*BSD News Article 71612


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!spool.mu.edu!sgigate.sgi.com!imci3!newsfeed.internetmci.com!news.ac.net!news.cais.net!nntp.uio.no!nntp.uib.no!nntp-bergen.UNINETT.no!nntp-trd.UNINETT.no!not-for-mail
From: sthaug@nethelp.no (Steinar Haug)
Newsgroups: comp.os.linux.networking,comp.unix.bsd.netbsd.misc,comp.unix.freebsd.misc
Subject: Re: TCP latency
Followup-To: comp.os.linux.networking,comp.unix.bsd.netbsd.misc,comp.unix.freebsd.misc
Date: 20 Jun 1996 18:41:27 GMT
Organization: Nethelp Consulting, Trondheim, Norway
Lines: 30
Message-ID: <4qc60n$d8m@verdi.nethelp.no>
References: <4paedl$4bm@engnews2.Eng.Sun.COM> <4pf7f9$bsf@white.twinsun.com>
	<4qad7d$a5l@verdi.nethelp.no> <4qaui4$o5k@fido.asd.sgi.com>
NNTP-Posting-Host: trane.uninett.no
In-reply-to: lm@neteng.engr.sgi.com's message of 20 Jun 1996 07:28:04 GMT
Xref: euryale.cc.adfa.oz.au comp.os.linux.networking:42390 comp.unix.bsd.netbsd.misc:3808

[Larry McVoy]

|   : So what kind of hardware is it?
|   
|   P5@133, ASUS motherboard (I can't remember the model number but it is 
|   the really common one, pipeline burst cache), SMC 100Mbit cards using 
|   the DEC tulip chip (nice job, DEC).
|   
|   It's a pretty cool number since Sun's was the next best at 280 on a pair
|   of Ultrasparcs - CPUs that have about 2x the integer perf of the P5s.
|   I would imagine that Linux on the ultras would get that number down to 
|   about a 140 usecs or so round trip.

I see similar effects here. Tried a test varying only *one* side. A P133
running FreeBSD 2.2-960501-SNAP, against an AMD 5x86-133 overclocked to
160 MHz, running either Linux 2.0.0 or FreeBSD 2.2-960612-SNAP. 21140
card at both ends, but running at 10 Mbit/s not 100 (might try the 100
Mbit/s a bit later tonight). The numbers I got with lat_tcp (I assume
that's the one you used :-) were:

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.

Steinar Haug, Nethelp consulting, sthaug@nethelp.no