FCFS Scheduling(Cont Suppose that the processes arrive in the order(假定进程到达顺序 如下)P2,P3,P1 The gantt chart for the schedule is(该调度的Gant图为) 0 3 6 30 ° Waiting time(等待时间)forP1=6;P2=0.P3= ° Average waiting time(平均等待时间):(6+0+3)/3=3 Much better than previous case(比前例好得多) Convoy effect short process behind long process (此种结果产生是由于长进程先于短进程到达) Applied Operating System Concepts 6.10 Silberschatz, Galvin, and Gagne @19996.10 Silberschatz, Galvin, and Gagne ©1999 Applied Operating System Concepts FCFS Scheduling (Cont.) Suppose that the processes arrive in the order （假定进程到达顺序 如下） P2 , P3 , P1 . • The Gantt chart for the schedule is （该调度的Gantt图为） : • Waiting time （等待时间） for P1 = 6; P2 = 0; P3 = 3 • Average waiting time （平均等待时间） : (6 + 0 + 3)/3 = 3 • Much better than previous case（比前例好得多）. • Convoy effect short process behind long process （此种结果产生是由于长进程先于短进程到达） P2 P3 P1 0 3 6 30