linpack/hpl

Greg Lindahl lindahl at conservativecomputer.com
Tue Sep 25 10:07:57 PDT 2001


On Tue, Sep 25, 2001 at 08:22:41AM -0700, Shane Canon wrote:

> We are adjusting the problem
> size and block size primarily.

You need to set the problem size as large as possible.  If it were too
small, you'd see exactly what you report, namely that above a certain
# of nodes, it begins to suck.

To set the problem size, figure out how much memory per node you want
to use, sum it up, and figure out how big of an array you can then use
(sqrt and divide by the element size, which is double precision
complex, or 16 bytes.)

greg





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