A system is schedulable (and feasible) if and if it is schedulable by some algorithms. A scheduling algorithms can feasibly schedule any set of periodic tasks on a processor if the total utilization of tasks is equal to or less than schedulable utilization of algorithms. The higher the schedulable utilization of an algorithms, better the algorithms. Since, no algorithms can feasibly schedule a set of tasks with a total utilization greater than 1, an algorithms can feasibly whose schedulable utilization is equal to 1 is an optimal algorithms.

Schedulable Utilization of the EDF Algorithm: