Real-Time Operating Systems

Jackson’s algorithm
[1955]
¿ 1 | sync | L max
¿ No other constraints are considered:
¿ tasks are independent
¿ no precedence relations
¿ Task set J = {J i (C i , D i ) | i = 1…n}
¿ Computation time C i
¿ Deadline D i
¿ Principle: Earliest Due Date (EDD)
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Jackson’s algorithm (2)
¿ It can be proved that:
¿ Given a set of n independent tasks, any algorithm that
executes the tasks in order of nondecreasing deadlines
is optimal with respect to minimize the maximum
lateness.
¿ Complexity: sorting n values (O(nlogn))
¿ EDD can not guarantee feasible schedule.
It only guarantees that if a feasible schedule
exists it will find it
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