[Beowulf] multi-threading vs. MPI

[Joe Landman]

Greg Lindahl wrote:
> On Mon, Dec 10, 2007 at 07:40:15PM -0500, Joe Landman wrote:
> 
>> b) the only code that matters is your code (really, this should be 
>> everyone's mantra with benchmarking in general).
> 
> Well, the problem here is that the question most people are asking is,
> "how should I parallelize my code?" This question gets asked before
> you know the performance on your code.
> 
> So the mantra doesn't help.

On the contrary, it is precisely because people are asking "how should I 
parallelize" that they need to ask the basic question of "where does my 
code spend time for my problems."

Most people I know working on parallelization or optimization have at 
least asked that question.

Starting parallelization without this knowledge in advance is an 
exercise pretty much guaranteed to fail.  Unless you happen to be an 
extremely lucky guesser.



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Joseph Landman, Ph.D
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