Periodic real-time scheduling: from deadline-based model to latency-based model

This paper presents a connection between two real-time models: a deadline-based model and a latency-based model. The importance of the latency-based model is proved through a result showing that two deadlines, instead of a latency constraint, over-constrain the realtime applications. Moreover, we give a deadline-marking algorithm based on the relation between deadlines and latency constraints. This algorithm provides non-preemptive feasible schedules for systems with precedence constraints and deadlines, or more complex systems with deadlines and latencies. This is the first step toward non-preemptive schedulability for distributed architectures (without over-constraining the system) like, for example, the automotive applications using protocols such as Controller Area Network (CAN).