[ET Trac] [Einstein Toolkit] #2008: NaNs when running static tov on >40 cores

[Einstein Toolkit]

#2008: NaNs when running static tov on >40 cores
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  Reporter:  allgwy001@…            |       Owner:  knarf     
      Type:  defect                 |      Status:  assigned  
  Priority:  unset                  |   Milestone:            
 Component:  Other                  |     Version:  ET_2016_05
Resolution:                         |    Keywords:            
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Comment (by allgwy001@…):

 Here are some comments I received from the person who compiled the
 Einstein Toolkit on the cluster I'm using. He ran tests with the static
 tov star parameter file I attached, and sent me the following:

 "The times follow a standard MPI reduction pattern. Out beyond 24 cores
 the code/data does not scale well and latency from message passing starts
 to increase rather than reduce run times. Some increases in ppn values
 increase the run times; this may be due to how data objects are handled in
 the code. There is also some fluctuation in the data runs which can only
 be caused by the software as I ran all tests on node 607 while no one else
 was using it."

 He suggested that if I want to do runs on more than 20 cores (which I do),
 then I should ask for advice from people more familiar with the Einstein
 Toolkit.

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Ticket URL: <https://trac.einsteintoolkit.org/ticket/2008#comment:2>
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