From owner-freebsd-net@FreeBSD.ORG Mon Jan 21 15:25:53 2008 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 3FDE416A469 for ; Mon, 21 Jan 2008 15:25:53 +0000 (UTC) (envelope-from sascha=freebsd-net=freebsd.org=veyfegdl@holzleiter.name) Received: from serverbitch.de (serverbitch.de [212.227.60.43]) by mx1.freebsd.org (Postfix) with ESMTP id 0892213C506 for ; Mon, 21 Jan 2008 15:25:53 +0000 (UTC) (envelope-from sascha=freebsd-net=freebsd.org=veyfegdl@holzleiter.name) Received: from transfer.telemaxx.gfsrv.net ([85.115.3.230] helo=[192.168.71.190]) by serverbitch.de with esmtpsa (SSLv3:AES256-SHA:256) (Exim) (envelope-from ) id 1JGyFd-000JQ7-Ko for freebsd-net@freebsd.org; Mon, 21 Jan 2008 16:07:53 +0100 From: Sascha Holzleiter To: freebsd-net@freebsd.org Content-Type: text/plain Date: Mon, 21 Jan 2008 16:07:54 +0100 Message-Id: <1200928074.66357.12.camel@dreamland.gameforge.local> Mime-Version: 1.0 X-Mailer: Evolution 2.12.3 FreeBSD GNOME Team Port Content-Transfer-Encoding: 7bit Subject: Network buffer problem 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: Mon, 21 Jan 2008 15:25:53 -0000 Hi, i've bit of an understanding issue with the netstat output which seems to condradict itself a bit. One of our production machines has a moderate network load (24mbit on a 100mbit device) and quite frequently shows a packet loss rate around 2% on peak times. A netstat -s -p ip output looks like this: 1459405058 packets sent from this host 0 packets sent with fabricated ip header 411987593 output packets dropped due to no bufs, etc. So there are a lot of packets dropped due to buffers. But the mbuffer statistic with netstat -m shows no sign of this: 3470/2095/5565 mbufs in use (current/cache/total) 1536/1078/2614/25600 mbuf clusters in use (current/cache/total/max) 1536/145 mbuf+clusters out of packet secondary zone in use (current/cache) 0/0/0/0 4k (page size) jumbo clusters in use (current/cache/total/max) 0/0/0/0 9k jumbo clusters in use (current/cache/total/max) 0/0/0/0 16k jumbo clusters in use (current/cache/total/max) 3939K/2679K/6619K bytes allocated to network (current/cache/total) 0/0/0 requests for mbufs denied (mbufs/clusters/mbuf+clusters) 0/0/0 requests for jumbo clusters denied (4k/9k/16k) 0/7/6656 sfbufs in use (current/peak/max) 0 requests for sfbufs denied 0 requests for sfbufs delayed 0 requests for I/O initiated by sendfile 5646 calls to protocol drain routines There are no mbufs denied ever, the mbuf max is far above the total amount used so i'm a bit at a loss what's the problem here but it seems to be some kind of buffer issue. I already raised kern.ipc.maxsockbuf to 16777216 and the nmbclusters is still at 25600 which seems fine according to the mbuf statistic above. This is on a GENERIC FreeBSD 6.2 system with an em network card at 100mbit. Greetings, Sascha