Indian Journal of Science and Technology

Abstract

Background: If the processer knows in advance how much time each process takes then the best approach is shortest job first scheduling (SJFS). But knowing the burst time before hand is usual unrealistic. Round Robin scheduling algorithm (RR) is the most commonly used scheduling algorithm in an environment with time sharing among more than one process. RR algorithm is free from starvation, since all processes always get equal time quantum. But the selection of time quantum can influence the performance of the algorithm. If too short, an inordinate fraction of the time is spent in context switches. If too large, it behaves like first come first served (FCFS). We try to improve this aspect of the algorithm. Methods:We propose a variant of RR algorithm -Dynamic Time Slice Round Robin Scheduling Algorithm with Unknown Burst Time which could be used if the burst times of the processes are unknown at the beginning. This involves tuning the time quantum at run time. Findings:With the proposed method we find that 15% reduction in average waiting time,15% in average turnaround timeand number of context switches can be achieved10%.

Keywords: CPU, Scheduling criteria, Scheduling algorithm, Round Robin scheduling, Context switch, Dynamic Time Slice Round Robin Scheduling Algorithm with Unknown Burst Time.