Compositional design of isochronous systems

The synchronous modeling paradigm provides strong correctness guarantees for embedded system design while requiring minimal environmental assumptions. In most related frameworks, global execution correctness is achieved by ensuring the insensitivity of (logical) time in the program from (real) time in the environment. This property, called endochrony or patience, can be statically checked, making it fast to ensure design correctness. Unfortunately, it is not preserved by composition, which makes it difficult to exploit with component-based design concepts in mind. Compositionality can be achieved by weakening this objective, but at the cost of an exhaustive state-space exploration. This raises a trade-off between performance and precision. Our aim is to balance it by proposing a formal design methodology that adheres to a weakened global design objective: the non-blocking composition of weakly endochronous processes, while preserving local design objectives for synchronous modules. This yields an effective and cost-efficient approach to compositional synchronous modeling.