(1)先来先服务调度算法;(2)短作业优先调度算法;(3)剥夺式优先级调度算法。
时间: 2023-11-27 09:04:05 浏览: 157
(1) 先来先服务调度算法(First Come First Serve,FCFS)是一种最简单的调度算法,按照作业提交的先后顺序进行调度。它的优点是实现简单、公平性好,缺点是平均等待时间较长,不适用于短作业和交互式系统。
(2) 短作业优先调度算法(Shortest Job First,SJF)是按照作业所需的处理时间来安排作业的执行顺序,优先考虑需要执行时间短的作业。它的优点是平均等待时间短,适用于大量短作业的系统,缺点是无法预测作业的执行时间,可能导致长作业等待时间过长。
(3) 剥夺式优先级调度算法(Preemptive Priority Scheduling)是在短作业优先调度算法基础上增加了优先级的概念,当优先级高的作业到达时,会抢占正在执行的作业,重新安排执行顺序。它的优点是可以提高紧急任务的优先级,缺点是可能导致低优先级作业长时间等待,不适用于交互式系统。
相关问题
实现进程调度1—静态非剥夺式优先级调度计算平均作业周转时间的代码
以下是一个简单的静态非剥夺式优先级调度算法的代码示例,用于计算平均作业周转时间:
```
#include <stdio.h>
#include <stdlib.h>
#define MAX_JOBS 10
typedef struct {
int pid; // 进程ID
int priority; // 进程优先级
int arrival; // 进程到达时间
int burst; // 进程执行时间
} Job;
int main() {
Job jobs[MAX_JOBS];
int num_jobs, i, j;
float avg_turnaround = 0.0;
// 输入作业信息
printf("请输入作业数(最多%d个):", MAX_JOBS);
scanf("%d", &num_jobs);
for (i = 0; i < num_jobs; i++) {
printf("请输入第%d个作业的信息(pid, 优先级, 到达时间, 执行时间):", i + 1);
scanf("%d %d %d %d", &jobs[i].pid, &jobs[i].priority, &jobs[i].arrival, &jobs[i].burst);
}
// 静态非剥夺式优先级调度算法
Job temp;
for (i = 0; i < num_jobs - 1; i++) {
for (j = i + 1; j < num_jobs; j++) {
if (jobs[i].priority < jobs[j].priority) {
temp = jobs[i];
jobs[i] = jobs[j];
jobs[j] = temp;
}
}
}
// 计算平均作业周转时间
int current_time = 0;
for (i = 0; i < num_jobs; i++) {
int turnaround = current_time + jobs[i].burst - jobs[i].arrival;
avg_turnaround += turnaround;
current_time += jobs[i].burst;
}
avg_turnaround /= num_jobs;
// 输出结果
printf("平均作业周转时间为:%.2f\n", avg_turnaround);
return 0;
}
```
该代码首先输入作业信息,然后使用静态非剥夺式优先级调度算法对作业进行排序,接着计算每个作业的周转时间并计算平均值,最后输出结果。请注意,该代码仅为示例,可能需要根据具体情况进行修改和优化。
java实现进程调度1—静态非剥夺式优先级调度计算平均作业周转时间的代码
以下是 Java 实现进程调度1—静态非剥夺式优先级调度计算平均作业周转时间的代码:
```java
import java.util.*;
class Process {
int pid; // 进程 ID
int bt; // 进程的运行时间
int at; // 进程的到达时间
int priority; // 进程的优先级
public Process(int pid, int bt, int at, int priority) {
this.pid = pid;
this.bt = bt;
this.at = at;
this.priority = priority;
}
}
public class StaticPriorityNonPreemptive {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.print("Enter the number of processes: ");
int n = sc.nextInt();
Process[] processes = new Process[n];
for (int i = 0; i < n; i++) {
System.out.println("Enter the details of process " + (i+1) + ":");
System.out.print("Burst Time: ");
int bt = sc.nextInt();
System.out.print("Arrival Time: ");
int at = sc.nextInt();
System.out.print("Priority: ");
int priority = sc.nextInt();
processes[i] = new Process(i+1, bt, at, priority);
}
// Sort the processes based on their arrival time
Arrays.sort(processes, (p1, p2) -> p1.at - p2.at);
int[] ct = new int[n]; // Completion Time
int[] tat = new int[n]; // Turnaround Time
int[] wt = new int[n]; // Waiting Time
// Initialize the first process
ct[0] = processes[0].at + processes[0].bt;
tat[0] = ct[0] - processes[0].at;
wt[0] = tat[0] - processes[0].bt;
// Calculate completion time, turnaround time and waiting time for each process
for (int i = 1; i < n; i++) {
int shortestJobIndex = i;
for (int j = i; j < n; j++) {
if (processes[j].priority < processes[shortestJobIndex].priority) {
shortestJobIndex = j;
}
}
Process shortestJob = processes[shortestJobIndex];
processes[shortestJobIndex] = processes[i];
processes[i] = shortestJob;
ct[i] = ct[i-1] + processes[i].bt;
tat[i] = ct[i] - processes[i].at;
wt[i] = tat[i] - processes[i].bt;
}
// Calculate average turnaround time and waiting time
double avgTAT = Arrays.stream(tat).average().getAsDouble();
double avgWT = Arrays.stream(wt).average().getAsDouble();
// Print the results
System.out.println("\nProcess\tBurst Time\tArrival Time\tPriority\tCompletion Time\tTurnaround Time\tWaiting Time");
for (int i = 0; i < n; i++) {
System.out.println(processes[i].pid + "\t\t" + processes[i].bt + "\t\t" + processes[i].at + "\t\t" + processes[i].priority + "\t\t" + ct[i] + "\t\t" + tat[i] + "\t\t" + wt[i]);
}
System.out.printf("\nAverage Turnaround Time: %.2f\n", avgTAT);
System.out.printf("Average Waiting Time: %.2f\n", avgWT);
}
}
```
该代码使用了静态非剥夺式优先级调度算法,其中程序会首先按照到达时间排序,然后按照进程的优先级进行排序。程序会根据这个排序顺序依次完成每个进程,并计算出每个进程的完成时间、周转时间和等待时间。最后,程序会输出每个进程的各项数据以及平均周转时间和等待时间。
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