New schedulability analysis for real-time systems based on MDE and Petri Nets model at early design stages

摘要

Transforming a software functional model that describes the underlying application to a concurrency model is considered as a critical issue in the model-based approaches for Real-Time Embedded Systems (RTES) development process. The formal methods have proven to be useful for making the development process reliable at a high abstraction level. Based on this approach, this current research proposes a generic approach to task construction that allows early detection of unfeasible design. Having a component-oriented specification as entry, the first stage of the methodology consists in the workload model specification. The workload model represents the system end-to-end computations triggered by an external stimulus and subject to hard real-time constraints. This model is then mapped into a Petri Nets formalism to perform P-invariant method and generate all transactions in an optimized way. The refinement of the transaction set in a Schedulability Analysis Model defining an optimized threading strategy model. The latter presents the set of units of execution taken into account by the scheduler of the system and their scheduling parameters. We illustrate the advantages and effectiveness of the proposed method by constructing a concurrency model for a combined Cruise Control System and Anti-lock Braking System.