Xref: utzoo comp.benchmarks:445 comp.unix.internals:2360 Path: utzoo!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!sdd.hp.com!spool.mu.edu!uunet!mcsun!tuvie!nestroy!usenet From: mah@dec1.wu-wien.ac.at (Michael Haberler) Newsgroups: comp.benchmarks,comp.unix.internals Subject: Re: shared memory -- benchmarks, measurements Message-ID: <1991Mar11.171335.23580@nestroy.wu-wien.ac.at> Date: 11 Mar 91 17:13:35 GMT Article-I.D.: nestroy.1991Mar11.171335.23580 References: Sender: usenet@nestroy.wu-wien.ac.at (The Usenet User) Reply-To: mah@nestroy.wu-wien.ac.at Organization: Wirtschaftsuniversitaet Wien Lines: 17 In article , emv@ox.com (Ed Vielmetti) writes: |> |> I'm looking for some guidance on measuring the performance of a system |> which seems to have a lot of contention for a piece of (system V |> style) shared memory. I'd watch for behaviour of programs with several shared memory segmments attached. On some architectures, there's an upper limit on how many segments are actually attached, and if more than that number of segments are used, they are detached and reattached by the kernel on the fly - with page faults and a kernel trap. That can mean a big difference in performance. I could imagine that that limit might be decreased by the use of shared libraries. - michael