静态优先级调度算法

1、_ 成绩（五级制）：_武汉科技大学城市学院操作系统实验报告院 系 武汉科技的大学城市学院学生专业 信科年级 班 大三课程名称 操作系统实验题目 进程调度学生姓名 宋骋指导教师 郭冀生2013年 11 月 4 日实验二 进程调度一、实验目的进程是操作系统最重要的概念之一，进程调度又是操作系统核心的重要内容。通过该实验，要求同学们了解各进程在执行过程中的状态和参数的变化情况，以便于观察诸进程的调度过程。二、实验内容及要求 按剥夺式优先数法对三个进程P1,p2,p3进行模拟调度，各进程的优先数静态设置，其中P1的优先数最高，P3的优先数最低。每个进程都处于执行E(execute),就绪R(ready

2、)和等待W(wait)三种状态之一，并假定初始状态均为R.。三个进程有如下同步关系：P1因等待事件1被阻塞后由P2发现并唤醒之，P2因等待事件2被阻塞后由P3发现并唤醒之。当系统进入运行，在完成必要的初始化工作以后便进入进程调度，首先选择优先数最高的进程使其进入执行（分配CPU）。当执行进程因等待某个事件被阻塞或唤醒某个等待进程时，转入进程调度。如果被唤醒的进程的优先数大于现行的执行进程，则剥夺现行进程的执行权，而将CPU分配给被唤醒的进程。当系统处于死锁或三个进程都执行完毕时系统退出运行。系统中应用到如下数据结构：*进程控制块PCB；*信号量sem；*其它需要的数据结构。由自己设计。三、实验

3、原理及步骤 根据现代操作系统的特征1并发性（concurrence)；2共享性(sharing)；3虚拟性(virtual)；4异步性(asynchronism) 。模拟出进程在执行中的状态变化过程；体会进程申请资源、使用资源、归还资源；体会死锁。步骤（参考框图）4、算法和流程图可强占优先调度算法实现过程流程图（如下图）： 四、程序运行1 选择输入执行程序（如下图）2 可强占优先调度算法图（如下图）五.设计总结：通过该课程设计，加深了对系统进程调度机制的理解。在抢占方式中实践了“抢占” 必须遵循的原则：优先权原则。认识了几种进程调度算法的优缺点以及应用范围。加强C+的编程能力，实现类的封装。附

4、录：程序及注释（用红色黑体标注自己设计的函数）/进程PCB类和模拟cpu的进程类的声明#include <stdio.h>#include <stdlib.h>#include <windows.h>#include <conio.h>#include <stdlib.h>#include <stdio.h>#include <time.h>#include <io.h>#include <string.h>#define MAX_PHILOSOPHERS 3 /待测试的哲学家数#def

5、ine ZERO 48 /数字0的ASCII码#define DELAY rand()%25struct PCB char p_name20; int p_priority; int p_needTime; int p_runTime; char p_state;char deadlock(); struct PCB* next;void HighPriority();void deadlock();void Information();/形参的改变映射给实参 说白了就是实参传过去不用return 返回就可以把实参改变char Choice();struct PCB* SortList(PCB

6、* HL);int main(int argc,char *argv) Information(); char choice = Choice(); switch(choice) case '1': system("cls"); HighPriority(); break; case '2': system("cls"); void deadlock(); break; default: break; system("pause"); return 0;void Information() printf

7、("nn"); printf(" * n"); printf(" 模拟进程调度算法n"); printf(" * nnn"); printf("静态优先级调度算法"); printf("死锁问题"); printf("按回车键进入演示程序"); getchar(); system("cls");system("cls");char Choice() printf("nn"); printf(&qu

8、ot; * n"); printf(" 进程调度演示n"); printf(" * nnn"); printf(" 1.演示最高优先数优先算法。n"); printf(" 2.演示死锁问题。n"); printf(" 3.退出程序。nnnn"); printf(" 选择进程调度方法:"); printf("select a function(13):"); char ch = getchar(); return ch; system("

9、cls");void HighPriority() struct PCB *processes, *pt; /pt作为临时节点来创建链表 processes = pt = (struct PCB*)malloc(sizeof(struct PCB); for (int i = 1; i != 4; +i) struct PCB *p = (struct PCB*)malloc(sizeof(struct PCB); printf("进程号No.%d：n", i); printf("输入进程名："); scanf("%s",

10、p->p_name); printf("输入进程优先数："); scanf("%d", &p->p_priority); printf("输入进程运行时间："); scanf("%d", &p->p_needTime); p->p_runTime = 0; p->p_state = 'W' p->next = NULL; pt->next = p; pt = p; printf("nn"); getchar(); /接受回

11、车 /processes作为头结点来存储链表 processes = processes->next; int cases = 0; struct PCB *psorted = processes; while (1) +cases; pt = processes; /对链表按照优先数排序 /psorted用来存放排序后的链表 psorted = SortList(psorted); printf("The execute number: %dnn", cases); printf("* 当前正在运行的进程是：%sn", psorted->p

12、_name); psorted->p_state = 'R' printf("qname state super ndtime runtimen"); printf("%st%ct%dt%dt%dtnn", psorted->p_name, psorted->p_state, psorted->p_priority, psorted->p_needTime, psorted->p_runTime); pt->p_state = 'W' psorted->p_runTime+;

13、 psorted->p_priority-; printf("* 当前就绪状态的队列为：nn"); /pt指向已经排序的队列 pt = psorted->next; while (pt != NULL) printf("qname state super ndtime runtimen"); printf("%st%ct%dt%dt%dtnn", pt->p_name, pt->p_state, pt->p_priority, pt->p_needTime, pt->p_runTime); p

14、t = pt->next; /pt指向已经排序的链表，判断链表是否有已用时间啊等于需要时间的 pt = psorted; struct PCB *ap; ap = NULL; /ap指向pt的前一个节点 while (pt != NULL) if (pt->p_needTime = pt->p_runTime) if (ap = NULL) pt = psorted->next; psorted = pt; else ap->next = pt->next; ap = pt; pt = pt->next; if (psorted->next =

15、NULL) break; getchar(); struct PCB* SortList(PCB* HL) struct PCB* SL; SL = (struct PCB*)malloc(sizeof(struct PCB); SL = NULL; struct PCB* r = HL; while (r != NULL) struct PCB* t = r->next; struct PCB* cp = SL; struct PCB* ap = NULL; while (cp != NULL) if (r->p_priority > cp->p_priority)

16、break; else ap = cp; cp = cp->next; if (ap = NULL) r->next = SL; SL = r; else r->next = cp; ap->next = r; r = t; return SL;/HANDLE h_mutex_chopsticksMAX_PHILOSOPHERS; /互斥体数组，每根筷子需要一个互斥体int thread_numberMAX_PHILOSOPHERS=1,2,3;/定义死锁的个数/会产生死锁的哲学家线程int deadlock_philosopher(LPVOID data)int ph

17、ilosopher_number=*(int *)(data); /哲学家编号for(;)srand( (unsigned)time( NULL ) * ( philosopher_number+ 1) ); Sleep(DELAY); printf("%s%c%s%cn","Philosopher ",ZERO+philosopher_number," is waiting chopstick ",(ZERO+philosopher_number); WaitForSingleObject(h_mutex_chopsticksphi

18、losopher_number, INFINITE); printf("%s%c%s%cn","Philosopher ",ZERO+philosopher_number," got chopstick ",(ZERO+philosopher_number);Sleep(DELAY/4);printf("%s%c%s%cn","Philosopher ",ZERO+philosopher_number," is waiting chopstick ",(ZERO+(1+phi

19、losopher_number)%MAX_PHILOSOPHERS); WaitForSingleObject(h_mutex_chopsticks(1+philosopher_number)%MAX_PHILOSOPHERS), INFINITE); printf("%s%c%s%cn","Philosopher ",ZERO+philosopher_number," got chopstick ",(ZERO+(1+philosopher_number)%MAX_PHILOSOPHERS); printf("%s%c%s

20、n","Philosopher ",ZERO+philosopher_number," is eating."); Sleep(DELAY); ReleaseMutex(h_mutex_chopsticksphilosopher_number);printf("%s%c%s%cn","Philosopher ",ZERO+philosopher_number," released chopstick ",ZERO+philosopher_number); ReleaseMutex(h_

21、mutex_chopsticks(1+philosopher_number)%MAX_PHILOSOPHERS);printf("%s%c%s%cn","Philosopher ",ZERO+philosopher_number," released chopstick ",(ZERO+(1+philosopher_number)%MAX_PHILOSOPHERS); Sleep(DELAY); / end forreturn 0;/死锁时的初始化程序void deadlock()char choice;int i=0;HANDLE

22、h_threadMAX_PHILOSOPHERS;printf("可能出现死锁的哲学家就餐问题n");for(i=0;i<MAX_PHILOSOPHERS;i+)h_mutex_chopsticksi=CreateMutex(NULL,FALSE,NULL);for(i=0;i<MAX_PHILOSOPHERS;i+)h_threadi=CreateThread(NULL,0,(LPTHREAD_START_ROUTINE)(deadlock_philosopher),&thread_numberi,0,NULL);WaitForMultipleObje

23、cts(MAX_PHILOSOPHERS,h_thread,TRUE,-1);dochoice=(char)getch();while( choice!='2');system("cls");deadlock();printf("nPress any key to return to main menu.");getch();system("cls");/通过按序分配资源预防死锁的哲学家线程int ordered_allocation_philosopher(LPVOID data)int philosopher_nu

24、mber=*(int *)(data);for(;)srand( (unsigned)time( NULL ) * ( philosopher_number+ 1) ); Sleep(DELAY);if(philosopher_number=MAX_PHILOSOPHERS-1) printf("%s%c%s%cn","Philosopher ",ZERO+philosopher_number," is waiting chopstick ",(ZERO+(1+philosopher_number)%MAX_PHILOSOPHERS)

25、; WaitForSingleObject(h_mutex_chopsticks(1+philosopher_number)%MAX_PHILOSOPHERS, INFINITE); Sleep(DELAY/4); printf("%s%c%s%cn","Philosopher ",ZERO+philosopher_number," is waiting chopstick ",ZERO+philosopher_number); WaitForSingleObject(h_mutex_chopsticksphilosopher_num

26、ber, INFINITE);else printf("%s%c%s%cn","Philosopher ",ZERO+philosopher_number," is waiting chopstick ",ZERO+philosopher_number); WaitForSingleObject(h_mutex_chopsticksphilosopher_number, INFINITE); Sleep(DELAY/4); printf("%s%c%s%cn","Philosopher ",ZE

27、RO+philosopher_number," is waiting chopstick ",ZERO+(1+philosopher_number)%MAX_PHILOSOPHERS); WaitForSingleObject(h_mutex_chopsticks(1+philosopher_number)%MAX_PHILOSOPHERS, INFINITE); printf("%s%c%sn","Philosopher ",ZERO+philosopher_number," is eating."); Sleep(DELAY); printf("%s%c%s%cn","Philosopher ",ZERO+philosopher_number," is releasing chopstick ",ZERO+philosopher_number);