From owner-freebsd-net@FreeBSD.ORG Wed Jul 2 08:48:35 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 E69DD1065678 for ; Wed, 2 Jul 2008 08:48:35 +0000 (UTC) (envelope-from if@xip.at) Received: from chile.gbit.at (ns1.xip.at [193.239.188.99]) by mx1.freebsd.org (Postfix) with ESMTP id 53CB78FC19 for ; Wed, 2 Jul 2008 08:48:34 +0000 (UTC) (envelope-from if@xip.at) Received: (qmail 27995 invoked from network); 2 Jul 2008 10:48:32 +0200 Received: from unknown (HELO filebunker.xip.at) (86.59.10.180) by chile.gbit.at with (DHE-RSA-AES256-SHA encrypted) SMTP; 2 Jul 2008 10:48:32 +0200 Date: Wed, 2 Jul 2008 10:48:32 +0200 (CEST) From: Ingo Flaschberger To: David Kwan In-Reply-To: Message-ID: References: User-Agent: Alpine 1.10 (LFD 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: freebsd-net@freebsd.org Subject: Re: Poor network performance for clients in 100MB to Gigabit environment 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: Wed, 02 Jul 2008 08:48:36 -0000 Dear David, try to enable flow-control at the gig-e switch and freebsd network card. Kind regards, ingo flaschberger geschaeftsleitung --------------------------- netstorage-crossip-flat:fee powered by crossip communications gmbh --------------------------- sebastian kneipp gasse 1 a-1020 wien fix: +43-1-726 15 22-217 fax: +43-1-726 15 22-111 --------------------------- On Tue, 1 Jul 2008, David Kwan wrote: > I have a couple of questions regarding the TCP Stack: > > > > I have a situation with clients on a 100MB network connecting to servers > on a Gigabit network where the client read speeds are very slow from the > FreeBSD server and fast from the Linux server; Write speeds from the > clients to both servers are fast. (Clients on the gigabit network work > fine with blazing read and write speeds). The network traces shows > congestion packets for both servers when doing reads from the clients > (dup acks and retransmissions), but the Linux server seem to handle the > congestion better. ECN is not enabled on the network and I don't see any > congestion windowing or clients window changing. The 100MB/1G switch > > is dropping packets. I double checked the network configuration and > also swapped swithports for the servers to use the others to make sure > the switch configuration are the same, and the Linux always does better > than FreeBSD. Assuming that the network configuration is a constant for > all clients and servers (speed, duplex, and etc...), the only variable > is the servers themselves (Linux and FreeBSD). I have tried a couple of > FreeBSD machines with 6.1 and 7.0 and they exhibit the same problem, > with no luck matching the speed and network utilization of Linux (2 > years old). The read speed test I'm referring is doing transferring of > a 100MB file (cifs, nfs, and ftp), and the Linux server does it > consistently in around 10 sec (line speed) with a constant network > utilization chart, while the FreeBSD servers are magnitudes slower with > erratic network utilization chart. I've attempted to tweak some network > sysctl options on the FreeBSD, and the only ones that helped were > disabling TSO and inflight; which leads me to think that the > inter-packet gap was slightly increased to partially relieve congestion > on the switch; not a long term solution. > > > > My questions are: > > 1. Have you heard of this problem before with 100MB clients to Gigabit > servers? > > 2. Are you aware of any Linux fix/patch in the TCP stack to better > handling congestion than FreeBSD? I'm looking to address this issue in > the FreeBSD, but wondering if the Linux stack did something special that > can help with the FreeBSD performance. > > > > David K. > > > > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" >