Performance and dependability evaluation of scalable massively parallel computer systems with conjoint simulation

Computer systems are becoming more and more a part of our daily life; business and industry rely on their service, and the health of human beings depends on their correct functioning. Computer systems used for critical tasks have to be carefully designed and tested during the early design stage, the prototype phase, and their operational life. Methods and tools are required to support and facilitate this vital task. In this article, we tackle the issue of system-level performance and dependability analysis of fault-tolerant scalable computer systems. A modeling methodology called “Conjoint Simulation” is presented, which is based on the parti tioning of the system model and the combination of several modeling techniques. Object-oriented model construction and process-based simulation are applied for architecture and workload modeling, and timed Petri nets are the core modeling technique representing the failure scenarios and repair policies. Splitting the overall model and exploiting appropriate modeling techniques ease the development, maintenance, and extensibility of large-scale and complex simulation models. Furthermore, techniques are provided for hierarchical model construction, object-oriented workload modeling, and simulated error injection in order to perform combined performance and dependability analysis.