Processor Bounding for an Efficient Non-preemptive Task Scheduling Algorithm

The scheduling problem, which is the core of all approaches related to real-time systems, has received proper attention from the research community. However, while preemptive scheduling has benefited from most of the results to date, the more difficult case of non-preemptive scheduling is still lacking similar achievements. This paper is approaching non-preemptive scheduling from two different angles. First, the number of processors that would allow a feasible schedule for a given task set is analyzed, yielding both lower and upper limits which can be determined in polynomial time. Second, a hybrid scheduling algorithm, combining two widely known techniques, namely EDF and LLF, is proposed and tested. A common feature of both objectives is the transition from a single-instance task to a periodic task. The relationships between these two cases are investigated, resulting in a better understanding of periodic behavior.