Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!uunet!mcsun!ukc!slxsys!bae-st!adam From: adam@ste.dyn.bae.co.uk (Adam Curtin) Newsgroups: comp.sys.acorn Subject: Re: C versus ARM Message-ID: <1991Mar7.094220.11685@ste.dyn.bae.co.uk> Date: 7 Mar 91 09:42:20 GMT References: <6397.9103011248@olympus.cs.hull.ac.uk> <5538@acorn.co.uk> Reply-To: adam@ste.dyn.bae.co.uk (Adam Curtin) Distribution: comp Organization: British Aerospace (Dynamics), Stevenage Lines: 34 In article klamer@mi.eltn.utwente.nl (Klamer Schutte -- Universiteit Twente) writes: >PS And a question for the better-informed: When running on a R160 + ARM3 > under RISCiX a sample program without very much floating point did > perform only at 10% of a Sun Sparcstation 1+ (rated 15 MIPS). > The ARM3 should be better than 1.5 (sun) MIPS, isn't he? > Unix overhead is not the answer as the SS1+ did run SunOs 4.1 against > berkely 4.3 for the ARM. Where does the difference come from? I think the main differences are memory and floating point. my old A310 has excellent integer performance and subroutine call/return - on a simple ackerman test it's faster than IBM 6150 (PC/RT) and dumps all over Sun 3/60 and Compaq DeskPro 386/25, while being a good bit slower than a SPARCstation 1 (12.5 MIPS). I'd expect the ARM3 to be within 20% of a 1+ although I don't have access to either of those (just ARM2 (4 MIPS) and SS2 (28MIPS :-)) What really killed the Arc against the big boys toys was floating point performance - the floating point emulator is desperately slow. In fact for fp-intensive programs it's quicker in BASIC (which doesn't use the FPE). The SS1+ has 1.4 MFLOPS where the FPE is best measured in KFLOPS :( Depending on your benchmark, the other areas where I'd put money on the R160 being inferior to the Sun in memory access speed (80ns SIMMs on an SS1+), memory capacity and virtual memory performance - faster disks etc. SunOS 4.1 also has a "tmpfs" file system which is effectively a RAM disk, which peps up compiles a good bit. If any of these points dominate your benchmark, then I can well believe the R160 takes ten times as long as a SPARCstation - fast integer performance isn't everything you know! I don't know why anyone would buy the RiscIx machines, to tell the truth. IN MY OPINION the Sun IPC is a better computer for similar money. Adam -- /home/research/adam/.signature: No such file or directory