Xref: utzoo comp.parallel:1871 comp.sys.transputer:2186 Path: utzoo!attcan!uunet!cs.utexas.edu!wuarchive!emory!hubcap!robert From: robert@zeus.ee.uwa.oz.au (Roberto Togneri) Newsgroups: comp.parallel,comp.sys.transputer Subject: T800 - how fast is it really? Summary: T800 - how fast is it really? Keywords: transputer IRIS t800 parallel Message-ID: Date: 5 Nov 90 18:20:18 GMT Sender: fpst@hubcap.clemson.edu Organization: Elec Eng, Univ of Western Australia Lines: 26 Approved: parallel@hubcap.clemson.edu Hi, I have been experimenting with our transputers to allow faster execution times to be achieved over our IRIS workstations. The personal IRISes are rated at 10 MIPS and use a MIPS CPU including the floating point unit. The transputers are a mix of t800d and t800c chips (and a T414 root) running at 20 Mhz and I am lead to believe that they can achieve 10 MIPS. With a 10 t800 transputer array then I expect to go at least 7 times faster than the IRISes. Well all I've been able to get is 1.5 times faster! I use the optimiser on the IRIS compiler (cc -O prog.c) and am using 3L parallel C (v2.0) for the transputers (t8c prog.c). Thinking that my program was at fault (parallel programming ain't easy) I ran two similar programs on the IRIS and a t800. And lo! The IRIS was 5 times faster. Is this expected? How fast are the t800's? How good is the compiler? What am I doing wrong? If somebody can shed some light on this I would really appreciate it. -- Dr. Roberto Togneri Dept. of EE Engineering Phone: +61-9-380-2535 The University of Western Australia Fax: +61-9-380-1065 NEDLANDS WA 6009 Email: robert@swanee.ee.uwa.oz.au