University of Missouri-St. Louis
In this paper, the authors present a new strategy to arbitrate the access to globally shared resources in hierarchical EDF scheduled real-time systems, without needing any information on the duration of each critical section. Previous works addressing this problem assumed each task worst-case critical section length is known in advance. However, this assumption is valid only in restricted system domains, and is definitely inadequate for general purpose real-time operating systems. To sidestep this problem, they will instead measure at run-time the amount of time for which a task keeps a resource locked; assuring that there is enough bandwidth to tolerate the interferences associated to such measured blocking times.