An Analysis of Deadline-Monotonic Schedulability on a Multiprocessor

A new schedulability test is presented for preemptive deadline-monotonic scheduling of periodic or sporadic real-time tasks on a single-queue m-server system. This generalizes and extends a result of Andersson, Baruah, and Jonsson, for the case where deadline equals period, which showed all deadlines will be met if the total utilization is at most m=(3m 1) and the utilization of each task is at most m=(3m 2). The new condition does not require that the task deadline be equal to the period, and can be used to verify schedulability for task sets with higher total utilizations or lower individual task utilizations. In addition to the lower bound on the minimum achievable utilization, an upper bound of +m ln( 2 1+ ) is derived.

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