From owner-freebsd-net@FreeBSD.ORG Fri Nov 6 01:41:27 2009 Return-Path: Delivered-To: freebsd-net@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 0C3AD106568D; Fri, 6 Nov 2009 01:41:27 +0000 (UTC) (envelope-from sobomax@FreeBSD.org) Received: from sippysoft.com (gk1.360sip.com [72.236.70.240]) by mx1.freebsd.org (Postfix) with ESMTP id B19A08FC12; Fri, 6 Nov 2009 01:41:26 +0000 (UTC) Received: from [192.168.1.38] (S0106005004e13421.vs.shawcable.net [70.71.167.197]) (authenticated bits=0) by sippysoft.com (8.14.3/8.14.3) with ESMTP id nA61J1Op091788 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 5 Nov 2009 17:19:02 -0800 (PST) (envelope-from sobomax@FreeBSD.org) Message-ID: <4AF3795F.7010103@FreeBSD.org> Date: Thu, 05 Nov 2009 17:18:23 -0800 From: Maxim Sobolev Organization: Sippy Software, Inc. User-Agent: Thunderbird 2.0.0.23 (Windows/20090812) MIME-Version: 1.0 To: stable@FreeBSD.org, freebsd-net@FreeBSD.org Content-Type: text/plain; charset=KOI8-U; format=flowed Content-Transfer-Encoding: 7bit Cc: Subject: em0: watchdog timeout when communicating to windows using 9K MTU X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 06 Nov 2009 01:41:27 -0000 Hi, My em0 interface repeatedly hangs up with watchdog timeout when communicating to the windows host at MTU 9K. [sobomax@pioneer ~]$ grep em0 /var/run/dmesg.boot em0: port 0xecc0-0xecdf mem 0xfe6e0000-0xfe6fffff,0xfe6d9000-0xfe6d9fff irq 21 at device 25.0 on pci0 em0: Using MSI interrupt em0: [FILTER] em0: Ethernet address: 00:22:19:32:87:2f [sobomax@pioneer ~]$ uname -a FreeBSD pioneer.sippysoft.com 7.2-RELEASE-p4 FreeBSD 7.2-RELEASE-p4 #0: Sun Oct 4 03:08:04 PDT 2009 root@pioneer.sippysoft.com:/usr/obj/usr/src/sys/PIONEER amd64 [sobomax@pioneer ~]$ ifconfig em0 em0: flags=8843 metric 0 mtu 9000 options=98 ether 00:22:19:32:87:2f inet 192.168.1.1 netmask 0xffffff00 broadcast 192.168.1.255 inet 192.168.2.1 netmask 0xffffff00 broadcast 192.168.2.255 inet6 fec0::1 prefixlen 64 media: Ethernet autoselect (1000baseTX ) status: active [sobomax@pioneer ~]$ dmesg | grep watchd em0: watchdog timeout -- resetting em0: watchdog timeout -- resetting em0: watchdog timeout -- resetting em0: watchdog timeout -- resetting em0: watchdog timeout -- resetting I have managed to make a packet capture right at the time when hang happens. It appears to be that either "MAC Pause" or "TCP Segment of reassembled PDU" is the last packet that goes through before the interface hangs. Here is the screenshot, if somebody wants to take closer look at the actual packets please let me know. http://sobomax.sippysoft.com/~sobomax/ScreenShot527.png Turning off TSO and TXCSUM/RXCSUM has not helped. Bringing MTU down to 1,500 resolved the problem immediately. I have had the same problem happening several times in the past (although I initially attributed it to the bad cable or something like that), so it's definitely not on-off issue. Given popularity of intel/pro chips in today's computers it look like quite serious issue to me. Any help is greatly appreciated. Regards, -- Maksym Sobolyev Sippy Software, Inc. Internet Telephony (VoIP) Experts T/F: +1-646-651-1110 Web: http://www.sippysoft.com MSN: sales@sippysoft.com Skype: SippySoft