VPPB: A visualization and performance prediction tool for multithreaded Solaris programs

Efficient performance tuning of parallel programs is often hard. In this paper we describe an approach that uses a uni-processor execution of a multithreaded pro-gram as reference to simulate a multiprocessor execution. The speed-up is predicted, and the program behaviour is visualized as a graph, which can be used in the perfor-mance tuning process. The simulator considers scheduling as well as hard-ware parameters, e.g., the thread priority, no. of LWPs, and no. of CPUs. The visualization part shows the simu-lated execution in two graphs: one showing the threads’ behaviour over time and the other the amount of parallel-ism over time. In the first graph is it possible to relate an event in the graph to the code line causing the event. Vali-dation using a Sun multiprocessor with eight processors and five scientific parallel applications shows that the speed-up predictions are within +/-6 % of a real execution. 1