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Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!nntp.coast.net!lll-winken.llnl.gov!hookup!news.mathworks.com!enews.sgi.com!fido.asd.sgi.com!neteng!lm From: lm@neteng.engr.sgi.com (Larry McVoy) Newsgroups: comp.os.linux.networking,comp.unix.bsd.netbsd.misc,comp.unix.bsd.freebsd.misc Subject: Re: TCP latency Followup-To: comp.os.linux.networking,comp.unix.bsd.netbsd.misc,comp.unix.bsd.freebsd.misc Date: 15 Jul 1996 22:06:38 GMT Organization: Silicon Graphics Inc., Mountain View, CA Lines: 53 Message-ID: <4sefde$f0l@fido.asd.sgi.com> References: <4paedl$4bm@engnews2.Eng.Sun.COM> <31E7C0DD.41C67EA6@dyson.iquest.net> <4s8tcn$jsh@fido.asd.sgi.com> <31E80ACA.167EB0E7@dyson.iquest.net> <4sadde$qsv@linux.cs.Helsinki.FI> <31E9E3A7.41C67EA6@dyson.iquest.net> Reply-To: lm@slovax.engr.sgi.com NNTP-Posting-Host: neteng.engr.sgi.com X-Newsreader: TIN [version 1.2 PL2] Xref: euryale.cc.adfa.oz.au comp.os.linux.networking:45338 comp.unix.bsd.netbsd.misc:4063 comp.unix.bsd.freebsd.misc:23676 John S. Dyson (toor@dyson.iquest.net) wrote: : We could have special cased it to make the benchmark look better, but : we did not. We have looked at it carefully, and it has little impact : on real-world performance. Historically, a NULL syscall is not : a write to /dev/null... That is what the benchmark is, and simply : it is NOT IMPORTANT. Umm, I'd be happy to entertain suggestions for a better measurement of a null entry into the system. I don't want something that anyone special cases - that's just worthless. I want something that is actually measuring all the work you need to do to get to the point that you can do something in the kernel. People typically use getpid() for this, but that is a bummer because of . it is a read only call, you could actualy cache the pid is user space and not go into the kernel at all. . it is very high level, you haven't broken into either the FS layer or the networking layer. Maybe gettimeofday() would have been a better null syscall, what do you think? : > YOU'RE LYING : > : Look, jerk, you are continuing your : stupid, infantile attack on me and FreeBSD. I really don't care about : what you think. Secondly yours is the only response that made this : allegation like you have. YOU ARE ALONE... Well, I doubt you'll buy it, but I agree with Linus that your message certainly implied that Linux special cased the null syscal metric used in lmbench. IF that was your intended implication, you may not have been lying, but you certainly were implying something that simply isn't true. ALL of Linux' syscalls are typically less cost than the typical Unix counterparts. Linus did a nice job with that, you might want to go look at it. : Linus, you are an arrogant, self-righteous a**hole... Umm, when it gets to this level, maybe it is better to give yourself a day or two before you hit that send button. Do you really want to make public statements like this? Seems a little extreme to me. : I DEMAND A PUBLIC RETRACTION. ADDITIONALLY, I DEMAND A FORMAL : WRITTEN APOLOGY or PROOF OF A FORGED USENET POSTING. If you don't : it will be a further demonstration of your ill-will, condescending : behavior, or mean spiritedness. Sheesh. -- --- Larry McVoy lm@sgi.com http://reality.sgi.com/lm (415) 933-1804