Abstract
The performance promised for parallel systems often proves to be somewhat elusive. This paper discusses one important technique for improving the performance of parallel software: program visualization - helping programmers visualize the real behavior of an application or system by presenting its state and progress in a continuous graphic fashion. An environment for visualization of program execution is described. Within this visualization environment, programmers dynamically establish views of the behavior of a program in execution and watch for trends, anomalies, and correlations as information is displayed. By continually refining the view of the program and replaying the execution of the program, programmers can gain an understanding of program (mis)behavior. This is essential for the debugging, performance analysis, and tuning of parallel software. Design goals for the visualization environment include expandibility, portability, and the ability to accommodate diverse architectures, including highly parallel shared-memory systems and large-scale message-passing systems. Results from visualization of systems and applications running on the RP3, an experimental shared-memory multiprocessor, are presented in the form of color reproductions of typical, useful displays.