Fixed-Priority Schedulability of Sporadic Tasks on Uniprocessors is NP-Hard

Abstract

We study the computational complexity of the FP-schedulability problem for sporadic or synchronous periodic tasks on a preemptive uniprocessor. We show that this problem is (weakly) NP-hard, even when restricted to either (i) task sets with implicit deadlines and rate-monotonic priority ordering, or (ii) task sets with constrained deadlines, deadline-monotonic priority ordering and utilization bounded by any constant c, such that 0 c 1.