Return to BSD News archive
Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!news.mira.net.au!vic.news.telstra.net!act.news.telstra.net!psgrain!iafrica.com!pipex-sa.net!plug.news.pipex.net!pipex!tank.news.pipex.net!pipex!hole.news.pipex.net!pipex!news.be.innet.net!INbe.net!news.nl.innet.net!INnl.net!hunter.premier.net!news-res.gsl.net!news.gsl.net!news.mathworks.com!newsfeed.internetmci.com!in1.uu.net!zdc!zdc-e!szdc-e!news From: "John S. Dyson" <dyson@indy.celebration.net> Newsgroups: comp.os.linux.networking,comp.unix.bsd.netbsd.misc,comp.unix.bsd.freebsd.misc Subject: Re: TCP latency Date: Fri, 12 Jul 1996 15:42:19 -0500 Organization: AT&T Lines: 39 Message-ID: <31E6B8AB.3E6C@indy.celebration.net> References: <4paedl$4bm@engnews2.Eng.Sun.COM> <31E106AF.41C67EA6@dyson.iquest.net> <4rvmtf$ven@linux.cs.Helsinki.FI> <31E3D9E2.41C67EA6@dyson.iquest.net> <4s5bl2$qpg@linux.cs.Helsinki.FI> <31E664EB.167EB0E7@inuxs.att.com> <4s67sk$oa9@fido.asd.sgi.com> Reply-To: dyson@indy.celebration.net NNTP-Posting-Host: n-pc.celebration.net Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 3.0b5a (WinNT; I) Xref: euryale.cc.adfa.oz.au comp.os.linux.networking:45016 comp.unix.bsd.netbsd.misc:4010 comp.unix.bsd.freebsd.misc:23404 Larry McVoy wrote: > > John S. Dyson (dyson@inuxs.att.com) wrote: > : The scalability > : issues on the old Linux context switch didn't come into effect until > : about 20processes did it? > > BS. They degraded exponentially. @ were worse than one. > So have you demonstrated otherwise? You are alluding to the issue that I am concerned about. It is that the no-load latency figures don't consider the potential performance hit of even reasonably large number connections. Also, the lat_tcp benchmark hasn't shown any kind of real world performance that I see that most of the users of FreeBSD are interested in. > : You ARE making progress. > > You're failing the "oh, please don't be insulting" test again John. > Why is it insulting? I feel that the issue of scalability is starting to be understood and acknowleged. He got up to three processes, but it still isn't in the area where TCP scalability issues come in to play. I really don't think that the issue of scalability had been considered before, or why was the three process test even presented? :-). Honestly, even I didn't think that the Linux code would have gotten very slow at three connections to localhost... I wouldn't even think that a primitive TCP package would be affected by three connections (actually six, if you consider both sides.) I think that it is best to put this discussion aside until some benchmarks are run under controlled circumstances, by unbiased parties, and with benchmarks that actually measure something that people generally need. This thing is degrading all the way, bordering on teasing by running a scalability benchmark with three :-) connections... John