Analyzing schedulability of astral specifications using extended timed automata

Abstract

This paper reports our experiences with using an extension of timed automata [1] for schedulability analysis of prototype implementations. The approach builds upon requirements specifications constructed using the formal real-time specification language Astral [7]. Astral specifications are translated into extended timed automata. The resulting automata are augmented with implementation details like assignment of processes to processors, priorities, worst-case execution times of operations, and scheduling policies. Schedulability analysis is then performed by (automated) formal verification of the extended automaton.

Schedulability analysis of AADL models

“…Extensions of timed automata are used in [5,2,8], however, continuous time model does not seem to fare well with the discrete nature of scheduling decisions, resulting in much more cumbersome analysis algorithms. More significantly, ACSR is the only formalism that treats resource contention directly in the semantics, avoiding complicated encodings necessary in other formalisms, which considerably increase the size of the model.…”