From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jiri Pirko Subject: Re: [patch net-next v4 0/4] return offloaded stats as default and expose original sw stats Date: Sun, 19 Jun 2016 12:57:22 +0200 Message-ID: <20160619105722.GA2022@nanopsycho.orion> References: <20160616.172632.1759391103978744570.davem@davemloft.net> <20160617082411.GA1981@nanopsycho.orion> <20160617140512.GB1981@nanopsycho.orion> <57640F2A.7090003@mojatatu.com> <9f8e85ac-3e96-257e-cf7f-e7e793d41cf4@cumulusnetworks.com> <20160617154243.GD1981@nanopsycho.orion> <57642F76.6090403@gmail.com> <20160618080000.GA1989@nanopsycho.orion> <576553A0.2060504@mojatatu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Florian Fainelli , David Ahern , David Miller , 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 To: Jamal Hadi Salim Return-path: Received: from mail-wm0-f67.google.com ([74.125.82.67]:34131 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751512AbcFSK50 (ORCPT ); Sun, 19 Jun 2016 06:57:26 -0400 Received: by mail-wm0-f67.google.com with SMTP id 187so7533150wmz.1 for ; Sun, 19 Jun 2016 03:57:25 -0700 (PDT) Content-Disposition: inline In-Reply-To: <576553A0.2060504@mojatatu.com> Sender: netdev-owner@vger.kernel.org List-ID: Sat, Jun 18, 2016 at 03:58:56PM CEST, jhs@mojatatu.com wrote: >On 16-06-18 04:00 AM, Jiri Pirko wrote: >>Fri, Jun 17, 2016 at 07:12:22PM CEST, f.fainelli@gmail.com wrote: > >>>>Yep. And I believe that for offloaded forwarding, this tools should see >>>>hw counters, as they show what is going on in real. >>> >>>If your NIC is offloading packets today, these tools typically won't see >>>these stats, but ethtool -S likely will report what is going on under >>>the hood. >>> >>>Do we actually need to tell apart SW maintained from HW maintained >>>stats, or at the end all that matters is just, as DaveM pointed out, >>>getting the information, and in the case of an Ethernet switch, return >>>HW stats by default and supplement with SW stats whenever we have them, >>>all in the same namespace? >> > >In general it is extremely useful for debugging to be able to see them >separately. One API to unify them (and that API being netlink) is >the way to go. I dont know if you can ever obsolete ethtool if lots >of other utils are using it - but would be nice. >It is also useful to just get the sum of them - but user space can >take care of that. David A., whatever user space tools that depended >on ethtool should now be able to retrieve them via netlink, no? > >>I believe it is valuable for user to know stats for slow path >>(non-forwarded by ASIC). Also, it's just another rtnl attr. Easy. >> > >So Jiri, I see: >IFLA_SW_STATS64 should that be: IFLA_HW_STATS_LINK_64? >I think IFLA_STATS_LINK_64 should continue to send s/ware stats. Well, we spent a lot of time to think about this. The problem with your approach is that existing apps don't see "real-stats" - hw stats. For example snmp daemon takes IFLA_STATS_LINK_64i, so it has to see HW stats there. In order to not break existing apps, we expose HW stats as default.