From owner-freebsd-performance@FreeBSD.ORG Wed Jul 2 03:09:55 2008 Return-Path: Delivered-To: freebsd-performance@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 861461065685 for ; Wed, 2 Jul 2008 03:09:55 +0000 (UTC) (envelope-from hwahing@smartteam.net) Received: from mozart.smartteam.net (mozart.smartteam.net [202.186.153.96]) by mx1.freebsd.org (Postfix) with ESMTP id 510A68FC1A for ; Wed, 2 Jul 2008 03:09:53 +0000 (UTC) (envelope-from hwahing@smartteam.net) Received: from mozart.smartteam.net (localhost [127.0.0.1]) by mozart.smartteam.net (8.13.8/8.13.8) with ESMTP id m622K30v001186; Wed, 2 Jul 2008 10:20:04 +0800 Received: from [192.168.1.101] ( [60.53.52.153]) by mozart.smartteam.net (Scalix SMTP Relay 11.3.0.11339) via ESMTP; Wed, 02 Jul 2008 10:20:03 +0800 (MYT) Date: Wed, 2 Jul 2008 10:22:48 +0800 From: Hwa Hing To: David Kwan Message-ID: <486AE678.8050206@smartteam.net> In-Reply-To: References: x-scalix-Hops: 1 User-Agent: Thunderbird 2.0.0.14 (X11/20080505) X-Enigmail-Version: 0.95.6 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline Cc: freebsd-performance@freebsd.org Subject: Re: TCP stack in FreeBSD poor performance in 100MB to Gigabit environment. X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 02 Jul 2008 03:09:55 -0000 -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I also had such problem with FreeBSD-7 Stable-SMP with 4 port Intel 1GBit NIC em Driver and with Packet Filter, ALTQ enabled. I tested with iperf from network a to network b. I found freebsd droping packets and the transfer speed in routed mode is only 2 mbit/s compare to linux router which able to forward the traffic at almost full speed. David Kwan wrote: > > > I have a few questions regarding the TCP: > > > > 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 100/1G 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 show 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 > constantly 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 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-performance@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-performance > To unsubscribe, send any mail to "freebsd-performance-unsubscribe@freebsd.org" > -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAkhq5ngACgkQn94C8abtJZqjGQCgguGT6NG4LknjD3El+dnamlBv Z1cAniBSYCJ7n2wi/MpWgRcdVhBWcMVT =6jzX -----END PGP SIGNATURE-----