From: John Roberts <johnr@jhu.edu>
Newsgroups: comp.parallel
Subject: Origin2000 Shared Memory
Date: 5 May 1999 03:40:10 GMT
Organization: HCF - Johns Hopkins University, Baltimore, Maryland, USA
Approved: bigrigg@cs.cmu.edu
Message-Id: <7goeiq$m7i$1@goldenapple.srv.cs.cmu.edu>
Originator: bigrigg@ux6.sp.cs.cmu.edu
Xref: ukc comp.parallel:15555


Hi,

When I run a parallel shared memory (as opposed to MPI) program on an
Origin 2000 how do I specify and determine how many processors I'm
using? 

What is the difference between each of the following? They all seem to
work to some degree.

setenv NUM_THREADS $(THREADS)
setenv OMP_NUM_THREADS $(THREADS)
setenv MPC_NUM_THREADS $(THREADS)

If I run 8 threads, what's to say that all 8 threads aren't time
sharing on the same CPU? If I get 8 CPU's do I have exclusive access
to them, or can other threads time-share with mine? Can my threads be
migrated to other processors? How do I know when this happens?

Thanks!!!

John

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