*BSD News Article 72612


Return to BSD News archive

Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!news.rmit.EDU.AU!news.unimelb.EDU.AU!munnari.OZ.AU!news.ecn.uoknor.edu!paladin.american.edu!zombie.ncsc.mil!news.mathworks.com!news.PBI.net!cbgw3.att.com!cbgw2.att.com!nntphub.cb.lucent.com!news
From: "John S. Dyson" <dyson@inuxs.att.com>
Newsgroups: comp.os.linux.networking,comp.unix.bsd.netbsd.misc,comp.unix.freebsd.misc
Subject: Re: TCP latency
Date: Thu, 27 Jun 1996 15:36:22 -0500
Organization: Lucent Technologies, Columbus, Ohio
Lines: 28
Message-ID: <31D2F0C6.167EB0E7@inuxs.att.com>
References: <4paedl$4bm@engnews2.Eng.Sun.COM> <4pf7f9$bsf@white.twinsun.com>
		<4qad7d$a5l@verdi.nethelp.no> <4qaui4$o5k@fido.asd.sgi.com> <4qc60n$d8m@verdi.nethelp.no>
NNTP-Posting-Host: dyson.inh.lucent.com
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
X-Mailer: Mozilla 2.0 (X11; I; FreeBSD 2.1-STABLE i386)
Xref: euryale.cc.adfa.oz.au comp.os.linux.networking:43760 comp.unix.bsd.netbsd.misc:3906

Steinar Haug wrote:

> Pentium local           250 usec
> AMD Linux local         330 usec
> AMD FreeBSD local       350 usec
> AMD Linux -> Pentium    420 usec
> AMD FreeBSD -> Pentium  520 usec
> 
> So the difference is quite noticeable. Wish I had another P133 here to
> test with, but unfortunately I don't.
> 
All this TCP latency discussion is interesting, but how does this
significantly impact performance when streaming data through the
connection?  Isn't TCP a streaming protocol?   Was TTCP used in these
tests? I would think that if you were doing that many connections per
second, TTCP would be better generally (like for WWW servers.)
Isn't this just a connection latency?  Hmmm...  Data
througput starts overshadowing connection latency quickly.  Also,
there is some latency that does not really imply CPU usage...

Interesting data point, but really doesn't appear to impact system
performance much if at all.

Isn't meaningless benchmarking fun!!!

John