[ET Trac] [Einstein Toolkit] #530: Change default for --num-threads

[Einstein Toolkit]

#530: Change default for --num-threads
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  Reporter:  eschnett     |       Owner:  hinder  
      Type:  enhancement  |      Status:  assigned
  Priority:  major        |   Milestone:          
 Component:  SimFactory   |     Version:          
Resolution:               |    Keywords:          
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Comment (by knarf):

 Right, I forgot about that (again). But that leaves us an an ugly
 situation:

 - Simfactory would have to know about the number of threads because the
 number of mpi processes depends on it
 - Only Cactus would know which thorns are active in a given simulation,
 and could deduce from that if thorns 'request' only one thread.

 I see only two possible ways out:
 a) Simfactory parses the parameter file for the active thorns, and gets
 from somewhere (the build directory most likely) the information whether
 thorns request one-thread-only.
 b) We replace the run-time dependency of the single-thread-request with a
 compile-time dependency and say that a given configuration requests
 single-thread execution depending on the thorns which are compiled in.
 This is against the modular Cactus approach, but it would mean that
 simfactory wouldn't have to parse the parameter file and could rely on a
 single entry in the configuration.

 I would prefer solution a) if feasable. Doesn't simfactory already parse
 parameter files for active thorns, and disables them if the machine
 specified this?

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Ticket URL: <https://trac.einsteintoolkit.org/ticket/530#comment:8>
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