From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: [RFC] New Qlogic 10Gb Ethernet driver for 2.6.28 Date: Tue, 26 Aug 2008 10:36:33 +0100 Message-ID: <20080826093632.GW7908@solarflare.com> References: <48AE8549.6090705@garzik.org> <20080822.024252.193704871.davem@davemloft.net> <20080822174626.GC2551@susedev.qlogic.org> <20080822.144343.231567307.davem@davemloft.net> <20080825170148.GA31059@susedev.qlogic.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: David Miller , jeff@garzik.org, Linux-Driver@qlogic.com, netdev@vger.kernel.org Return-path: Received: from smarthost01.mail.zen.net.uk ([212.23.3.140]:45907 "EHLO smarthost01.mail.zen.net.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750755AbYHZJgj (ORCPT ); Tue, 26 Aug 2008 05:36:39 -0400 Content-Disposition: inline In-Reply-To: <20080825170148.GA31059@susedev.qlogic.org> Sender: netdev-owner@vger.kernel.org List-ID: Ron Mercer wrote: > On Fri, Aug 22, 2008 at 02:43:43PM -0700, David Miller wrote: > > From: Ron Mercer > > Date: Fri, 22 Aug 2008 10:46:26 -0700 > > > > > On Fri, Aug 22, 2008 at 02:42:52AM -0700, David Miller wrote: > > > > I also notice that this driver does not do: > > > > > > > > skb_reserve(skb, NET_IP_ALIGN); > > > > > > > > on RX packets to get the IP headers properly 4-byte aligned aligned > > > > after the ethernet header. > > > > > > The chip currenly has problems with 2-byte aligned receive buffers. > > > It will be fixed in the next turn. > > > > If the chip cannot handle this, you will need to copy into a properly > > aligned buffer. > > > > Otherwise some RISC platforms will take unaligned access traps, which > > run extremely slowly, when 32-bit and larger members of the protocol > > headers are read by the networking stack. > > I see your point. I will add the re-alignment but would like to jump > over it for platforms that don't need it. Is there a list somewhere of > the RISC platforms that take a trap on unaligned accesses? Or better > yet, a list of those that don't? You can use #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS. 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.