Priority inversion with fungible resources

Abstract

Priority inversion occurs when the execution of a task is unnecessarily delayed by the dispatch of a lower priority task. This anomaly can result in failure if it causes the delay of hard real-time tasks. Priority inheritance protocols have been developed to limit priority inversions during competition over shared resources. Such methods are designed for individually identifiable resource units. Other approaches are indicated when shared resources contain interchangeable resource units. Current practices with resource deadlock, a scheduling anomaly that has many characteristics in common with priority inversion, provide insight into the control of priority inversion with these fungible resources.