Performance Comparison of RTS Scheduling Algorithms
Amit Sandhu · 2011
In this paper Real Time Scheduling Algorithms are proposed for both preemption and non-preemptions, to fulfill the deadline constraint for which simulation techniques are used, where these proposed algorithms are implemented and results are shown in Gantt charts and graphs. In this we find out the power consumption, load of the CPU and remaining time of the task using different algorithms. We are taking task with shortest completion time. Keyword GTFD_U, GTFD_M, RRQ_P, RRQ_NP, WCET I. Introduction The Oxford Dictionary of Computing [1] defines a real-time system as: Any system in which the time at which output is produced is significant. This is usually because the input corresponds to some movement in the physical world, and the output has to relate to that same movement. The lag from input time to output time must be sufficiently small for acceptable timeliness. Scheduling Algorithms in Real Time System can be classified among many dimensions. Some Scheduling Algorithms deal only periodic tasks, while others are intended to deal both periodic and aperiodic. Similarly, some algorithms allow preemption of executing tasks, while other can be non preemptive in nature. Precedence relationships, resource constraints, importance of deadline (soft, firm and hard tasks) are some other characteristics of Real Time Systems, While affect the nature of scheduling algorithms. The scheduling algorithms also depend on the types of systems for which they are intended. Some are for Uniprocessor, while other are for multiprocessor systems. Thus Scheduling algorithm can be classified into different categories [2], depending on whether a system performs feasibility analysis or not, if it does, whether it is done offline (at design time) or online (dynamically), and whether the result of analysis itself produces a schedule or plan according to which tasks are dispatched at run time, and postponement of scheduling decision up to the occurrence of certain conditions. II. System Model In this section I am presenting assumptions, terminology in real time scheduling aspect. A. Assumptions • Set of tasks Ti every task has attribute arrival time, Deadline, Worst case execution time. • Priorities of the task, priorities are set according to the