使用C语言模拟操作系统实现时间片轮转调度算法 并模拟生产者消费者进程实现同步与互斥操作
时间: 2024-02-19 22:58:20 浏览: 122
时间片轮转算法和优先级调度算法-C语言模拟实现-收藏.doc
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首先,时间片轮转调度算法是一种常见的进程调度算法,它的实现基于一个时间片的概念,每个进程被分配一个时间片,当时间片用完后,系统会强制切换到下一个就绪进程。以下是使用 C 语言实现时间片轮转调度算法的示例代码:
```c
#include <stdio.h>
#define QUANTUM 2 // 定义时间片长度为 2
struct process {
int pid;
int burst_time;
int remaining_time;
};
int main() {
int n, i, j;
struct process p[10];
printf("Enter the number of processes: ");
scanf("%d", &n);
for (i = 0; i < n; i++) {
printf("Enter the burst time for process %d: ", i + 1);
scanf("%d", &p[i].burst_time);
p[i].pid = i + 1;
p[i].remaining_time = p[i].burst_time;
}
printf("\nProcess\tBurst Time\n");
for (i = 0; i < n; i++) {
printf("%d\t%d\n", p[i].pid, p[i].burst_time);
}
printf("\n");
int time = 0;
int flag = 0;
while (1) {
flag = 0;
for (i = 0; i < n; i++) {
if (p[i].remaining_time > 0) {
flag = 1;
if (p[i].remaining_time > QUANTUM) {
time += QUANTUM;
p[i].remaining_time -= QUANTUM;
printf("Process %d executed for %d seconds\n", p[i].pid, QUANTUM);
} else {
time += p[i].remaining_time;
printf("Process %d executed for %d seconds\n", p[i].pid, p[i].remaining_time);
p[i].remaining_time = 0;
}
}
}
if (flag == 0) {
break;
}
}
printf("\nTotal execution time: %d seconds\n", time);
return 0;
}
```
接下来,我们来模拟生产者消费者进程实现同步与互斥操作。生产者消费者问题是一种经典的线程同步问题,它涉及两种类型的进程:生产者和消费者。生产者进程负责生产数据,而消费者进程负责消费数据。为了防止生产者和消费者之间的竞争条件,我们需要使用同步和互斥机制。以下是使用 C 语言模拟生产者消费者进程的示例代码:
```c
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#define BUFFER_SIZE 10
int buffer[BUFFER_SIZE];
int count = 0;
int in = 0;
int out = 0;
pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
pthread_cond_t full = PTHREAD_COND_INITIALIZER;
pthread_cond_t empty = PTHREAD_COND_INITIALIZER;
void *producer(void *arg) {
int i;
for (i = 0; i < 20; i++) {
pthread_mutex_lock(&mutex);
while (count == BUFFER_SIZE) {
pthread_cond_wait(&empty, &mutex);
}
buffer[in] = i;
printf("Produced item %d\n", buffer[in]);
in = (in + 1) % BUFFER_SIZE;
count++;
pthread_cond_signal(&full);
pthread_mutex_unlock(&mutex);
}
pthread_exit(NULL);
}
void *consumer(void *arg) {
int i;
for (i = 0; i < 20; i++) {
pthread_mutex_lock(&mutex);
while (count == 0) {
pthread_cond_wait(&full, &mutex);
}
int item = buffer[out];
printf("Consumed item %d\n", item);
out = (out + 1) % BUFFER_SIZE;
count--;
pthread_cond_signal(&empty);
pthread_mutex_unlock(&mutex);
}
pthread_exit(NULL);
}
int main() {
pthread_t producer_thread, consumer_thread;
pthread_create(&producer_thread, NULL, producer, NULL);
pthread_create(&consumer_thread, NULL, consumer, NULL);
pthread_join(producer_thread, NULL);
pthread_join(consumer_thread, NULL);
return 0;
}
```
在这个示例中,我们使用了互斥锁和条件变量来实现同步和互斥操作。生产者进程通过互斥锁保护共享缓冲区,并使用条件变量来通知消费者进程缓冲区已经被更新。消费者进程也通过互斥锁保护共享缓冲区,并使用条件变量来通知生产者进程缓冲区已经被消费。这样可以保证生产者和消费者之间的竞争条件得到有效的解决。
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