Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!uflorida!stat!stat.fsu.edu!mccalpin From: mccalpin@masig1.ocean.fsu.edu (John D. McCalpin) Newsgroups: comp.sys.next Subject: Re: floating-point performance Message-ID: Date: 31 Jul 89 14:34:12 GMT References: <68105@yale-celray.yale.UUCP> Sender: news@stat.fsu.edu Distribution: usa Organization: Supercomputer Computations Research Institute Lines: 55 In-reply-to: blenko-tom@CS.YALE.EDU's message of 30 Jul 89 23:10:05 GMT In the first referenced article above, I posted some floating-poing performance results for the NeXT. In the second article referenced above, Tom Blenko (blenko-tom@cs.yale.edu) made some replies. me>|The C results below were compiled on the NeXT with the standard (GNU) me>|compiler. The Sun results used Sun's (ugh) compiler. tom>So are you comparing compilers with compilers? Most of my results are comparing hardware with hardware, since the same f77 compiler was used. I will post the equivalent numbers for the Absoft f77 compiler when they become available. I used the default C compiler's on each machine. If Sun chooses to ship a crummy compiler, that is not my problem. I do expect Gnu C to do better on the Sun, but I do not think that it is installed on any of the machines that I have access to. me>|I also have a "favorite" benchmark code from one of my applications. me>|A small excerpt of my results shows for 32-bit Fortran (except the Cray): me>| seconds ratio to MicroVAX me>| NeXT 158.4 1.23 me>| Sun 3/280 (fpa) 55.3 3.53 me>| Sun 3/280 (68881) 275.2 0.71 tom>Sun+GnuCC would be more interesting. And how do disk speeds compare? (1) Sun+GnuCC would not have told me anything about the f77 performance of the two machines. The overwhelming majority of number-crunching codes are still written in FORTRAN. (2) The disk speeds are not a noticeable factor in the above comparison. Less than 10% of the time is spent doing I/O, and most of that is spent formatting the output. me>|So for a cheap machine with a 68882 coprocessor, the NeXT does quite me>|well - especially in C. Of course, if you really want to crunch, the me>|DECstation 3100 has MUCH better floating-point performance for only a me>|few thousand more $$$. tom>If you are a university making a major purchase (75 nodes or more, tom>so I hear), you should be able to get a DECStation or a SparcStation tom>with 8Mb, B&W, 100M local disk for under $5K (I know of three tom>universities that have done just this). Which means you can get tom>much better FP performance for significantly less money. Yet another tom>reason why I say a NeXT should cost about $4K. The heavily discounted prices that I have seen on DECstation 3100's still place them at over $10K (with 19" monochrome monitor, 8MB RAM and a 330 MB disk). I don't know about the discounted SparcStation prices, but its floating-point performance is not competitive. -- John D. McCalpin - mccalpin@masig1.ocean.fsu.edu - mccalpin@nu.cs.fsu.edu mccalpin@delocn.udel.edu