From owner-svn-src-all@FreeBSD.ORG Fri Nov 1 03:22:43 2013 Return-Path: Delivered-To: svn-src-all@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id 76B8BA4D; Fri, 1 Nov 2013 03:22:43 +0000 (UTC) (envelope-from jmg@h2.funkthat.com) Received: from h2.funkthat.com (gate2.funkthat.com [208.87.223.18]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 4DFBD2743; Fri, 1 Nov 2013 03:22:42 +0000 (UTC) Received: from h2.funkthat.com (localhost [127.0.0.1]) by h2.funkthat.com (8.14.3/8.14.3) with ESMTP id rA13Mg3v062564 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 31 Oct 2013 20:22:42 -0700 (PDT) (envelope-from jmg@h2.funkthat.com) Received: (from jmg@localhost) by h2.funkthat.com (8.14.3/8.14.3/Submit) id rA13MgQS062563; Thu, 31 Oct 2013 20:22:42 -0700 (PDT) (envelope-from jmg) Date: Thu, 31 Oct 2013 20:22:42 -0700 From: John-Mark Gurney To: Andre Oppermann Subject: Re: svn commit: r257455 - head/sys/net Message-ID: <20131101032242.GI58155@funkthat.com> References: <201310311546.r9VFkAIb049844@svn.freebsd.org> <20131031180336.GA62132@onelab2.iet.unipi.it> <5272AAC4.4030700@freebsd.org> <1383247645.31172.29.camel@revolution.hippie.lan> <5272D6E0.8050709@freebsd.org> <1383258763.31172.46.camel@revolution.hippie.lan> <5272DCA4.8040209@freebsd.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5272DCA4.8040209@freebsd.org> User-Agent: Mutt/1.4.2.3i X-Operating-System: FreeBSD 7.2-RELEASE i386 X-PGP-Fingerprint: 54BA 873B 6515 3F10 9E88 9322 9CB1 8F74 6D3F A396 X-Files: The truth is out there X-URL: http://resnet.uoregon.edu/~gurney_j/ X-Resume: http://resnet.uoregon.edu/~gurney_j/resume.html X-to-the-FBI-CIA-and-NSA: HI! HOW YA DOIN? can i haz chizburger? X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.2 (h2.funkthat.com [127.0.0.1]); Thu, 31 Oct 2013 20:22:42 -0700 (PDT) Cc: svn-src-head@FreeBSD.org, svn-src-all@FreeBSD.org, src-committers@FreeBSD.org, Luigi Rizzo , Ian Lepore X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 01 Nov 2013 03:22:43 -0000 Andre Oppermann wrote this message on Thu, Oct 31, 2013 at 23:41 +0100: > >I know of only one modern ARM SoC that's able to DMA network packets on > >a 2-byte boundary (actually even it requires a 4-byte boundary, but it's > >willing to stuff the first 16 bits with zeroes and offset everything > >that follows accordingly). I'm sure there are others, but it's the > >exception rather than the rule. > > Talk about foot shooting. I'm afraid that packet copying may still be > the least evil option in the grand scheme of things. IIRC ARM64 will > be able to do misaligned accesses with only a small performance penalty, > like x86/AMD64. LOL. Really? You really want to say that it's fine for embeded systems to loose around half their network performance because we can't make this change? Because we can't be bothered to handle the code the correct way? -- John-Mark Gurney Voice: +1 415 225 5579 "All that I will do, has been done, All that I have, has not."