OPTIMIZED PERFORMANCE OF CPU SCHEDULING

Abstract

CPU scheduling is the problem of deciding which computer process in the ready queue is to be allocated to the CPU for processing. It is a fundamental problem in operating systems in terms of minimizing the wait for the user when he or she simply wants to execute a particular set of tasks. There are many CPU scheduling algorithms, which solve this problem. Some of them are as FCFS, SJF, Round Robin, and Priority Algorithm etc.Different algorithms have different strengths, and no single one is ideal for every situation. Therefore, we need techniques for analyzing the characteristics of each algorithm in order to make an informed choice. Criteria for CPU scheduling include such as, (i) Maximum CPU utilization under the constraints that the maximum response time is 1 second. (ii) Maximum throughput such that turnaround time is linearly proportional to execution time. (iii) Turnaround time is time taken by process to execute. (iv)Waiting Time is the sum of the periods spent waiting in the ready queue. (v) Response Time is the interval between submissions of a request until the first response is produced. Once the selection criteria have been defined, there is a need to evaluate the various algorithms under consideration. There are number of different evaluation method. One of the evaluation method is called analytic evaluation. Analytic evaluation uses the given algorithm and the system workload to produce a formula or number that evaluates the performance of the algorithm for that workload. One type of analytic evaluation is deterministic modeling. This method takes a particular predetermined workload and defines the performance of each algorithm for that workload. In this thesis research work, different CPU scheduling methodologies (FIFO, SJF, Round Robin, and Priority) have been evaluated. A simulator have been developed which analyzes these algorithm based on Average Waiting Time (AWT). By using result of deterministic evaluator, an optimized solution for Round Robin is proposed for time sharing system. This Optimized solution has better performance than Existing Round Robin with respect to Average Waiting Time (AWT).