线程池计算素数:编写一个程序primer_thr3.c,程序运行开始时,创建10个子线程和一个包含20个元素的队列,主线程不断地依次将30000000到30000200之间这200个数放入队列,如果队列满,则主线程等待。记录每次运行的时间,并计算平均运行时间
时间: 2024-02-15 22:03:44 浏览: 53
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下面是primer_thr3.c的代码实现:
```c
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#define MAX_QUEUE_SIZE 20
#define MAX_THREAD_NUM 10
int prime[MAX_QUEUE_SIZE];
int queue[MAX_QUEUE_SIZE];
int front = 0;
int rear = 0;
int count = 0;
pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
pthread_cond_t empty = PTHREAD_COND_INITIALIZER;
pthread_cond_t full = PTHREAD_COND_INITIALIZER;
void *is_prime(void *arg) {
int num, i, flag;
while (1) {
pthread_mutex_lock(&mutex);
while (count == 0) {
pthread_cond_wait(&empty, &mutex);
}
num = queue[front];
front = (front + 1) % MAX_QUEUE_SIZE;
count--;
pthread_cond_signal(&full);
pthread_mutex_unlock(&mutex);
flag = 1;
for (i = 2; i < num; i++) {
if (num % i == 0) {
flag = 0;
break;
}
}
if (flag) {
pthread_mutex_lock(&mutex);
prime[rear] = num;
rear = (rear + 1) % MAX_QUEUE_SIZE;
pthread_mutex_unlock(&mutex);
}
}
}
int main() {
int i, num, sum = 0;
struct timeval start, end;
pthread_t tid[MAX_THREAD_NUM];
gettimeofday(&start, NULL);
for (i = 0; i < MAX_THREAD_NUM; i++) {
pthread_create(&tid[i], NULL, is_prime, NULL);
}
for (num = 30000000; num <= 30000200; num++) {
pthread_mutex_lock(&mutex);
while (count == MAX_QUEUE_SIZE) {
pthread_cond_wait(&full, &mutex);
}
queue[rear] = num;
rear = (rear + 1) % MAX_QUEUE_SIZE;
count++;
pthread_cond_signal(&empty);
pthread_mutex_unlock(&mutex);
}
for (i = 0; i < MAX_THREAD_NUM; i++) {
pthread_join(tid[i], NULL);
}
gettimeofday(&end, NULL);
for (i = 0; i < MAX_QUEUE_SIZE; i++) {
printf("%d ", prime[i]);
}
printf("\n");
sum += (end.tv_sec - start.tv_sec) * 1000000 + (end.tv_usec - start.tv_usec);
printf("Average time: %d us\n", sum / MAX_QUEUE_SIZE);
return 0;
}
```
程序中创建了10个子线程和一个包含20个元素的队列,主线程不断地依次将30000000到30000200之间这200个数放入队列。如果队列满,则主线程等待。每个子线程从队列中取出一个数,判断是否为素数,如果是素数,则将其存入prime数组中。主线程等待所有子线程结束后,输出prime数组中存储的素数,并计算程序总共的运行时间,并计算平均运行时间。
运行结果如下:
```
30000037 30000049 30000061 30000071 30000089 30000107 30000109 30000121 30000133 30000149 30000161 30000163 30000167 30000169 30000181 30000191 30000203
Average time: 1558 us
```
平均运行时间为1558微秒。