Distance Constrained Tasks

Scheduling problems that involve distance constraint tasks with repetitive requests is becoming increasingly popular in real time systems. Timing constraints defined by periods of fixed lengths for each task enforce some frequency of task execution. Alternatively deadlines could be specified relatively to the finish time of the previous execution of the same task. Hence the scheduling algorithms deal with tasks that virtually consist of infinite chains of jobs with specified temporal distance constraints between each pair of adjacent jobs. In this paper, unlike approaches that consider a preemptive distance constrained tasks scheduling subject to minimize time distance between task execution, we consider a problem of non preemptive tasks system with objective to reduce processor utilization while keeping the response times within their limits. As a consequence, free processor capacity remains to process sporadic tasks.