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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!news.ysu.edu!usenet.ins.cwru.edu!agate!theos.com!riscan.riscan.com!van.istar!van-bc!nntp.portal.ca!cynic.portal.ca!not-for-mail From: curt@cynic.portal.ca (Curt Sampson) Newsgroups: comp.os.linux.networking,comp.unix.bsd.netbsd.misc,comp.unix.bsd.freebsd.misc Subject: Re: TCP latency Date: 5 Jul 1996 12:44:50 -0700 Organization: Internet Portal Services, Inc. Lines: 34 Message-ID: <4rjrbi$eqc@cynic.portal.ca> References: <4paedl$4bm@engnews2.Eng.Sun.COM> <31D2F0C6.167EB0E7@inuxs.att.com> <4rfkje$am5@linux.cs.Helsinki.FI> <31DC8EBA.41C67EA6@dyson.iquest.net> NNTP-Posting-Host: cynic.portal.ca Xref: euryale.cc.adfa.oz.au comp.os.linux.networking:44107 comp.unix.bsd.netbsd.misc:3937 comp.unix.bsd.freebsd.misc:22895 In article <31DC8EBA.41C67EA6@dyson.iquest.net>, John S. Dyson <toor@dyson.iquest.net> wrote: >With many/most web pages being 1-2K, the transfer rate starts to >overcome the latency, doesn't it? No, it doesn't. You have to get beyond about 1-2K that to get past the slow-start behaviour. If you have a 512 byte MSS, and a 1500 byte page, it will come back in three segments. The first segment is sent, and must be acknowledged before the second and third segments are sent, thus adding another RTT. However, T/TCP will make a lot more difference in this case than a few microseconds less latency in the sending and receiving hosts. >I guess FreeBSD-current makes it up by being faster with the fork/execs >done by simple www servers. (About 1.1msecs on a properly configured >P5-166.) Most modern HTTP servers pre-fork all their processes anyway, I should think. >I guess what I am saying is that the results would look more credible >with a real load, where the networking code would be exercised more. This is certainly true. I'd be interested in seeing benchmarks that test these OSs with several dozen connections per second. cjs -- Curt Sampson curt@portal.ca Info at http://www.portal.ca/ Internet Portal Services, Inc. Vancouver, BC (604) 257-9400 De gustibus, aut bene aut nihil.