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Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!news.mira.net.au!inquo!in-news.erinet.com!newsfeeder.sdsu.edu!news.sgi.com!olivea!spool.mu.edu!howland.reston.ans.net!EU.net!news.eunet.fi!sja From: sja@tekla.fi (Sakari Jalovaara) Newsgroups: comp.os.linux.networking,comp.unix.bsd.netbsd.misc,comp.unix.bsd.freebsd.misc Subject: Re: TCP latency Date: 25 Jul 1996 09:44:58 GMT Organization: Helsinki University of Technology Lines: 32 Message-ID: <SJA.96Jul25124458@poveri.tekla.fi> References: <4paedl$4bm@engnews2.Eng.Sun.COM> <4sadde$qsv@linux.cs.Helsinki.FI> <31E9E3A7.41C67EA6@dyson.iquest.net> <4sefde$f0l@fido.asd.sgi.com> <4socfr$3ot@dworkin.wustl.edu> <4t63as$f2q@fido.asd.sgi.com> NNTP-Posting-Host: poveri.tekla.fi In-reply-to: lm@neteng.engr.sgi.com's message of 24 Jul 1996 21:07:40 GMT Xref: euryale.cc.adfa.oz.au comp.os.linux.networking:46266 comp.unix.bsd.netbsd.misc:4160 comp.unix.bsd.freebsd.misc:24367 Re "null syscall benchmark" > I'm also willing (and interested) to find a different syscall that just > measures trap overhead, but I haven't seen one yet that I really like. > The getppid() may be the best out there, though, it's hard to cache > that. Thoughts? It seems painfully clear that null syscalls are rather unusual beasts. What is a "null syscall" in one system, isn't in another. A null syscall benchmark seems to reflect precious little real-world program behavior. It is not useful in comparing operating systems or even different versions of the same operating system. Such a benchmark exercises a small portion of a minute detail of an artificially constructed non-real-world program. So, as a thought: as a service to the free OS community, give it up. The flame/usefulness ratio of null syscall benchmarks is damn near infinite. If you are into benchmarking, try to come up with a _useful_ benchmark instead. One that allows people to make a reasoned decision about choosing a particular piece of hardware/software. Such as a disk benchmark (_real_ disk IO - e.g. multiple NNTP servers with a big news hierarchy), network cards (_real_ network traffic under realistic conditions, not a single packet on an unloaded CPU), OS benchmark (behavior of _real_ programs - few people get a system to run null syscalls but many get systems to run databases, graphics, FTP servers, FP computing, interactive multiuser editing/mail reading/ programming, ...) ++sja