Subject: cache size affecting G94 calcs

From: [email-masked] (Joseph W. Bausch)
Date: Wed, 27 Aug 1997 02:46:41 -0500

With the help of some on the ccl, I (well, my students!) have succeeded in
getting G94 up and running on a DualPentiumPro operating with linux.  For
those of you out there that may be thinking about going this route with the
cheapness of the pentiums these day, it isn't too hard to set up and get
going, and this was my groups first attempt at setting up a linux box from
scratch.  It is nice to see that the speed with which this machine runs the
seven G94 test jobs frequently quoted in this group is pretty impressive.
However, on the few calculations that I have done of interest to me, it
seems the performance of my system drops significantly when a larger
molecule is calculated.  I base this on the same calcs I do on an rs6000,
which run much faster.  However, on the seven G94 test jobs, this linux box
is faster than the rs6000.  So I am curious as the reason for this, and
wonder if anyone out there running G94 on a PentiumPro running linux has
noticed the same thing.  Is there any solutions to this problem?  Is it
related to having a 256K L2 cache on the Pentium?  Would performance
increase dramatically with a 512K cache?

(Note:  I am giving these jobs plenty of memory and according to the top
command, they are getting full cpu power on the linux box, with little or
no swapping going on).

Thanks in advance (and I'll summarize if there is suitable interest),
Joe
[email-masked]
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