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Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!munnari.OZ.AU!news.ecn.uoknor.edu!qns3.qns.net!imci4!newsfeed.internetmci.com!zdc!zdc-e!szdc-e!news From: "John S. Dyson" <toor@dyson.iquest.net> Newsgroups: comp.os.linux.networking,comp.unix.bsd.netbsd.misc,comp.unix.bsd.freebsd.misc Subject: Re: TCP latency Date: Wed, 10 Jul 1996 11:27:14 -0500 Organization: John S. Dyson's home machine Lines: 105 Message-ID: <31E3D9E2.41C67EA6@dyson.iquest.net> References: <4paedl$4bm@engnews2.Eng.Sun.COM> <31DC8EBA.41C67EA6@dyson.iquest.net> <4rqcsk$ff8@fido.asd.sgi.com> <31E106AF.41C67EA6@dyson.iquest.net> <4rvmtf$ven@linux.cs.Helsinki.FI> NNTP-Posting-Host: dyson.iquest.net Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 3.0b5a (X11; I; FreeBSD 2.2-CURRENT i386) Xref: euryale.cc.adfa.oz.au comp.os.linux.networking:44687 comp.unix.bsd.netbsd.misc:3986 comp.unix.bsd.freebsd.misc:23225 Linus Torvalds wrote: > > In article <31E106AF.41C67EA6@dyson.iquest.net>, > John S. Dyson <toor@dyson.iquest.net> wrote: > > > >Linus EQUATED latency with quality. That is where alot of the > >problem was. I had brought up the notion that there are alot > >of other factors associated with quality, and the cheer about > >the no-load latency being so low was kind-of overblown. > > No, Linus did not EQUATE latency with quality. > > Linus equated the _relation_ between latency and throughput with the > _relation_ between quality and quantity. I may have worded it badly, but > you also seem to still think the world is black-and-white. It isn't, and > in BOTH these relations you have to see both sides. > So you admit it... Linus, quit blaming others for YOUR mistakes in communications. It even appears that you are back-peddling. > > If you think quality vs quantity should always look at quality, you're a > very sorry individual. > Linus, you are showing more and more that you have a bad attitude, bringing your opinion that I am a "sorry individual" into this. In fact, I am not a sorry individual, and you don't even know me. I find your attitude to be sometimes offensive and un-professional. > > In fact, my posts tried actively to not mention any specific OS's at > all, and tried to mention the issues without getting too involved with > such details as what OS you're running, or even what _medium_ you're > running (I tried to make you think about latency and throughput on > memory subsystems too, not just TCP or networks: the issues are really > exactly the same). > I think that it is okay to mention OS'es as examples, so what? It is okay to communicate in terms of examples. In fact the original latency discussion was in the terms that Linux is faster than FreeBSD in a rather obscure way (relative to the performance figures that matter to most people using these OSes.) > > In short, I'm NOT attacking BSD for having slower TCP latency: that may > well not even be true under different circumstances. I'll freely admit > that we have our own set of problems with Linux, and we won't just sit > still and be contented with what we have. > Geesh, you are misttating the facts AGAIN!!! You have shown that Linux has faster NO LOAD latency. That is only a small piece of the puzzle. I wonder what the performance figures are for a real world latency number? > What I AM attacking is the > mentality that people show (not only you, John, but you've been arguing > that most) that seems to think that bandwidth is more important than > latency. > You are looking at the argument in a very narrow way -- NO LOAD latency is an interesting figure, but that is ONLY ONE latency figure. > > I'd also like to argue that a "idle" system is not less important than a > "loaded" system. For clients, the idle system tends to be the normal > case, while servers have the loaded behaviour. BOTH are important, and > I find it very very scary indeed that the UNIX community _always_ seems > to think that servers and throughput are somehow "more important" than > clients and latency. > Okay, then state that the Linux NO LOAD latency is faster... Don't say that the Linux networking latency is faster than BSD -- you have shown only one specific circumstantial number to demonstrate your position. One other thing, the numbers show that the DRIVER used on BSD is slower -- the networking code is NOT SHOWN to be slower... Refer to the numbers... Do you know that my localhost results on my P5-166 are 200usecs? That is faster than the Linux measurements that are being espoused as a "record" isn't it??? There is too much hyperbole associated with the issue at hand. I think that there is little integrity in the way that the benchmark results are being touted as "finally showing that Linux is as good as BSD." Even Larry McVoy in other postings has admitted that Linux falls down under load... You back-peddling is showing that you overreached a bit, maybe one day Linux will catch up... Did you know that Dhrystone measures faster numbers on FreeBSD at times? Does that make FreeBSD better.... NOT!!! > > Finally, the discussion may have been a bit one-sided: we've been able > to discuss only the low-load latency, simply because we don't have > numbers for anything else. > Cool, you are seeing my point *finally*, sigh... It is obvious that the latency number being measured is a *specific* case. I am sure that after all of these discussions, someone (who will remain nameless :-)) will be thinking about benchmarking this performance number. BTW, I am making no claims that *BSD will come out better than Linux after that benchmark either. I am saying that the limited latency benchmark being touted as "proof" that the Linux networking code is "faster" is inadequate to make that claim. John