A FORMALIZATION OF PRIORITY INVERSION

A priority inversion occurs when a low-priority task causes the execut ion of a higher-priority task to be delayed. The possibility of priori ty inversions complicates the analysis of systems that use priority-ba sed schedulers because priority inversions invalidate the assumption t hat a task can be delayed by only higher-priority tasks. This paper fo rmalizes priority inversion and gives sufficient conditions as well as some new protocols for preventing priority inversions.