[ET Trac] [Einstein Toolkit] #1722: hwloc could warn the user if a process spans more than one NUMA node

[Einstein Toolkit]

#1722: hwloc could warn the user if a process spans more than one NUMA node
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  Reporter:  hinder                 |       Owner:                     
      Type:  enhancement            |      Status:  confirmed          
  Priority:  minor                  |   Milestone:                     
 Component:  EinsteinToolkit thorn  |     Version:  development version
Resolution:                         |    Keywords:                     
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Comment (by eschnett):

 In the same spirit, hwloc should detect if the current MPI process started
 up with a sub-ideal memory affinity. Other libraries, in particular MPI,
 may be initialized before hwloc runs, and these would see and use the sub-
 ideal memory affinity. This is actually causing slow-downs on some
 systems.

 Another remedy for this could be to run hwloc very early, before MPI is
 initialized. This would require passing in the current MPI rank, which may
 not be possible before initializing MPI.

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Ticket URL: <https://trac.einsteintoolkit.org/ticket/1722#comment:2>
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