From owner-cvs-all@FreeBSD.ORG Wed Sep 20 18:46:47 2006 Return-Path: X-Original-To: cvs-all@freebsd.org Delivered-To: cvs-all@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 06B9616A49E; Wed, 20 Sep 2006 18:46:47 +0000 (UTC) (envelope-from jmg@hydrogen.funkthat.com) Received: from hydrogen.funkthat.com (gate.funkthat.com [69.17.45.168]) by mx1.FreeBSD.org (Postfix) with ESMTP id CFA9843D8C; Wed, 20 Sep 2006 18:46:30 +0000 (GMT) (envelope-from jmg@hydrogen.funkthat.com) Received: from hydrogen.funkthat.com (0vydyc4fpg849qf7@localhost.funkthat.com [127.0.0.1]) by hydrogen.funkthat.com (8.13.6/8.13.3) with ESMTP id k8KIkTfA065076; Wed, 20 Sep 2006 11:46:29 -0700 (PDT) (envelope-from jmg@hydrogen.funkthat.com) Received: (from jmg@localhost) by hydrogen.funkthat.com (8.13.6/8.13.3/Submit) id k8KIkSQk065075; Wed, 20 Sep 2006 11:46:28 -0700 (PDT) (envelope-from jmg) Date: Wed, 20 Sep 2006 11:46:28 -0700 From: John-Mark Gurney To: David Malone Message-ID: <20060920184628.GH23915@funkthat.com> References: <200609182218.k8IMIMUT059300@repoman.freebsd.org> <200609191431.01649.jkim@FreeBSD.org> <20060919190449.GC720@turion.vk2pj.dyndns.org> <200609191535.08184.jkim@FreeBSD.org> <20060920072626.GA738@turion.vk2pj.dyndns.org> <20060920085236.GA58179@walton.maths.tcd.ie> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060920085236.GA58179@walton.maths.tcd.ie> User-Agent: Mutt/1.4.2.1i X-Operating-System: FreeBSD 5.4-RELEASE-p6 i386 X-PGP-Fingerprint: B7 EC EF F8 AE ED A7 31 96 7A 22 B3 D8 56 36 F4 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 Cc: src-committers@freebsd.org, John Baldwin , cvs-all@freebsd.org, cvs-src@freebsd.org, Jung-uk Kim Subject: Re: cvs commit: src/sys/dev/bge if_bge.c X-BeenThere: cvs-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: John-Mark Gurney List-Id: CVS commit messages for the entire tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 20 Sep 2006 18:46:47 -0000 David Malone wrote this message on Wed, Sep 20, 2006 at 09:52 +0100: > (It's interesting to note that as ethernet cards introduce more > features it is getting harder for us to tell what we put on the > wire. With checksum offloading we can no longer trust the checksum. > With VLAN tagging we can't trust the VLAN tag. With TSO we can't > trust the IP ID, TCP sequence number, TCP timestamps, ... We've > seen some interesting things on Linux recently because with TSO the > RTT esitmation for TCP doesn't work at all the way you expect.) That lends itself, to providing additional data w/ the bpf call, and leaving the data passed to the network card as is... that means w/ TSO, bpf will get a 64k or so sized piece of data... Trying to have the bpf injection code do the spliting, etc, is just complicated... The problem w/ doing it this way means that there will be lots of metadata that needs to be added, (such as the mtu that we told the card to break the packets down to) breaking many tools.. -- John-Mark Gurney Voice: +1 415 225 5579 "All that I will do, has been done, All that I have, has not."