进程调度试验三

1、实验项目三进程调度实验目的1 .理解进程控制块和进程组织方式；2 .掌握时间片轮转调度算法实现处理机调度。二、实验内容1 .建立合理的PCB数据结构，建立含有8个进程结点的就绪队歹U,每个进程的要求运行时间随机产生，要求每个进程的要求运行时间不大于15。2 .设置时间片大小(36),使用时间片轮转调度算法实现处理机调度。三、源程序及运行结果源程序：#include<time.h>#include<stdio.h>#include<stdlib.h>#include<malloc.h>#defineNUM8#defineLENsizeof(PCB)

2、structPCBintname;intruntime;intrunedtime;intkilltime;structPCB*next;typedefstructPCBPCB;voidmain()inttimeslice=5;PCB*runqueue;PCB*top,*tail,*temp;inti;srand(int)time(0);for(i=0;i<NUM;i+)(temp=(PCB*)malloc(LEN);temp->name=i;temp->runtime=rand()%15;temp->runedtime=0;temp->next=NULL;temp

3、->killtime=0;if(i=0)(top=temp;tail=temp;else(tail->next=temp;tail=temp;printf("processname%d,runtime=%d,runedtime=%d,killtime=%dn",tail->name,tail->runtime,tail->runedtime,tail->killtime);printf(”*n");while(top!=NULL)runqueue=top;top=top->next;runqueue->next=NU

4、LL;runqueue->runtime=runqueue->runtime-timeslice;if(runqueue->runtime<=0)runqueue->killtime=runqueue->runtime+timeslice;runqueue->runedtime=runqueue->killtime+runqueue->runedtime;runqueue->runtime=runqueue->runedtime;printf("processname%d,runtime=%d,runedtime=%d

5、,killtime=%d(finished)n”,runqueue->name,runqueue->runtime,runqueue->runedtime,runqueue->killtime);else(runqueue->killtime=timeslice;runqueue->runedtime=runqueue->runedtime+runqueue->killtime;printf("processname%d,runtime=%d,runedtime=%d,killtime=%dn",runqueue->na

6、me,runqueue->runtime,runqueue->runedtime,runqueue->killtime);tail->next=runqueue;tail->next=tail;运行结果：（截图）。.Dsos-desktop:一文件(F)蝙斶(日查看(V)tSa(T)帮助出)os$os-desktop:*$PCB.c*oposos-desktop：-1*,/Ppoce5snameruntime=10Prunedtime=0rkilltinie=eprocessname1,runtime-7,runedtime=0rkilltime=6process

7、name2pnjntime=13,runedtinnrkilltprocessname3pruntime。runedtine=apkilltime=eprocessname4frunt11116=3,runedtime=,killtime=6processname5,runtime=14,runedtime=0rkilLtime=95nameB,runtime=3,runedtine=9,killtinie=9processname7,runtime=4rrunedtime=0rkilltime=6processnameSpruntime=5prunedtime=5rkilltime=5pro

8、cessname1,runtime=2Prunedtime=5,killtime=5processname2truntime=8Prunedtime=5fkiHtime=5processname3,runtime=2,runedt1016=2,kilLtime=lt(finished)processname4,runtime=3rrunedtime=3,killtinie=3(finished)processname5,runtimesrrunedtime=5,killtime=5processname6,runtime=3Fnjnedtime=3Fkilltime=3(finished)pr

9、ocessname7,runtime=A,runedtimeM,killtime=4(finished)processname7pruntime=8prunedtime=B,killtime=4(finishedosos-desktop：*$四、实验分析与总结对实验运行结果进行分析：如果时间片设置值过大或过小，会对进程的调度产生何种影响。1.答：时间片轮转算法调度的过程是首先取就绪队列的队首结点为运行队列的结点，修改就绪队列队首指针后移；然后调度运行队列结点，即运行队列结点的要求运行时间减去时间片时间；若修改后要求运行时间=0,则表示该进程结点运行完毕，修改进程结点的PCB信息，记录runtime,runedtime,killtime等信息，并将结点信息输出。否则，表示该进程结点未完成，记录runtime,runedtime,killtime等信息，将结点信息输出。并将该结点置于就绪队列的队尾，等待下次调度，同时修改