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From: Greg Lindahl (greg.lindahl_at_[hidden])
Date: 2006-11-07 20:39:15


On Tue, Nov 07, 2006 at 05:02:54PM +0000, Miguel Figueiredo Mascarenhas Sousa Filipe wrote:

> if your aplication is on one given node, sharing data is better than
> copying data.

Unless sharing data repeatedly leads you to false sharing and a loss
in performance.

> the MPI model assumes you don't have a "shared memory" system..
> therefore it is "message passing" oriented, and not designed to
> perform optimally on shared memory systems (like SMPs, or numa-CCs).

For many programs with both MPI and shared memory implementations, the
MPI version runs faster on SMPs and numa-CCs. Why? See the previous
paragraph...

-- greg