The goal of dynamic priority scheduling is to adapt to dynamically changing progress and to form an optimal configuration in a self-sustained manner.
It can be very hard to produce well-defined policies to achieve the goal depending on the difficulty of a given problem.
[1] In periodic real-time task model, a task's processor utilization is defined as execution time over period.
Every set of periodic tasks with total processor utilization less or equal to the schedulable utilization of an algorithm can be feasibly scheduled by that algorithm.
Unlike fixed priority, dynamic priority scheduling could dynamically prioritize task deadlines achieving optimal schedulable utilization in the preemptible case.