yade-dev team mailing list archive

[Bruno Chareyre <bruno.chareyre@xxxxxxxxxxx>]

This is really interesting.
It sounds like we could nest paralellizations, with parallelized engines 
runing in parallel.

>> however, running the loops in parallel is not necessarily a speed
>> gain.

How comes?!

Bruno


Bruno Chareyre a écrit :
> Do you know that, appart from the IMAG student working on Python, we 
> have also one working on paralellization of Yade during summertime?
> If I understand correctly, you run different engines in parallel, but 
> engines themselves are not parallelized. Correct?
>
> Bruno
>
>
>
> Václav Šmilauer a écrit :
>   
>> I just commited ParallelEngine class that uses openmp to run engines in
>> parallel. I have 16% speedup on simple-scene.py vs.
>> simple-scene-parallel.py (dual-core machine, but the second core is 100%
>> used). I think the impact will be bigger on larger simulations. If you
>> get mysterious crashes while useing ParallelEngine, run with
>> OMP_NUM_THREADS=1 to make sure. Do not use it unless you are sure the
>> engines you run in parallel do not touch the same data.
>>
>> I will soon start to parallelize inner loops of engines where it makes
>> sense - like gravity engine, InteractingGeometryMetaEngine,
>> InteractionPhysicsMetaEngine. None of the changes will be intrusive,
>> though, and compiling without openmp enabled (or /setting
>> OMP_NUM_THREADS=1 in the shell) /will keep the old behavior.
>>
>> For engines that loop over physical actions, that will be more
>> complicated, since openmp needs const-time random access to
>> integer-indexed elements; we will see.
>>
>> Please let me know if you get some speedups. Ah, not to forget: use
>> gcc>=4.2 to compile.
>>
>> Vaclav
>> _______________________________________________
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>>
>>   
>>     
>
>
>   


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