[Openmp-commits] [PATCH] Allow machine hierarchy expansion
terry.l.wilmarth at intel.com
Thu May 28 09:08:35 PDT 2015
It does represent the machine hierarchy, when there is no oversubscription, but it is actually used as a way to map existing threads to the machine hierarchy for the purpose of performing a barrier. Adding a level when oversubscribed simply adds more tree structure for all the additional threads to communicate along. One additional level duplicates the existing hierarchy as a second child of a new root, doubling the number of threads that the barrier can handle.
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