[Beowulf] 1 multicore machine cluster

[Douglas Eadline]

This is an interesting question. As multi-core become more
pervasive this will beg the bigger question. What is cluster?
Recall, there is a design called a "constellation" where the
number of cores on the nodes is greater than the number of nodes.
Therefore if you have four 8-core nodes (32 cores total)
connected with IB, you have a "constellation cluster".
The "parallelism" may be more in the nodes, than between
the nodes.

In any case, you have a pile of cores how do you program
them? Fortunately MPI will work on multi-core and across nodes.
For the most part, OpenMP and threads only work on single
motherboards. I investigated this idea (MPI vs OpenMP on
a single multi-core node) and wrote up my results here:

  http://www.linux-mag.com/id/4608

Of course, there is a need for more testing
with different compilers and hardware platforms,
but it is clear, MPI on multi-core SMP is not
necessarily a bad idea, in some cases it is a good
idea. There are some who may argue this, but data points
are really the only thing worth discussing.

I'll have some new hardware in May and I plan on
re-running the tests mentioned in the article.

--
Doug

> is it possible to have a single multicored machine as a cluster?
>
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> Jonathan Aquilina
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--
Doug

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