The PEDAS design representation for performance engineering of distributed systems

The authors describe PEDAS (performance expert for design analysis of software), a software tool that supports performance engineering of distributed systems. The user describes distributed systems through graphical specification of software and data flows, hardware architecture, and workloads. The PEDAS design representation language allows explicit specification of software partitioning and allocation along with their associated performance overheads, e.g. the Ada rendezvous. Using an analytic model, PEDAS computes the performance characteristics of distributed systems. Performance results are automatically compared to user-supplied requirements, and causes of performance shortfalls are analyzed. The user can thus experiment with alternative distribution strategies as well as with the tradeoff between greater concurrency and the overhead caused by communication primitives. A preliminary evaluation indicates that the representation provides a natural conceptual model of distributed systems and software, which facilitates its ease of use