操作系统实验九

1、精选优质文档-倾情为你奉上学号E 专业计算机科学与技术 姓名施飞宇实验日期2018/12/20 教师签字 成绩实验报告【实验名称】最低松弛度优先调度算法【实验目的】1. 学习最低松弛度算法思想。2. 用代码实现改算法，解决最低松弛度优先调度问题。【实验原理】最低松弛度优先（LLF）算法是根据任务紧急（或松弛）的程度，来确定任务的优先级。任务的紧急程度愈高，为该任务所赋予的优先级就愈高，使之优先执行。在实现该算法时要求系统中有一个按松弛度排序的实时任务就绪队列，松弛度最低的任务排在队列最前面，被优先调度。松弛度的计算方法如下： 任务的松弛度=必须完成的时间-其本身的运行时间-当前时间&

2、#160;其中其本身运行的时间指任务运行结束还需多少时间，如果任务已经运行了一部分，则： 任务松弛度=任务的处理时间-任务已经运行的时间 当前时间【实验内容】数据结构：本实验进程采用结构体来存储线信息，采用结构体数组来存储进程序列。进程结构定义如下：typedef structint start;/进程申请服务开始时间int over;/进程截止时间int survey1;/需要服务总时间int survey2;/已经服务时间int songchi;/松弛度int label;/等于0未被处理，等于1已经被处理完毕pcb;程序流程图：程序代码：%2018/12/20 笃行南楼 A20

3、2 E 施飞宇#include "iostream"#include <stdio.h>using namespace std;typedef structint start;/进程申请服务开始时间int over;/进程截止时间int survey1;/需要服务总时间int survey2;/已经服务时间int songchi;/松弛度int label;/等于0未被处理，等于1已经被处理完毕pcb;void pcb_A(pcb * A,int n)/A进程创建函数 int i; for(i=0;i<n+1;i+) Ai.start=i*20; Ai.s

4、urvey2=0; Ai.label=0; Ai.songchi=10; Ai.survey1=10; Ai.over=Ai.start+20; if(i!=n) cout<<"A"<<i+1<<"到达时间"<<Ai.start<<" 截止时间"<<Ai.over<<endl; void pcb_B(pcb * B,int n)/B进程创建函数 int i; for(i=0;i<n+1;i+) Bi.start=i*50; Bi.survey2=

5、0; Bi.label=0; Bi.songchi=25; Bi.survey1=25; Bi.over=Bi.start+50; if(i!=n) cout<<"B"<<i+1<<"到达时间"<<Bi.start<<" 截止时间"<<Bi.over<<endl; int test(pcb *X,int n,int time) int i,j; for(i=0;i<n;i+) if(Xi.label=0&&Xi.start<

6、=time) Xi.songchi=Xi.over-(Xi.survey1-Xi.survey2)-time; return i; return -1;void run_AB(pcb *A,int n1,pcb *B,int n2) int time; int ai,bi,ka,kb; int max_time; int AB=1; int label=0; if(n1*20>=n2*50) max_time=n1*20; else max_time=n2*50; cout<<"时间 "<<" A"<<"

7、;截止时间 "<<" 服务时间 "<<" 松弛度 "<<"B 截止时间 "<<" 服务时间 "<<" 松弛度 "<<endl; cout<<"0"<<" A"<<"1"<<" "<<A0.over<<" "<<A0.survey2&l

8、t;<" "<<A0.songchi<<" B"<<"1"<<" "<<B0.over<<" "<<B0.survey2<<" "<<B0.songchi<<endl; for(time=0;time<=max_time;time=time + 1) ka = test(A,n1,time); if(ka = -1) ai=ai+1; else

9、ai=ka; / cout<<"A"<<ai+1<<" "<<Aai.songchi<<endl; kb=test(B,n2,time); if(kb=-1) bi=bi+1; else bi=kb; / cout<<"B"<<bi+1<<" "<<Bbi.songchi<<endl; if(Bbi.songchi=0|ka=-1|label=1) AB=0;label=0; if(Aai.son

10、gchi=0|kb=-1|label=2) AB=1;label=0; if(AB=1&&ai<n1) if(Aai.survey1=(+Aai.survey2) cout<<time+1<<" A"<<ai+1<<" "<<Aai.over<<" "<<Aai.survey2<<" "<<Aai.songchi/5*5<<" B"<<bi+1

11、<<" "<<Bbi.over<<" "<<Bbi.survey2<<" "<<Bbi.songchi/5*5<<endl; cout<<time+1<<" A"<<ai+1<<"进程结束"<<endl; Aai.label=1; label=1; else if(time+1)%5=0) cout<<time+1<<"

12、 A"<<ai+1<<" "<<Aai.over<<" "<<Aai.survey2<<" "<<Aai.songchi/5*5<<" B"<<bi+1<<" "<<Bbi.over<<" "<<Bbi.survey2<<" "<<Bbi.songchi/5*5<

13、<endl; if(AB=0&&bi<n2) if(Bbi.survey1=(+Bbi.survey2) cout<<time+1<<" A"<<ai+1<<" "<<Aai.over<<" "<<Aai.survey2<<" "<<Aai.songchi/5*5<<" B"<<bi+1<<" "<&

14、lt;Bbi.over<<" "<<Bbi.survey2<<" "<<Bbi.songchi/5*5<<endl; cout<<time+1<<" B"<<bi+1<<"进程结束"<<endl; Bbi.label=1; label=2; else if(time+1)%5=0) cout<<time+1<<" A"<<ai+1<&l

15、t;" "<<Aai.over<<" "<<Aai.survey2<<" "<<Aai.songchi/5*5<<" B"<<bi+1<<" "<<Bbi.over<<" "<<Bbi.survey2<<" "<<Bbi.songchi/5*5<<endl; if(kb=-1) bi=bi-1; if(ka=-1) ai=ai-1; int main() int n1,n2; pcb A10,B10; cout<<"输入A进程个数"<<