A compiler-based communication analysis approach for multiprocessor systems

In this paper we describe a compiler framework which can identify communication patterns for MPI-based parallel applications. This has the potential of providing significant performance benefits when connections can be established in the network prior to the actual communication operation. Our compiler uses a flexible and powerful communication pattern representation scheme that can capture the property of communication patterns and allows manipulations of these patterns. In this way, communication phases can be detected and logically separated within the application. Additionally, we extend the classification of static and dynamic communication patterns and operations to include persistent communications. Persistent communications appear dynamically, however, they remain unchanged for large segments of the application execution. Our compiler is capable of detecting both static and persistent communication patterns within an application. We show that for the NAS parallel benchmarks, 100% of the point-to-point communications can be classified as either static or persistent and, with the exception of IS, 100% of the collective were either static or persistent. By comparison to application trace data, the predicted LBMHD, CG and MG communication patterns have been verified