Visualizing the execution of High Performance Fortran (HPF) programs

Although the data placement programming model frees programmers from writing low level communication code, it also makes it harder for them to anticipate the performance of the code they write. In particular, the communication that is required by a given data distribution, and its impact on performance, may not be obvious from the program source. Many existing performance visualization systems could be used in attempts to investigate the performance of data placement programs; however, no published system would provide views that relate communication activity to the abstraction that is the primary focus of data placement programming: data distribution. The paper introduces new high level views of HPF program behavior that show communication activity in the context of the array distribution from which the compiler derived the communication. With these views, programmers can see not only when and where communication takes place, but also what subarrays are moving between which processors by virtue of the communication. These views provide programmers with feedback in terms of the programming model-the programmers´ frame of reference. The programming model as the level programmers most readily comprehend, and it is the level at which they must improve program performance by altering data distribution. Thus, these views provide a basis for effective tuning of data placement programs