A Compositional Framework for Real-Time Guarantees

We address the problem of combining the collective hard real-time resource requirements into a single hard real-time resource requirement supporting composability. We first propose a resource model to characterize a periodic resource allocation and present exact schedulability conditions for our proposed resource model under the EDF (earliest deadline first) and RM (rate monotonic) algorithms. Using the exact schedulability conditions, we then provide methods to abstract the real-time resource requirements that a set of periodic tasks demands under the EDF and RM algorithms as a single periodic task. With these abstraction methods, we introduce a composition method that derives a new temporal requirement from multiple temporal requirements in a compositional manner such that the new temporal requirement is satisfied, if and only if, the multiple temporal requirements are satisfied together.