[GitHub] stsukrov edited a comment on issue #14087: Poor performance of the libmxnet if OMP_PLACES environment variable is present

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stsukrov edited a comment on issue #14087: Poor performance of the libmxnet if OMP_PLACES environment variable is present
URL: https://github.com/apache/incubator-mxnet/issues/14087#issuecomment-461476853
 
 
   @pengzhao-intel 
   Thanks for a response, Patric!
   
   Tried.
   Same story if OMP_PLACES is present **AND** 2 OMP runtimes are loaded.
   
   It's issue about having an regression, IF something is present, not about existing good configuration.
   
   My assumption: it's caused by multiple OMPs, since it's gone as soon as I symlink gomp to iomp5.
   
   To my knowledge, (source: https://www.youtube.com/watch?v=Y7eVVfyo0U4, Michael Klemm) 
   KMP_AFFINITY is deprecated for usecases other than **verbose**.
   
   KMP_AFFINITY=granularity=fine,compact,1,0 
   
   is roughly
   
   OMP_PLACES=cores
   OMP_PROC_BIND=close
   
   Right?
   
   Recall, I'm talking about 10x performance regression.
   Missing KMP_AFFINITY gives like 1.5 worse performance, which is understandable.  

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