From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: [PATCH 1/2] net: Toeplitz library functions Date: Tue, 24 Sep 2013 18:02:23 +0100 Message-ID: <1380042143.2736.48.camel@bwh-desktop.uk.level5networks.com> References: <1379980991.3165.37.camel@edumazet-glaptop> <20130924023038.GA22393@order.stressinduktion.org> <20130924033505.GB22393@order.stressinduktion.org> <1380001118.3165.41.camel@edumazet-glaptop> <20130924160145.GB26769@order.stressinduktion.org> <1380039299.3165.91.camel@edumazet-glaptop> <1380041185.3165.97.camel@edumazet-glaptop> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Tom Herbert , Hannes Frederic Sowa , David Miller , "Linux Netdev List" , "Brandeburg, Jesse" To: Eric Dumazet Return-path: Received: from webmail.solarflare.com ([12.187.104.25]:47352 "EHLO webmail.solarflare.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753591Ab3IXRC1 (ORCPT ); Tue, 24 Sep 2013 13:02:27 -0400 In-Reply-To: <1380041185.3165.97.camel@edumazet-glaptop> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, 2013-09-24 at 09:46 -0700, Eric Dumazet wrote: > On Tue, 2013-09-24 at 09:35 -0700, Tom Herbert wrote: > > > We should really be using rxhash for that anyway, eliminate this > > ehashfn. This would entail adding rxhash argument in the various > > udp_lookup functions. > > Nope : Some NICs provide UDP rxhash only using L3 (source IP, > destination IP), not L4 (adding source & destination ports) Indeed the Microsoft RSS spec doesn't define an L4 hash for UDP/IP, since it can't work with fragmented datagrams (which TCP avoids). Using the TCP/IP hash function for UDP is a non-standard option - presumably useful where no fragmentation is expected. Ben. > This is again a case where we want our own hashing. -- Ben Hutchings, Staff Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.