Visualisation for performance tuning of DVSM applications

Small organisations can now have access to high raw processing power using networks of workstations (NOW) as parallel computing platforms. Distributed Virtual Shared Memory (DVSM) packages have been developed to facilitate the programming of such systems. However, because of the high interprocess latencies in a NOW, the performance of a DVSM application is more susceptible to the partitioning of the problem than what might be expected. The paper presents an approach for a tool to visualise the execution of a program in a way that highlights performance bottlenecks. The tool associates identified bottlenecks with the corresponding source code lines in order to determine what piece of code is the cause of poor performance. The visualisation technique is demonstrated in two case studies. They clearly show that the visualisation is indeed useful and provides an effective way to acquire an understanding of what characterises an application sharing behaviour