Scheduling of Dependent Real-Time Tasks Using Fuzzy Logic Technique

Abstract

Many scheduling algorithms have been studied to guarantee the time constraints of real-time processes. Scheduling decision of these algorithms is usually based on parameters which are assumed to be crisp. However, in many circumstances the values of these parameters are vague. Moreover, reducing energy consumption is a critical issue in the design of battery-powered real time systems to prolong battery life. With dynamic voltage scaling (DVS) processors, energy consumption can be reduced efficiently by making appropriate decisions on the processor speed/voltage during the scheduling of real time tasks. Therefore, a fuzzy logic approach is proposed to reduce energy consumption by determining the appropriate supply-voltage/speed of the processor provided that timing constraints are guaranteed.   Intensive simulated experiments and qualitative comparisons with the most related literature have been conducted in the context of dependent real-time tasks. Experimental results have shown that the proposed fuzzy scheduler saves more energy and creates feasible schedules for real time tasks. It also considers tasks priorities which cause higher system utilization and lower deadline miss time.

Keywords: dynamic voltage scaling (DVS) processors, fuzzy logic approach, real-time tasks.