These challenges require not only appropriate modeling support, they require also early feed-back from customers. Bangalore We consider a two level decomposition of onboard realtime systems into repetitive major cycles, each one split in k minor cycles. The minor and major tasks are available at the beginning of their respective cycles and must be complete within them.
All tasks have non deterministic execution times and are performed an a set of uniform processors.
Minor tasks have priority on major ones which may only use the remaining time left in the k minor cycles. A first colored stochastic net describes the dynamic management of minor tasks. Then it is embedded in second model for the scheduling and preemption of major tasks. The completion probabilities of the two sets of tasks are studied for several dynamic scheduling heuristics. The architecture of the toolset is based on a layer structure to generate and evaluate performance models, which have been generated automaticly from the PRM-specification.