/*** threadpool.h ***/ #ifndef __THREADPOOL_H_ #define __THREADPOOL_H_ typedef struct threadpool_t threadpool_t; /** * @function threadpool_create * @descCreates a threadpool_t object. * @param thr_num thread num * @param max_thr_num max thread size * @param queue_max_size size of the queue. * @return a newly created thread pool or NULL */ threadpool_t *threadpool_create(int min_thr_num, int max_thr_num, int queue_max_size); /** * @function threadpool_add * @desc add a new task in the queue of a thread pool * @param pool Thread pool to which add the task. * @param function Pointer to the function that will perform the task. * @param argument Argument to be passed to the function. * @return 0 if all goes well,else -1 */ int threadpool_add(threadpool_t *pool, void*(*function)(void *arg), void *arg); /** * @function threadpool_destroy * @desc Stops and destroys a thread pool. * @param pool Thread pool to destroy. * @return 0 if destory success else -1 */ int threadpool_destroy(threadpool_t *pool); /** * @desc get the thread num * @pool pool threadpool * @return # of the thread */ int threadpool_all_threadnum(threadpool_t *pool); /** * desc get the busy thread num * @param pool threadpool * return # of the busy thread */ int threadpool_busy_threadnum(threadpool_t *pool); #endif
/***
threadpool.c
***/
#include <stdlib.h>
#include <pthread.h>
#include <unistd.h>
#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <signal.h>
#include <errno.h>
#include "threadpool.h"
#define DEFAULT_TIME 10 /*10s检测一次*/
#define MIN_WAIT_TASK_NUM 10 /*如果queue_size > MIN_WAIT_TASK_NUM 添加新的线程到线程池*/
#define DEFAULT_THREAD_VARY 10 /*每次创建和销毁线程的个数*/
#define true 1
#define false 0
typedef struct {
void *(*function)(void *); /* 函数指针，回调函数 */
void *arg; /* 上面函数的参数 */
} threadpool_task_t; /* 各子线程任务结构体 */
/* 描述线程池相关信息 */
struct threadpool_t {
pthread_mutex_t lock; /* 用于锁住本结构体 */
pthread_mutex_t thread_counter; /* 记录忙状态线程个数de琐 -- busy_thr_num */
pthread_cond_t queue_not_full; /* 当任务队列满时，添加任务的线程阻塞，等待此条件变量 */
pthread_cond_t queue_not_empty; /* 任务队列里不为空时，通知等待任务的线程 */
pthread_t *threads; /* 存放线程池中每个线程的tid。数组 */
pthread_t adjust_tid; /* 存管理线程tid */
threadpool_task_t *task_queue; /* 任务队列 */
int min_thr_num; /* 线程池最小线程数 */
int max_thr_num; /* 线程池最大线程数 */
int live_thr_num; /* 当前存活线程个数 */
int busy_thr_num; /* 忙状态线程个数 */
int wait_exit_thr_num; /* 要销毁的线程个数 */
int queue_front; /* task_queue队头下标 */
int queue_rear; /* task_queue队尾下标 */
int queue_size; /* task_queue队中实际任务数 */
int queue_max_size; /* task_queue队列可容纳任务数上限 */
int shutdown; /* 标志位，线程池使用状态，true或false */
};
/**
* @function void *threadpool_thread(void *threadpool)
* @desc the worker thread
* @param threadpool the pool which own the thread
*/
void *threadpool_thread(void *threadpool);
/**
* @function void *adjust_thread(void *threadpool);
* @desc manager thread
* @param threadpool the threadpool
*/
void *adjust_thread(void *threadpool);
/**
* check a thread is alive
*/
int is_thread_alive(pthread_t tid);
int threadpool_free(threadpool_t *pool);
threadpool_t *threadpool_create(int min_thr_num, int max_thr_num, int queue_max_size)
{
int i;
threadpool_t *pool = NULL;
do {
if((pool = (threadpool_t *)malloc(sizeof(threadpool_t))) == NULL) {
printf("malloc threadpool fail");
break;/*跳出do while*/
}
pool->min_thr_num = min_thr_num;
pool->max_thr_num = max_thr_num;
pool->busy_thr_num = 0;
pool->live_thr_num = min_thr_num; /* 活着的线程数 初值=最小线程数 */
pool->queue_size = 0; /* 有0个产品 */
pool->queue_max_size = queue_max_size;
pool->queue_front = 0;
pool->queue_rear = 0;
pool->shutdown = false; /* 不关闭线程池 */
/* 根据最大线程上限数， 给工作线程数组开辟空间, 并清零 */
pool->threads = (pthread_t *)malloc(sizeof(pthread_t)*max_thr_num);
if (pool->threads == NULL) {
printf("malloc threads fail");
break;
}
memset(pool->threads, 0, sizeof(pthread_t)*max_thr_num);
/* 队列开辟空间 */
pool->task_queue = (threadpool_task_t *)malloc(sizeof(threadpool_task_t)*queue_max_size);
if (pool->task_queue == NULL) {
printf("malloc task_queue fail");
break;
}
/* 初始化互斥琐、条件变量 */
if (pthread_mutex_init(&(pool->lock), NULL) != 0
|| pthread_mutex_init(&(pool->thread_counter), NULL) != 0
|| pthread_cond_init(&(pool->queue_not_empty), NULL) != 0
|| pthread_cond_init(&(pool->queue_not_full), NULL) != 0)
{
printf("init the lock or cond fail");
break;
}
/* 启动 min_thr_num 个 work thread */
for (i = 0; i < min_thr_num; i++) {
pthread_create(&(pool->threads[i]), NULL, threadpool_thread, (void *)pool);/*pool指向当前线程池*/
printf("start thread 0x%x...\n", (unsigned int)pool->threads[i]);
}
pthread_create(&(pool->adjust_tid), NULL, adjust_thread, (void *)pool);/* 启动管理者线程 */
return pool;
} while (0);
threadpool_free(pool); /* 前面代码调用失败时，释放poll存储空间 */
return NULL;
}
/* 向线程池中 添加一个任务 */
int threadpool_add(threadpool_t *pool, void*(*function)(void *arg), void *arg)
{
pthread_mutex_lock(&(pool->lock));
/* ==为真，队列已经满， 调wait阻塞 */
while ((pool->queue_size == pool->queue_max_size) && (!pool->shutdown)) {
pthread_cond_wait(&(pool->queue_not_full), &(pool->lock));
}
if (pool->shutdown) {
pthread_mutex_unlock(&(pool->lock));
}
/* 清空 工作线程 调用的回调函数 的参数arg */
if (pool->task_queue[pool->queue_rear].arg != NULL) {
free(pool->task_queue[pool->queue_rear].arg);
pool->task_queue[pool->queue_rear].arg = NULL;
}
/*添加任务到任务队列里*/
pool->task_queue[pool->queue_rear].function = function;
pool->task_queue[pool->queue_rear].arg = arg;
pool->queue_rear = (pool->queue_rear + 1) % pool->queue_max_size; /* 队尾指针移动, 模拟环形 */
pool->queue_size++;
/*添加完任务后，队列不为空，唤醒线程池中 等待处理任务的线程*/
pthread_cond_signal(&(pool->queue_not_empty));
pthread_mutex_unlock(&(pool->lock));
return 0;
}
/* 线程池中各个工作线程 */
void *threadpool_thread(void *threadpool)
{
threadpool_t *pool = (threadpool_t *)threadpool;
threadpool_task_t task;
while (true) {
/* Lock must be taken to wait on conditional variable */
/*刚创建出线程，等待任务队列里有任务，否则阻塞等待任务队列里有任务后再唤醒接收任务*/
pthread_mutex_lock(&(pool->lock));
/*queue_size == 0 说明没有任务，调 wait 阻塞在条件变量上, 若有任务，跳过该while*/
while ((pool->queue_size == 0) && (!pool->shutdown)) {
printf("thread 0x%x is waiting\n", (unsigned int)pthread_self());
pthread_cond_wait(&(pool->queue_not_empty), &(pool->lock));
/*清除指定数目的空闲线程，如果要结束的线程个数大于0，结束线程*/
if (pool->wait_exit_thr_num > 0) {
pool->wait_exit_thr_num--;
/*如果线程池里线程个数大于最小值时可以结束当前线程*/
if (pool->live_thr_num > pool->min_thr_num) {
printf("thread 0x%x is exiting\n", (unsigned int)pthread_self());
pool->live_thr_num--;
pthread_mutex_unlock(&(pool->lock));
pthread_exit(NULL);
}
}
}
/*如果指定了true，要关闭线程池里的每个线程，自行退出处理*/
if (pool->shutdown) {
pthread_mutex_unlock(&(pool->lock));
printf("thread 0x%x is exiting\n", (unsigned int)pthread_self());
pthread_exit(NULL); /* 线程自行结束 */
}
/*从任务队列里获取任务, 是一个出队操作*/
task.function = pool->task_queue[pool->queue_front].function;
task.arg = pool->task_queue[pool->queue_front].arg;
pool->queue_front = (pool->queue_front + 1) % pool->queue_max_size; /* 出队，模拟环形队列 */
pool->queue_size--;
/*通知可以有新的任务添加进来*/
pthread_cond_broadcast(&(pool->queue_not_full));
/*任务取出后，立即将 线程池琐 释放*/
pthread_mutex_unlock(&(pool->lock));
/*执行任务*/
printf("thread 0x%x start working\n", (unsigned int)pthread_self());
pthread_mutex_lock(&(pool->thread_counter)); /*忙状态线程数变量琐*/
pool->busy_thr_num++; /*忙状态线程数+1*/
pthread_mutex_unlock(&(pool->thread_counter));
(*(task.function))(task.arg); /*执行回调函数任务*/
//task.function(task.arg); /*执行回调函数任务*/
/*任务结束处理*/
printf("thread 0x%x end working\n", (unsigned int)pthread_self());
pthread_mutex_lock(&(pool->thread_counter));
pool->busy_thr_num--; /*处理掉一个任务，忙状态数线程数-1*/
pthread_mutex_unlock(&(pool->thread_counter));
}
pthread_exit(NULL);
}
/* 管理线程 */
void *adjust_thread(void *threadpool)
{
int i;
threadpool_t *pool = (threadpool_t *)threadpool;
while (!pool->shutdown) {
sleep(DEFAULT_TIME); /*定时 对线程池管理*/
pthread_mutex_lock(&(pool->lock));
int queue_size = pool->queue_size; /* 关注 任务数 */
int live_thr_num = pool->live_thr_num; /* 存活 线程数 */
pthread_mutex_unlock(&(pool->lock));
pthread_mutex_lock(&(pool->thread_counter));
int busy_thr_num = pool->busy_thr_num; /* 忙着的线程数 */
pthread_mutex_unlock(&(pool->thread_counter));
/* 创建新线程 算法： 任务数大于最小线程池个数, 且存活的线程数少于最大线程个数时 如：30>=10 && 40<100*/
if (queue_size >= MIN_WAIT_TASK_NUM && live_thr_num < pool->max_thr_num) {
pthread_mutex_lock(&(pool->lock));
int add = 0;
/*一次增加 DEFAULT_THREAD 个线程*/
for (i = 0; i < pool->max_thr_num && add < DEFAULT_THREAD_VARY
&& pool->live_thr_num < pool->max_thr_num; i++) {
if (pool->threads[i] == 0 || !is_thread_alive(pool->threads[i])) {
pthread_create(&(pool->threads[i]), NULL, threadpool_thread, (void *)pool);
add++;
pool->live_thr_num++;
}
}
pthread_mutex_unlock(&(pool->lock));
}
/* 销毁多余的空闲线程 算法：忙线程X2 小于 存活的线程数 且 存活的线程数 大于 最小线程数时*/
if ((busy_thr_num * 2) < live_thr_num && live_thr_num > pool->min_thr_num) {
/* 一次销毁DEFAULT_THREAD个线程, 隨機10個即可 */
pthread_mutex_lock(&(pool->lock));
pool->wait_exit_thr_num = DEFAULT_THREAD_VARY; /* 要销毁的线程数 设置为10 */
pthread_mutex_unlock(&(pool->lock));
for (i = 0; i < DEFAULT_THREAD_VARY; i++) {
/* 通知处在空闲状态的线程, 他们会自行终止*/
pthread_cond_signal(&(pool->queue_not_empty));
}
}
}
return NULL;
}
int threadpool_destroy(threadpool_t *pool)
{
int i;
if (pool == NULL) {
return -1;
}
pool->shutdown = true;
/*先销毁管理线程*/
pthread_join(pool->adjust_tid, NULL);
for (i = 0; i < pool->live_thr_num; i++) {
/*通知所有的空闲线程*/
pthread_cond_broadcast(&(pool->queue_not_empty));
}
for (i = 0; i < pool->live_thr_num; i++) {
pthread_join(pool->threads[i], NULL);
}
threadpool_free(pool);
return 0;
}
int threadpool_free(threadpool_t *pool)
{
if (pool == NULL) {
return -1;
}
if (pool->task_queue) {
free(pool->task_queue);
}
if (pool->threads) {
free(pool->threads);
pthread_mutex_lock(&(pool->lock));
pthread_mutex_destroy(&(pool->lock));
pthread_mutex_lock(&(pool->thread_counter));
pthread_mutex_destroy(&(pool->thread_counter));
pthread_cond_destroy(&(pool->queue_not_empty));
pthread_cond_destroy(&(pool->queue_not_full));
}
free(pool);
pool = NULL;
return 0;
}
int threadpool_all_threadnum(threadpool_t *pool)
{
int all_threadnum = -1;
pthread_mutex_lock(&(pool->lock));
all_threadnum = pool->live_thr_num;
pthread_mutex_unlock(&(pool->lock));
return all_threadnum;
}
int threadpool_busy_threadnum(threadpool_t *pool)
{
int busy_threadnum = -1;
pthread_mutex_lock(&(pool->thread_counter));
busy_threadnum = pool->busy_thr_num;
pthread_mutex_unlock(&(pool->thread_counter));
return busy_threadnum;
}
int is_thread_alive(pthread_t tid)
{
int kill_rc = pthread_kill(tid, 0); //发0号信号，测试线程是否存活
if (kill_rc == ESRCH) {
return false;
}
return true;
}
/*测试*/
#if 1
/* 线程池中的线程，模拟处理业务 */
void *process(void *arg)
{
printf("thread 0x%x working on task %d\n ",(unsigned int)pthread_self(),*(int *)arg);
sleep(1);
printf("task %d is end\n",*(int *)arg);
return NULL;
}
int main(void)
{
/*threadpool_t *threadpool_create(int min_thr_num, int max_thr_num, int queue_max_size);*/
threadpool_t *thp = threadpool_create(3,100,100);/*创建线程池，池里最小3个线程，最大100，队列最大100*/
printf("pool inited");
//int *num = (int *)malloc(sizeof(int)*20);
int num[20], i;
for (i = 0; i < 20; i++) {
num[i]=i;
printf("add task %d\n",i);
threadpool_add(thp, process, (void*)&num[i]); /* 向线程池中添加任务 */
}
sleep(10); /* 等子线程完成任务 */
threadpool_destroy(thp);
return 0;
}
#endif
/***
makefile
***/
src = $(wildcard *.c)
targets = $(patsubst %.c, %, $(src))
CC = gcc
CFLAGS = -lpthread -Wall -g
all:$(targets)
$(targets):%:%.c
$(CC) $< -o $@ $(CFLAGS)
.PHONY:clean all
clean:
-rm -rf $(targets)
运行结果：
ubuntu1604@ubuntu:~/wangqinghe/linux/20190831/01$ ./threadpool
start thread 0x8285700...
start thread 0x7a84700...
start thread 0x7283700...
pool initedadd task 0
add task 1
add task 2
add task 3
add task 4
add task 5
add task 6
add task 7
add task 8
add task 9
add task 10
add task 11
add task 12
add task 13
add task 14
add task 15
add task 16
add task 17
add task 18
add task 19
thread 0x7283700 start working
thread 0x7283700 working on task 0
thread 0x7a84700 start working
thread 0x7a84700 working on task 1
thread 0x8285700 start working
thread 0x8285700 working on task 2
task 0 is end
thread 0x7283700 end working
thread 0x7283700 start working
thread 0x7283700 working on task 3
task 1 is end
thread 0x7a84700 end working
thread 0x7a84700 start working
thread 0x7a84700 working on task 4
task 2 is end
thread 0x8285700 end working
thread 0x8285700 start working
thread 0x8285700 working on task 5
task 4 is end
thread 0x7a84700 end working
thread 0x7a84700 start working
thread 0x7a84700 working on task 6
task 3 is end
thread 0x7283700 end working
thread 0x7283700 start working
thread 0x7283700 working on task 7
task 5 is end
thread 0x8285700 end working
thread 0x8285700 start working
thread 0x8285700 working on task 8
^C
来源：https://www.cnblogs.com/wanghao-boke/p/11443241.html