I asked:
>
> We are thinking about buying KAP Fortran and C licences for our Alphas.
> I'd like to get some idea of the benefits of using the KAP preprocessor -
> can anybody provide me with some real-life performance figures or examples
> of speedups using KAP on their code?
I got four replies (thanks everyone), repeated below. Based on these,
it seems KAP is worthwhile only in very specific cases. Maybe we will get
a trial KAP licence to see whether it benefits any of the users here.
From: Peter Stern <peter_at_wiscpg.weizmann.ac.il>
I was just at a local Digital HPC meeting where a Digital rep discussing
software tools started to say about KAP, "We find that in 90% of the cases,
..." and I was about to jump down his throat when he continued,
"KAP has no effect or sometimes even degrades the performance. In the
remaining cases, a 10-20% improvement, sometimes as much as 50% is felt."
Well, we have KAP here and that pretty much sums it up. I haven't been able
to get my users to use it because most have had poor experiences. DXML on
the other hand is a real winner. FOr doing standard BLAS or FFT computations
it yields significant improvements. It is also well documented.
From: Paul Rockwell <rockwell_at_rch.dec.com>
Your mileage may vary, of course, but consider that KAP can also automatically
parallelize code to run on SMP systems...
From: jjl_at_mr.picker.com (John Lucak)
I bought a KAP C license some years ago and have yet to find any
code that benefitted from its application.
From: David Warren <warren_at_atmos.washington.edu>
We have a benchmark mesoscale atmospheric model we run here. On an Alphastation
200/233 KAP for fortran cut our cpu from about 58 minutes to about 37 minutes.
On the real runs (several hours) it has had about the same porportion of time
decrease.
--
Julyan Cartwright Email julyan_at_hp1.uib.es
Computer Centre & NeXTmail julyan_at_obelix.uib.es
Department of Physics WWW http://formentor.uib.es/~julyan
University of the Balearic Islands Tel (+34 71) 172893
07071 Palma de Mallorca, Spain Fax (+34 71) 173426
Received on Mon Mar 04 1996 - 10:45:13 NZDT