTP id bz2so28867672pad.1 for ; Fri, 17 Jun 2016 06:48:43 -0700 (PDT) In-Reply-To: <20160617082411.GA1981@nanopsycho.orion> Sender: netdev-owner@vger.kernel.org List-ID: On 6/17/16 2:24 AM, Jiri Pirko wrote: > > The problem we try to handle is different, it's about offloaded > forwarded packets which are not seen by kernel. Let me try to draw it :) > > port1 port2 (HW stats are counted here) > \ / > \ / > \ / > --(A)---- ASIC --(B)-- > | > (C) > | > CPU (SW stats are counted here) > > > Now we have couple of flows for TX and RX (direction does not matter here): > > 1) port1->A->ASIC->C->CPU > > For this flow, HW and SW stats are equal. > > 2) port1->A->ASIC->C->CPU->C->ASIC->B->port2 > > For this flow, HW and SW stats are equal. > > 3) port1->A->ASIC->B->port2 > > For this flow, SW stats are 0. > > The purpose of this patchset is to provide facility for user to > find out the difference between flows 1+2 and 3. In other words, user > will be able to see the statistics for his slow-path (through kernel). > > Also, as a default the accumulated stats (HW) will be exposed to user > so the userspace apps can react properly. > You no longer agree with this discussion? http://comments.gmane.org/gmane.linux.network/346740 Essentially netdevice stats show counters for packets punted to the cpu and ethool -S shows h/w stats. This patch set seems to invert that.