繼上一篇C版本WEB服務器開發之線程池開發

經過線程池來處理web服務器端的數據處理和接收，會使服務器端的效率顯著提高。

經過隊列工廠生產和消費的模型，來編寫線程池。

線程池中每個線程的結構以下：

typedef struct worker{
	void *(*process)(void *arg);
	void *arg;
	struct worker *next;
}Thread_worker;

線程池的結構以下：

typedef struct{
	pthread_mutex_t queue_lock;
	pthread_cond_t queue_ready;

	Thread_worker *queue_head;

	int shutdown;
	pthread_t *threadID;
	int max_thread_num;
	int cur_queue_size;
}Thread_pool;

線程初始化：

void pool_init(int max_thread_num){
	pool = (Thread_pool*) malloc(sizeof(Thread_pool));
	pthread_mutex_init(&(pool->queue_lock), NULL);
	pthread_cond_init(&(pool->queue_ready), NULL);

	pool->queue_head = NULL;

	pool->max_thread_num = max_thread_num;
	pool->cur_queue_size = 0;

	pool->shutdown = 0;

	pool->threadID = (pthread_t *)malloc(max_thread_num *sizeof(pthread_t));

	int i = 0;
	for (i = 0; i < max_thread_num; i++){
		pthread_create(&(pool->threadID[i]), NULL, thread_routine, NULL);
	}
}

向線程池內添加任務隊列以下：

int pool_add_worker(void *(*process)(void *arg), void *arg){
	Thread_worker *newworker = (Thread_worker *)malloc(sizeof(Thread_worker));
	newworker->process = process;
	newworker->arg = arg;
	newworker->next = NULL;

	pthread_mutex_lock(&(pool->queue_lock));

	Thread_worker *member = pool->queue_head;
	if (member != NULL){
		while (member->next != NULL)
			member = member->next;
		member->next = newworker;
	}else{
		pool->queue_head = newworker;
	}

	assert(pool->queue_head != NULL);

	pool->cur_queue_size++;
	pthread_mutex_unlock(&(pool->queue_lock));

	pthread_cond_signal(&(pool->queue_ready));
	return 0;
}

線程週期化處理和循環：

void *thread_routine(void *arg){
	printf("starting thread 0x%x\n", (unsigned int)pthread_self());
	while(1){
		pthread_mutex_lock(&(pool->queue_lock));

		while(pool->cur_queue_size == 0 && !pool->shutdown){
			printf("thread 0x%x is waiting\n", (unsigned int)pthread_self());
			pthread_cond_wait(&(pool->queue_ready), &(pool->queue_lock));
		}

		if (pool->shutdown){
			pthread_mutex_unlock(&(pool->queue_lock));
			printf("thread 0x%x will exit\n", (unsigned int)pthread_self());
			pthread_exit(NULL);
		}

		printf("thread 0x%x is starting to work\n", (unsigned int)pthread_self());

		assert(pool->cur_queue_size != 0);
		assert(pool->queue_head != NULL);

		pool->cur_queue_size--;
		Thread_worker *worker = pool->queue_head;
		pool->queue_head = worker->next;
		pthread_mutex_unlock(&(pool->queue_lock));

		(*(worker->process))(worker->arg);
		free(worker);
		worker = NULL;
	}

	pthread_exit(NULL);
}

至此線程池的操做簡單的完成了。

Comming soon.....