From owner-freebsd-current@FreeBSD.ORG Mon Jan 11 23:38:59 2010 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 3B876106566C for ; Mon, 11 Jan 2010 23:38:59 +0000 (UTC) (envelope-from ehrmann@gmail.com) Received: from mxout-07.mxes.net (mxout-07.mxes.net [216.86.168.182]) by mx1.freebsd.org (Postfix) with ESMTP id 102198FC1E for ; Mon, 11 Jan 2010 23:38:58 +0000 (UTC) Received: from [10.0.0.171] (unknown [64.9.237.22]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.mxes.net (Postfix) with ESMTPSA id C486222E257; Mon, 11 Jan 2010 18:38:49 -0500 (EST) Message-ID: <4B4BB679.2060500@gmail.com> Date: Mon, 11 Jan 2010 15:38:33 -0800 From: David Ehrmann User-Agent: Thunderbird 2.0.0.23 (Windows/20090812) MIME-Version: 1.0 To: pyunyh@gmail.com References: <4B40AFFA.6090706@gmail.com> <20100103221630.GV1166@michelle.cdnetworks.com> <4B47B4F6.8030106@gmail.com> <20100109013145.GG18529@michelle.cdnetworks.com> <4B4ACD68.5030907@gmail.com> <20100111203557.GB1228@michelle.cdnetworks.com> In-Reply-To: <20100111203557.GB1228@michelle.cdnetworks.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-current@freebsd.org Subject: Re: vge traffic problem X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 11 Jan 2010 23:38:59 -0000 Pyun YongHyeon wrote: > If receiver drops TX UDP frame sent by vge(4) would you try > disabling TX checksum offloading of vge(4)? If packet drop happens > only with UDP frames it could be checksum offload bug. Does your > controller is VT6130(PCIe)? > First, netstat before and after the test: share2# netstat -I vge0 -d Name Mtu Network Address Ipkts Ierrs Idrop Opkts Oerrs Coll Drop vge0 1500 00:40:63:xx:xx:xx 38940717 0 0 55913584 0 0 0 vge0 1500 10.0.0.0/22 share2 38886994 - - 55898223 - - - share2# netstat -I vge0 -d Name Mtu Network Address Ipkts Ierrs Idrop Opkts Oerrs Coll Drop vge0 1500 00:40:63:xx:xx:xx 38942065 0 0 55914869 0 0 0 vge0 1500 10.0.0.0/22 share2 38888320 - - 55899491 - - - The error counters were uninteresting. Here's what the internal counters said, but they weren't very interesting, either: http://pastebin.com/m20114095 I ran the test, again, and had tcpdump capture the packets (on the host with the vge interface). tcpdump -i vge0 -w dump.cap -K -s 0 host 10.0.1.2 When I opened it up in Wireshark, it's reporting that the outgoing UDP checksums are incorrect; they're always 0x1ae3. That said, maybe the checksums are done in hardware AFTER tcpdump sees them. I set net.inet.udp.checksum to 0. The bad checksums are gone, but I still see dropped packets. It's on the motherboard, probably wired directly to a PCI-E connection, but yes, it is a VT6130.