Date: Wed, 2 Jul 2008 10:22:48 +0800 From: Hwa Hing <hwahing@smartteam.net> To: David Kwan <david.kwan@isilon.com> Cc: freebsd-performance@freebsd.org Subject: Re: TCP stack in FreeBSD poor performance in 100MB to Gigabit environment. Message-ID: <486AE678.8050206@smartteam.net> In-Reply-To: <E83E80FC158BCA4F921B1349E38866B802A6DD77@seaxch07.desktop.isilon.com> References: <E83E80FC158BCA4F921B1349E38866B802A6DD77@seaxch07.desktop.isilon.com>
next in thread | previous in thread | raw e-mail | index | archive | help
-----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-----
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?486AE678.8050206>