Date: Sat, 29 May 1999 11:15:41 -0400 (EDT) From: David Gilbert <dgilbert@velocet.ca> To: Garrett Wollman <wollman@khavrinen.lcs.mit.edu> Cc: David Gilbert <dgilbert@velocet.ca>, freebsd-net@FreeBSD.ORG Subject: Linux and Solaris tcp beating FreeBSD 4:1 Message-ID: <14160.1181.137755.84641@trooper.velocet.ca> In-Reply-To: <199905290250.WAA24826@khavrinen.lcs.mit.edu> References: <14159.19240.129931.14715@trooper.velocet.ca> <199905290250.WAA24826@khavrinen.lcs.mit.edu>
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>>>>> "Garrett" == Garrett Wollman <wollman@khavrinen.lcs.mit.edu> writes: Garrett> <<On Fri, 28 May 1999 22:04:24 -0400 (EDT), David Gilbert Garrett> <dgilbert@velocet.ca> said: >> I havn't done a packet dump yet... but why is Linux beating FreeBSD >> 4:1 and what can I do about it? Garrett> The TCP retransmit timer is initialized to min(2, srtt + Garrett> 4*rttvar). If your link is lossy, you'll probably be in Garrett> retransmit a lot. Unfortunately, the TCP timers in -current Garrett> are measured in 1/2-second intervals (a remnant from the VAX Garrett> implementation), which means that the minimum retransmit Garrett> timeout in FreeBSD is one second. This is probably an order Garrett> of magnitude greater than the round-trip time. Linux and Garrett> Solaris use different TCP timer implementations which have Garrett> much higher-resolution timers. Since the real solution for this is some time in the future, what can I hack on quickly? If I can't change the timeout speed, can I change some other parameter that will help here? I'm taking a lot of flack that netcat port forwarding on a Sparc 1+ can beat our FreeBSD K6-2/400 Dave. -- ============================================================================ |David Gilbert, Velocet Communications. | Two things can only be | |Mail: dgilbert@velocet.net | equal if and only if they | |http://www.velocet.net/~dgilbert | are precisely opposite. | =========================================================GLO================ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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