From owner-freebsd-current@FreeBSD.ORG Sun Nov 11 04:11:15 2007 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 4923616A417 for ; Sun, 11 Nov 2007 04:11:13 +0000 (UTC) (envelope-from gwright@antiope.com) Received: from QMTA02.emeryville.ca.mail.comcast.net (qmta02.emeryville.ca.mail.comcast.net [76.96.30.24]) by mx1.freebsd.org (Postfix) with ESMTP id 292D313C4A5 for ; Sun, 11 Nov 2007 04:11:13 +0000 (UTC) (envelope-from gwright@antiope.com) Received: from OMTA08.emeryville.ca.mail.comcast.net ([76.96.30.12]) by QMTA02.emeryville.ca.mail.comcast.net with smtp id BDeB1Y0050FhH240106i00; Sun, 11 Nov 2007 03:59:08 +0000 Received: from [192.168.2.42] ([72.88.201.27]) by OMTA08.emeryville.ca.mail.comcast.net with comcast id BFz71Y0060byEVU0000000; Sun, 11 Nov 2007 03:59:08 +0000 X-Authority-Analysis: v=1.0 c=1 a=LGRm4m9_QTKmN8NkEZYA:9 a=seFGOA53rYDTe6A_figA:7 a=7BqPGlLQWMHFC03kF7osUtdnRKYA:4 a=WuK_CZDBSqoA:10 In-Reply-To: <4735CE3A.7020905@freebsd.org> References: <46B41421-3112-40C6-84D9-094FA771F93E@antiope.com> <4735CE3A.7020905@freebsd.org> Mime-Version: 1.0 (Apple Message framework v752.2) Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Message-Id: Content-Transfer-Encoding: 7bit From: Gregory Wright Date: Sat, 10 Nov 2007 22:59:03 -0500 To: Andre Oppermann X-Mailer: Apple Mail (2.752.2) Cc: freebsd-current@freebsd.org Subject: Re: excessive TCP dulplicate acks revisted 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: Sun, 11 Nov 2007 04:11:15 -0000 On Nov 10, 2007, at 10:28 AM, Andre Oppermann wrote: > Gregory Wright wrote: >> (Note: long message) >> Hi, >> The tcp duplicate ACK attack is back. >> Last March, there was a thread on duplicate TCP acks in -CURRENT. >> I have been able to reproduce the problem on 7.0-BETA2 (amd64) >> and have some new information that might help locate the bug. >> Background: I first noticed problems with tcp connections dropping >> when Bacula was running on our backup server. The hardware was >> a dual Opteron 244, 2 GB RAM, running FreeBSD 6.2-RELEASE-p2. >> The ethernet NIC was a bge. >> We went through an extensive process to rule out hardware and cabling >> problems: the server hardware was replaced with a single Opteron 270 >> (dual core) on a Tyan S2882-D motherboard. The memory was replaced >> as well. The NICs are still bge. This machine is "hardtack". > > This may be a TSO bug in the bge hardware. Please repeat your > tests in > the original setup with TSO disabled on the bge interfaces > ("ifconfig bgeX -tso"). > Second if you've got another network card with something else than bge > please put it into the same box and run the tests as well. > > -- > Andre > Hi Andre, I also took a look at the bge (4) driver in 7.0-BETA2. As far as I can tell, it does not support TSO (there is no ioctl supporting TSO enable/disable as there is for the em(4) driver). Might the chip --- a BCM5704_B0 --- not be completely initialized? This might explain why the machine with the BCM5714_B3 chips works, while the other machine shows the duplicate ACK bug. -Greg