Dynamic scheduling of real-time tasks, by assignment

Sequencing and assignment are two important issues we need to address a when scheduling real-time tasks on a multiprocessor architecture. Different problem representations can schedule such tasks, each emphasizing either a sequencing or assignment task. A sequence-oriented representation satisfies problem constraints by emphasizing the search for an appropriate tasks order, while an assignment-oriented representation emphasizes the search for an appropriate assignment of tasks. The authors introduce the RT-SAD algorithm, which uses an assignment-oriented representation to dynamically schedule tasks on the processors of a NUMA architecture. The proposed technique automatically controls and allocates the scheduling time to minimize the scheduling overhead and deadline violation of real-time tasks. The authors compare RT-SADS performance with another dynamic algorithm that uses a sequence-oriented representation. The results show interesting performance trade-offs among the candidate algorithms.