An Evaluation of the Memory Reference Behavior of Engineering/Scientific Applications in Parallel Systems

This paper presents the results of a study conducted to evaluate the inherent memory reference behavior of several engineering/scientific applications, executing on shared memory, MIN-based, parallel systems. In this study, system sizes of two to 64 processors were evaluated. A trace-driven simulation model was used to obtain dynamic reference characteristics of the code. Included in this code were explicit declarations of shared variables. Our results indicate that a significant amount of explicitly declared shared data is accessed as either readonly by several processors, or read-write by a single processor. Furthermore, lines containing synchronization variables tend to see small ownership times at a processor and are accessed by several processors in the system. We also note that, as expected, relatively more references are to data with smaller ownership times, as the number of processors increase. Finally, the application data set size can have an impact on ownership time, as the number of processors increase.