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From: pmk@craycos.com (Peter Klausler)
Newsgroups: comp.unix.cray
Subject: Re: Determining number of memory banks?
Message-ID: <1990Mar14.142536.5973@craycos.com>
Date: 14 Mar 90 14:25:36 GMT
Organization: Cray Computer Corporation
Lines: 25


	parameter (l=11,lp=2048,n=640,nn=n*lp)
	integer m (nn), cps (0:l), str
	str = 1
	do 1 i=0,l
	   j = irtc ()
	   do 2 k=1,n
 2	      m (k*str) = m (k*str) + 1
	   cps (i) = irtc () - j
 1	   str = 2*str
	print 3, (i, cps (i), i=0,l)
 3	   format ('2**',i2,': ',i6,:)
	end

Run this, examine the output, and find the least power of two with the
worst performance (highest clock count). This should give you a pretty
good idea of the number of banks on the machine. On a multiprocessor this
code will yield different results on each run, but at the stride that
equals the bank count things won't differ by too much.

You can also run the 'target' command (on COS or UNICOS) to see what the
compilers and libraries are supposed to believe about the machine; it's usually
trustworthy.

-Peter Klausler @ Cray Computer Corp. in Colorado Springs, CO