Visualizing the program execution control flow of openmp applications

Abstract

One important aspect of understanding the behavior of an application with respect to its performance, overhead, and scalability characteristics is knowledge of its control flow. In comparison to sequential applications the situation is more complicated in multithreaded parallel programs because each thread defines its own independent control flow. On the other hand, for the most common usage models of OpenMP the threads operate in a largely uniform way, synchronizing frequently at sequence points and diverging only to operate on different data items in worksharing constructs. This paper presents an approach to capture and visualize the control flow of OpenMP applications in a compact way that does not require a full trace of program execution events but is instead based on a straightforward extension to the data collected by an existing profiling tool. © 2008 Springer-Verlag Berlin Heidelberg.