Parallelism Viewpoint: A Viewpoint to Model Parallelism in Parallelism-Intensive Software Systems

The use of parallelism enhances the performance of a software system. Its excessive use, however, can degrade the performance. In this paper we propose a parallelism viewpoint to optimize the use of parallelism by eliminating unnecessarily used threads in legacy systems. The viewpoint describes the parallelism behaviour of the system, which can be used to analyze for overheads associated with threads. We illustrate the proposed viewpoint with the help of an industrial case, a parallelism-intensive electron microscope software system. We use the viewpoint to analyze threads suitable to be replaced with a small sized thread pool in this system. Results show that the viewpoint provides a profound insight into the thread-model of the system that is required to reduce the parallelism. In the thread pool analysis, we found that more than 50% threads are underused. They were replaceable with a pool of approximately 11% of these threads.