Fuzzy EDF Algorithm for Soft Real Time Systems
Vijayakumar Ponnusamy, P. Aparna · 2010
EDF is a classic dynamic embedded real- time multi-task scheduling algorithm. In an embedded soft real-time system, the deadline missing ratio is an important metric to evaluate system performance. When an embedded soft real- time system is overloaded, EDF algorithm is not effective. Considering the unsteadiness and unpredictability of a practical task running environment due to the unsteadiness of network communication and the time estimation deviation, it is necessary to introduce Fuzzy concept and theory to the scheduling field of embedded soft real-time application systems. In fuzzy scheduling model, all task's criticality and deadline distance are described with Fuzzy set. In our scheduling algorithm, a task's scheduling priority is gotten by looking up the inference rule table with its Fuzzy deadline distance and Fuzzy criticality patterns. By comparing to traditional EDF algorithm to FUZZY EDF Algorithm FUZZY EDF Algorithm will have the less miss dead line ratio.