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Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!news.cs.su.oz.au!metro!metro!munnari.OZ.AU!news.mel.connect.com.au!news.syd.connect.com.au!phaedrus.kralizec.net.au!news.mel.aone.net.au!grumpy.fl.net.au!news.webspan.net!www.nntp.primenet.com!nntp.primenet.com!su-news-hub1.bbnplanet.com!news.bbnplanet.com!cpk-news-hub1.bbnplanet.com!news.maxwell.syr.edu!news.mathworks.com!uunet!in1.uu.net!204.245.3.50!news.primenet.com!news.primenet.com!not-for-mail From: "Russell L. Carter" <rcarter@consys.com> Newsgroups: comp.unix.bsd.freebsd.misc Subject: Re: FreeBSD slower than Linux ? Date: 31 Jan 1997 09:15:02 -0700 Organization: Conceptual Systems & Software Lines: 37 Message-ID: <32F21A6B.41C67EA6@consys.com> References: <dkleinh.854654600@isotope.ps.uci.edu> X-Posted-By: @207.218.17.187 (eandert) X-Mailer: Mozilla 3.01Gold (X11; U; FreeBSD 2.1-STABLE i386) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Xref: euryale.cc.adfa.oz.au comp.unix.bsd.freebsd.misc:34887 Dirk Kleinhesselink wrote: > > I have been benchmarking a program on various machines and discovered that > the program -- fortran program -- runs 2 to 2.5 times faster on Linux > (Slackware 2.3 - Slackware 96) than on FreeBSD 2.1.5. I have both Linux > and FreeBSD on my Pentium 100 Mhz, 48MB RAM and was pretty surprised. > I'm compiling my program with the stock g77 that comes with each OS. I know > Linux is using gcc-2.7.2 and FreeBSD is using gcc-2.6.3 and so I went back > to my old Slackware 2.3, which has gcc-2.6.3 and this was still twice as > fast. Anyone have any ideas why ? > > Dirk > dkleinh@isotope.ps.uci.edu - I have run probably in excess of 1M lines of fortran code through the f77 interface, and there isn't the slightest bit of difference in the performance of freebsd and linux on a dedicated machine. The performance is also about the best you can expect for the underlying hardware as well. However, g77 is an entirely different beast that the last time I checked absolutely sucked rocks on performance, particularly where there were multiply dimensioned arrays. Why there would be a system difference with g77 I don't know, but if you want performance you probably should try running f77 (f2c->gcc). Also, for most floating point stuff even gcc-pentium doesn't speed things up a lot, and there is not a lot of difference (for nearly all codes) across gcc versions either (options intelligently chosen...) - - Russell L. Carter Voice:(520) 636-2600 FAX:(520) 636-2888 rcarter@consys.com Conceptual Systems & Software, P.O. Box 1129 Chino Valley AZ 86323 "Before sitting down, always look for ferrets."