[fpc-devel] Parallel Computing

Florian Klaempfl florian at freepascal.org
Mon Nov 3 15:17:57 CET 2008

Michael Schnell schrieb:
>> I don't see how Mandelbrot requires OpenMP. One can easily launch n
>> threads depending on the number of the available cores.
> (We are discussing this in the German Lazarus Forum right now...)
> I feel that OpenMP is never _required_ to optimize a problem, but just
> adds a high level of programming convenience to a language.

It solves none of the real problems of MT programming.

> In fact the "Mandelbrot" test is not even done with threads (or OpenMP)
> in GNU-C. Someone else in the German Lazarus Forum said he found
> threading in some tests done in C and on none done in Pascal, leading to
> an unfair result on multicore machines.
> But doing _explicit_ threads in FPC would not be allowed according to
> the rules in ALIOTH: they only allow simple programming and not complex
> tricks so that the source code for a test case is similar with among all
> languages. I suppose adding a "#pragma omp_parallel for" line in the C
> source or a "parallel" keyword in a for statement in FPC or Oxygen would
> be nice, while explicitly creating multiple threads would be denied.

I don't care about this then :) IIRC the Mandelbrot benchmark is full of
vector macro hacking, if they deny then proper thread starting they
should better spent their time in usefull things.

Several years ago I had a look at OpenMP and I consider it as one of the
most useless extensions for real world applications. It adds no benefit
to the real problems of MT programming.

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