Cube GUI User Guide  (CubeGUI 4.6-rc1, revision cfc8481d)
Introduction in Cube GUI and its usage

MPI Communication Efficiency

MPI Communication Efficiency (CommE) can be evaluated directly by following formula:

CommE = max( computation time ) / max( runtime )

CommE identifies when code is inefficient because it spends a large amount of time communicating rather than performing useful computations. CommE is composed of two additional metrics that reflect two causes of excessive time within communication:

These are measured using Serialization Efficiency and Transfer Efficiency. Combination of these two sub-metrics gives us Communication Efficiency:

CommE = Serialization Efficiency * Transfer Efficiency

To obtain these two sub-metrics we need to perform Scalasca trace analysis which identifies serializations and inefficient communication patterns.


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