Article View: comp.unix.cray
Article #308Re: Determining number of memory banks?
From: Peter Klausler
Date: Wed, 14 Mar 1990 14:25
Date: Wed, 14 Mar 1990 14:25
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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
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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!samsung!zaphod.mps.ohio-state.edu!sunybcs!boulder!pikes!aspen.craycos.com!pmk 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