用C语言写出短作业优先调度算法核心思路
时间: 2023-11-17 08:05:45 浏览: 66
短作业优先调度算法的核心思路是优先调度执行时间短的作业,先处理短的作业,避免长作业占用CPU,提高系统的吞吐率和响应速度。具体实现步骤包括:
1. 对于所有作业,计算出其执行时间。
2. 按照执行时间从小到大排序。
3. 执行时间最短的作业先被调度,直到作业执行完毕后进入下一轮调度。
4. 如果有多个作业的执行时间相同,则根据作业的到达顺序进行调度。
这样就能够尽可能地利用CPU资源,提高系统的效率。
相关问题
写一个C语言版本的模拟实现短作业优先调度算法实验代码
以下是一个简单的短作业优先调度算法的C语言代码实现。
```
#include <stdio.h>
#define MAX_PROCESS 10
struct process {
int id;
int arrival_time;
int burst_time;
int waiting_time;
int turnaround_time;
int remaining_time;
int completed;
};
int main() {
int n, time = 0, total_waiting_time = 0, total_turnaround_time = 0;
struct process processes[MAX_PROCESS], *current_process = NULL;
printf("Enter the number of processes: ");
scanf("%d", &n);
// Input process info
for (int i = 0; i < n; i++) {
printf("Enter arrival time and burst time for process %d: ", i + 1);
scanf("%d %d", &processes[i].arrival_time, &processes[i].burst_time);
processes[i].id = i + 1;
processes[i].waiting_time = 0;
processes[i].turnaround_time = 0;
processes[i].remaining_time = processes[i].burst_time;
processes[i].completed = 0;
}
// Schedule processes
while (1) {
int shortest_time = 99999;
for (int i = 0; i < n; i++) {
if (processes[i].arrival_time <= time && processes[i].completed == 0) {
if (processes[i].remaining_time < shortest_time) {
shortest_time = processes[i].remaining_time;
current_process = &processes[i];
}
}
}
if (current_process == NULL) {
time++;
continue;
}
current_process->remaining_time--;
shortest_time--;
if (current_process->remaining_time == 0) {
current_process->completed = 1;
current_process->turnaround_time = time + 1 - current_process->arrival_time;
current_process->waiting_time = current_process->turnaround_time - current_process->burst_time;
total_turnaround_time += current_process->turnaround_time;
total_waiting_time += current_process->waiting_time;
current_process = NULL;
}
time++;
if (current_process == NULL && time != 0) {
break;
}
}
// Output process info
printf("\nProcess\tArrival Time\tBurst Time\tWaiting Time\tTurnaround Time\n");
for (int i = 0; i < n; i++) {
printf("%d\t\t%d\t\t%d\t\t%d\t\t%d\n", processes[i].id, processes[i].arrival_time, processes[i].burst_time, processes[i].waiting_time, processes[i].turnaround_time);
}
printf("\nAverage Waiting Time: %.2f", (float)total_waiting_time / n);
printf("\nAverage Turnaround Time: %.2f", (float)total_turnaround_time / n);
return 0;
}
```
该代码首先要求用户输入进程数量以及每个进程的到达时间和运行时间。然后,它使用短作业优先调度算法来模拟进程的执行过程,并计算出平均等待时间和平均周转时间。最后,它将所有进程的信息以表格形式输出。
用C语言写出关于采用非抢占式高优先权的优先级调度算法
好的,关于采用非抢占式高优先权的优先级调度算法的C语言实现,以下是一段参考代码:
```c
#include <stdio.h>
// 定义进程结构体
struct process {
int pid; // 进程ID
int priority; // 优先级
int burst_time; // 运行时间
};
void non_preemptive_priority_scheduling(struct process *procs, int n) {
int i, j;
struct process temp;
// 根据优先级对进程进行排序(从大到小)
for (i = 0; i < n - 1; i++) {
for (j = i + 1; j < n; j++) {
if (procs[i].priority < procs[j].priority) {
temp = procs[i];
procs[i] = procs[j];
procs[j] = temp;
}
}
}
// 按顺序依次执行进程
printf("进程ID\t优先级\t运行时间\t\n");
for (i = 0; i < n; i++) {
printf("%d\t%d\t%d\t\n", procs[i].pid, procs[i].priority, procs[i].burst_time);
}
}
int main() {
int i, n;
struct process procs[100];
// 输入进程数量n及每个进程的信息
printf("请输入进程数量n:");
scanf("%d", &n);
for (i = 0; i < n; i++) {
printf("请输入进程%d的ID, 优先级和运行时间:", i + 1);
scanf("%d %d %d", &procs[i].pid, &procs[i].priority, &procs[i].burst_time);
}
// 使用非抢占式高优先权算法进行进程调度
non_preemptive_priority_scheduling(procs, n);
return 0;
}
```
希望这段代码能够帮助你。