*BSD News Article 70627


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Newsgroups: gnu.misc.discuss,comp.os.linux.networking,comp.unix.bsd.netbsd.misc
From: schenk@cs.toronto.edu (Eric Schenk)
Subject: Re: TCP latency
X-Nntp-Posting-Host: qew.cs.toronto.edu
Message-ID: <1996Jun11.005452.9233@jarvis.cs.toronto.edu>
References: <1JWBCFZN@wuschel.ibb.schwaben.com> 	<4pa83i$2km@solutions.solon.com> <4pe4fo$7gi@linux.cs.Helsinki.FI> 	<4paedl$4bm@engnews2.Eng.Sun.COM> <4pf7f9$bsf@white.twinsun.com> <6AbFLHBUcsB@khms.westfalen.de>
Date: 11 Jun 96 04:54:52 GMT
Lines: 25
Xref: euryale.cc.adfa.oz.au gnu.misc.discuss:26269 comp.os.linux.networking:41277 comp.unix.bsd.netbsd.misc:3753

kai@khms.westfalen.de (Kai Henningsen) writes:
>Didn't some recent versions of the Linux kernel _also_ have severe  
>problems with Solaris machines?

Well, yes, but no more than any other people where having with Solaris
machines.

>I seem to remember that the conclusion was  
>that the Solaris machines were doing something wrong, but the Linux kernel  
>was changed to work around this anyway.

I tried to work around it, but the work arounds were of limited success.
Mostly I just made the Linux kernel be a lot more careful about when
it chooses to delay ACKs. Currently I generally manage to get performance from
Solaris boxes over a serial link that is about 50-75% of the
link capacity. This is mostly acheived by using a very small MTU
(296). This isn't great but it's a lot better than 5%.
I'm very happy to hear that Sun has issued a fix for these problems.

-- eric

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Eric Schenk                          www: http://www.cs.toronto.edu/~schenk
Department of Computer Science	               email: schenk@cs.toronto.edu
University of Toronto