From owner-freebsd-current@FreeBSD.ORG Fri Nov 16 00:00:35 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 E625716A417 for ; Fri, 16 Nov 2007 00:00:35 +0000 (UTC) (envelope-from andre@freebsd.org) Received: from c00l3r.networx.ch (c00l3r.networx.ch [62.48.2.2]) by mx1.freebsd.org (Postfix) with ESMTP id 5676513C442 for ; Fri, 16 Nov 2007 00:00:35 +0000 (UTC) (envelope-from andre@freebsd.org) Received: (qmail 66818 invoked from network); 15 Nov 2007 23:34:48 -0000 Received: from c00l3r.networx.ch (HELO [127.0.0.1]) ([62.48.2.2]) (envelope-sender ) by c00l3r.networx.ch (qmail-ldap-1.03) with SMTP for ; 15 Nov 2007 23:34:48 -0000 Message-ID: <473CDDAC.9020503@freebsd.org> Date: Fri, 16 Nov 2007 01:00:44 +0100 From: Andre Oppermann User-Agent: Thunderbird 1.5.0.13 (Windows/20070809) MIME-Version: 1.0 To: Gregory Wright References: <46B41421-3112-40C6-84D9-094FA771F93E@antiope.com> <4735CE3A.7020905@freebsd.org> <473780DB.2040705@freebsd.org> <17995F62-7E9B-42E3-A7FA-30143C704C34@antiope.com> In-Reply-To: <17995F62-7E9B-42E3-A7FA-30143C704C34@antiope.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit 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: Fri, 16 Nov 2007 00:00:36 -0000 Gregory Wright wrote: > > On Nov 11, 2007, at 5:23 PM, Andre Oppermann wrote: > >> Gregory Wright wrote: >>> On Nov 10, 2007, at 10:28 AM, Andre Oppermann wrote: >>>> >>> 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. >> >> Perhaps. Do you see the duplicate ACKs in a tcpdump on both the sender >> and the receiver? If you see it on the sender too, then it must be a >> bug in our network stack or the driver (by requeuing the same packet >> over and over again). >> >> --Andre > > The logs show that the duplicate ACKs are generated only by the > receiver. I suspect a bug in the driver, perhaps the ACK packet > is not being removed from the TX buffer ring. Examining the transmitted > packets should be enough to rule out a network stack problem. Is > there any debugging infrastructure I can use or do I just have to > hack in on my own? We don't have an infrastructure to deal with this kind of driver problems. You have to instrument the driver code to report stuck mbufs. -- Andre