Date: Tue, 1 Jun 2004 15:59:23 -0700 From: Brooks Davis <brooks@one-eyed-alien.net> To: Luke <luked@pobox.com> Cc: freebsd-current@freebsd.org Subject: Re: Cap on network speed in CURRENT? Message-ID: <20040601225922.GA20044@Odin.AC.HMC.Edu> In-Reply-To: <Pine.NEB.4.60.0406011524390.20463@otaku.freeshell.org> References: <Pine.NEB.4.60.0406011524390.20463@otaku.freeshell.org>
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[-- Attachment #1 --] On Tue, Jun 01, 2004 at 03:38:18PM -0700, Luke wrote: > > I've got a 100Mbps LAN with ethernet cards that should be capable of using > it, yet the highest transfer rates I seem to be able to get out of my > FreeBSD box are 260KB/s receiving and 341KB/s sending with around 200KB/s > being more normal. > > I realize that there are hundreds of factors that could be influencing > this, but I came across this recent article that made me wonder if this is > some kind of hardcoded limit: > http://www.freebsd.org/news/status/report-jan-2004-feb-2004.html#Automatic-sizing-of-TCP-send-buffers > > Is this article saying that my network speed is limited by a small > static TCP buffer size? If so, is there some way that I can increase that > buffer size to improve performance? The primary function of this machine > is to move large amounts of data across my network, so I'm willing to > experiment with increasing the buffer size if it's not too difficult. On a LAN, buffer size has minimal effect except at very high speeds. Without tuning, two 5.x boxes with gigabit interfaces connected to a Cisco 6513 switch (one 5/10/04 and one 2/20/04) reached 187Mbps in iperf. You're problems symptoms sound like duplex mismatch or bad hardware to me. -- Brooks -- Any statement of the form "X is the one, true Y" is FALSE. PGP fingerprint 655D 519C 26A7 82E7 2529 9BF0 5D8E 8BE9 F238 1AD4 [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (GNU/Linux) iD8DBQFAvQpKXY6L6fI4GtQRAg8uAKDBCZpB6c5rjs7bEtb2irpILJcS5ACfVeLD /bh/RE7DKj6VkSHsOHm3p4o= =RVXA -----END PGP SIGNATURE-----
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