[ET Trac] [Einstein Toolkit] #1850: Severe performance problem on Stampede

[Einstein Toolkit]

#1850: Severe performance problem on Stampede
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 Reporter:  hinder      |       Owner:                     
     Type:  defect      |      Status:  new                
 Priority:  major       |   Milestone:                     
Component:  SimFactory  |     Version:  development version
 Keywords:              |  
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 With the ET_2015_11 release, there is a severe performance problem on
 Stampede.  This is when hwloc and SystemTopology are not activated.
 Activating these thorns causes simulations to run 8 times faster.    This
 suggests that the affinity settings in simfactory for stampede are wrong.
 stampede-mvapich2.run has
 {{{
 export KMP_AFFINITY=norespect,compact # verbose
 }}}
 Is this correct?  Looking at the output of "top", we see the expected 16
 threads, but each is running at only 50%.  There is no migration between
 cores, as far as we can tell.  This 50% should be 100%, and this doesn't
 explain the factor of 8 slowdown, but it shows that there is something
 wrong.

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Ticket URL: <https://trac.einsteintoolkit.org/ticket/1850>
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