Subject: Re: FPU Performance on DECstation 5000/125
To: Karl Maftoum <k.maftoum@student.canberra.edu.au>
From: Jonathan Stone <jonathan@DSG.Stanford.EDU>
List: port-pmax
Date: 08/27/1997 04:17:34
On Wed, 27 Aug 1997 20:58:12 +1000 (EST),
Karl Maftoum <k.maftoum@student.canberra.edu.au> wrote:
>Hmm, this is important because the machines are being used for a
>distributed computing experiment (using pvm) to solve mathematical
>models, so the FPU sorta has to work properly! I'll investigate the
>kernel code. BTW there is a BIG difference .. about 6 times on a float
>multiply, how good is the maths library?
There is a simple test you could try:
1. Compile and link a simple FP_intensive program under Ultrix.
(hopeful y a small-memory, FP-intensive FP benchmark.)
2. Time the program under Ultrix (preferably on an
otherwise-unloaded system).
3. Time the same program running on NetBSD
(i.e,. running the Ultrix binary usign Ultrix emulation).
4. Compare results of 2 and 3....
That will determine if it's a library problem or a kernel
problem.