A Novel Least Slack First Scheduling Algorithm Optimized by Threshold

In order to prevent that the least slack first scheduling algorithm may frequently cause switching among tasks, a novel least slack first scheduling algorithm based on dynamic fuzzy preemption is presented. The notion of threshold coefficient was defined in this paper, linguistic fuzzy sets were used to describe the uncertain characters and the fuzzy threshold coefficient was gotten by fuzzy logic. The slack time of the running task is reduced to its fuzzy threshold to avoid thrashing. Comparing to the traditional least slack first scheduling algorithm, the simulation results show that, the switching number of the novel algorithm is smaller and the missed deadline percentage is decreased.