From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: [ethtool PATCH 2/2] Add RX packet classification interface Date: Mon, 07 Mar 2011 18:28:01 +0000 Message-ID: <1299522481.2522.24.camel@bwh-desktop> References: <20110211010806.23554.98333.stgit@gitlad.jf.intel.com> <20110211011838.23554.3735.stgit@gitlad.jf.intel.com> <1298302841.2608.35.camel@bwh-desktop> <4D642222.6050202@intel.com> <1298939712.2569.43.camel@bwh-desktop> <4D7138EF.7050606@intel.com> <1299513430.2522.9.camel@bwh-desktop> <4D751038.9040804@intel.com> <1299520664.2522.21.camel@bwh-desktop> <4D75225B.3010008@chelsio.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Alexander Duyck , Santwona Behera , "netdev@vger.kernel.org" To: Dimitris Michailidis Return-path: Received: from mail.solarflare.com ([216.237.3.220]:29474 "EHLO exchange.solarflare.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752918Ab1CGS2E (ORCPT ); Mon, 7 Mar 2011 13:28:04 -0500 In-Reply-To: <4D75225B.3010008@chelsio.com> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, 2011-03-07 at 10:22 -0800, Dimitris Michailidis wrote: > Ben Hutchings wrote: > > On Mon, 2011-03-07 at 09:04 -0800, Alexander Duyck wrote: > >> The only time where location really matters is if you are attempting to > >> overwrite an existing rule and I am not sure how that would be handled > >> in ntuple anyway since right now adding additional rules via ntuple for > >> ixgbe just results in duplicate rules being defined. > > > > As I understand it, the location also determines the *priority* for the > > rule. > > This is true, at least for TCAMs. But it's relevant only when multiple > filters would match a packet. People often use non-overlapping filters, for > these adding the filter at any available slot is OK. Right. But ethtool would have to determine that the filter was non- overlapping, before ignoring the location. Also it cannot allow deletion by location if it ever ignores the location on insertion. We should make the location optional at both the command-line and API level, but never ignore it. > > Which is why I wrote that "@fs.@location specifies the index to > > use and must not be ignored." > > > > To support hardware where the filter table is hash-based rather than a > > TCAM, we would need some kind of flag or special value of location that > > means 'wherever'. > > I'd find the 'wherever' option useful for TCAMs too. Maybe even have a few > of those, like 'first available', 'any', and 'last available'. The last one > is quite useful for catch-all rules without requiring one to know the TCAM size. Agreed. Ben. -- Ben Hutchings, Senior Software Engineer, Solarflare Communications Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.