Schedulability Analysis for Real-Time Task Set on Resource with Performance Degradation and Periodic Rejuvenation

Most schedulability analyses in the literature assume that the performance of computing resource does not change over time. However, due to ever increased complexity of computer systems, software aging issues become more difficult, if not impossible, to eradicate. Hence, the assumption that computing resource has a constant performance in its entire lifetime does not hold in real world long-standing systems. In this paper, we study real-time task schedulability under a resource model that the resource´s performance degrades with a known degradation function and the resource is periodically rejuvenated. The resource model is referred to as P2-resource model for performance degradation and periodic rejuvenation. We address three real-task schedulability related questions under the P2-resource model, i.e., (1) resource supply bounds of the P2-resource, (2) task set utilization bounds under Earliest Deadline First (EDF) and Rate Monotonic (RM) scheduling policies, respectively, and (3) experimentally study the tightness of the bounds developed, and the impact of resource degradation rate, rejuvenation period, and rejuvenation cost on the bounds.