通过本文主要向大家介绍了c语言线程池,c语言实现线程池,c语言线程,c语言多线程编,c语言创建线程等相关知识,希望对您有所帮助,也希望大家支持linkedu.com www.linkedu.com
本文实例介绍了C 语言实现线程池，支持动态拓展和销毁，分享给大家供大家参考，具体内容如下
实现功能
- 1.初始化指定个数的线程
- 2.使用链表来管理任务队列
- 3.支持拓展动态线程
- 4.如果闲置线程过多,动态销毁部分线程
#include <stdio.h>
#include <pthread.h>
#include <stdlib.h>
#include <signal.h>
/*线程的任务队列由,函数和参数组成,任务由链表来进行管理*/
typedef struct thread_worker_s{
void *(*process)(void *arg); //处理函数
void *arg; //参数
struct thread_worker_s *next;
}thread_worker_t;
#define bool int
#define true 1
#define false 0
/*线程池中各线程状态描述*/
#define THREAD_STATE_RUN 0
#define THREAD_STATE_TASK_WAITING 1
#define THREAD_STATE_TASK_PROCESSING 2
#define THREAD_STATE_TASK_FINISHED 3
#define THREAD_STATE_EXIT 4
typedef struct thread_info_s{
pthread_t id;
int state;
struct thread_info_s *next;
}thread_info_t;
static char* thread_state_map[] ={"创建","等待任务","处理中","处理完成","已退出"};
/*线程压缩的时候只有 0,1,2,4 状态的线程可以销毁*/
/*线程池管理器*/
#define THREAD_BUSY_PERCENT 0.5 /*线程:任务 = 1:2 值越小，说明任务多,增加线程*/
#define THREAD_IDLE_PERCENT 2 /*线程:任务 = 2:1 值大于1,线程多于任务,销毁部分线程*/
typedef struct thread_pool_s{
pthread_mutex_t queue_lock ; //队列互斥锁,即涉及到队列修改时需要加锁
pthread_cond_t queue_ready; //队列条件锁,队列满足某个条件，触发等待这个条件的线程继续执行,比如说队列满了,队列空了
thread_worker_t *head ; //任务队列头指针
bool is_destroy ; //线程池是否已经销毁
int num; //线程的个数
int rnum; ; //正在跑的线程
int knum; ; //已杀死的线程
int queue_size ; //工作队列的大小
thread_info_t *threads ; //线程组id,通过pthread_join(thread_ids[0],NULL) 来执行线程
pthread_t display ; //打印线程
pthread_t destroy ; //定期销毁线程的线程id
pthread_t extend ;
float percent ; //线程个数于任务的比例 rnum/queue_size
int init_num ;
pthread_cond_t extend_ready ; //如果要增加线程
}thread_pool_t;
/*-------------------------函数声明----------------------*/
/**
* 1.初始化互斥变量
* 2.初始化等待变量
* 3.创建指定个数的线程线程
*/
thread_pool_t* thread_pool_create(int num);
void *thread_excute_route(void *arg);
/*调试函数*/
void debug(char *message,int flag){
if(flag)
printf("%s\n",message);
}
void *display_thread(void *arg);
/**
* 添加任务包括以下几个操作
* 1.将任务添加到队列末尾
* 2.通知等待进程来处理这个任务 pthread_cond_singal();
*/
int thread_pool_add_worker(thread_pool_t *pool,void*(*process)(void *arg),void *arg); //网线程池的队列中增加一个需要执行的函数，也就是任务
/**
* 销毁线程池,包括以下几个部分
* 1.通知所有等待的进程 pthread_cond_broadcase
* 2.等待所有的线程执行完
* 3.销毁任务列表
* 4.释放锁，释放条件
* 4.销毁线程池对象
*/
void *thread_pool_is_need_recovery(void *arg);
void *thread_pool_is_need_extend(void *arg);
void thread_pool_destory(thread_pool_t *pool);
thread_pool_t *thread_pool_create(int num){
if(num<1){
return NULL;
}
thread_pool_t *p;
p = (thread_pool_t*)malloc(sizeof(struct thread_pool_s));
if(p==NULL)
return NULL;
p->init_num = num;
/*初始化互斥变量与条件变量*/
pthread_mutex_init(&(p->queue_lock),NULL);
pthread_cond_init(&(p->queue_ready),NULL);
/*设置线程个数*/
p->num = num;
p->rnum = num;
p->knum = 0;
p->head = NULL;
p->queue_size =0;
p->is_destroy = false;
int i=0;
thread_info_t *tmp=NULL;
for(i=0;i<num;i++){
/*创建线程*/
tmp= (struct thread_info_s*)malloc(sizeof(struct thread_info_s));
if(tmp==NULL){
free(p);
return NULL;
}else{
tmp->next = p->threads;
p->threads = tmp;
}
pthread_create(&(tmp->id),NULL,thread_excute_route,p);
tmp->state = THREAD_STATE_RUN;
}
/*显示*/
pthread_create(&(p->display),NULL,display_thread,p);
/*检测是否需要动态线程*/
//pthread_create(&(p->extend),NULL,thread_pool_is_need_extend,p);
/*动态销毁*/
pthread_create(&(p->destroy),NULL,thread_pool_is_need_recovery,p);
return p;
}
int thread_pool_add_worker(thread_pool_t *pool,void*(*process)(void*arg),void*arg){
thread_pool_t *p= pool;
thread_worker_t *worker=NULL,*member=NULL;
worker = (thread_worker_t*)malloc(sizeof(struct thread_worker_s));
int incr=0;
if(worker==NULL){
return -1;
}
worker->process = process;
worker->arg = arg;
worker->next = NULL;
thread_pool_is_need_extend(pool);
pthread_mutex_lock(&(p->queue_lock));
member = p->head;
if(member!=NULL){
while(member->next!=NULL)
member = member->next;
member->next = worker;
}else{
p->head = worker;
}
p->queue_size ++;
pthread_mutex_unlock(&(p->queue_lock));
pthread_cond_signal(&(p->queue_ready));
return 1;
}
void thread_pool_wait(thread_pool_t *pool){
thread_info_t *thread;
int i=0;
for(i=0;i<pool->num;i++){
thread = (thread_info_t*)(pool->threads+i);
thread->state = THREAD_STATE_EXIT;
pthread_join(thread->id,NULL);
}
}
void thread_pool_destory(thread_pool_t *pool){
thread_pool_t *p = pool;
thread_worker_t *member = NULL;
if(p->is_destroy)
return ;
p->is_destroy = true;
pthread_cond_broadcast(&(p->queue_ready));
thread_pool_wait(pool);
free(p->threads);
p->threads = NULL;
/*销毁任务列表*/
while(p->head){
member = p->head;
p->head = member->next;
free(member);
}
/*销毁线程列表*/
thread_info_t *tmp=NULL;
while(p->threads){
tmp = p->threads;
p->threads = tmp->next;
free(tmp);
}
pthread_mutex_destroy(&(p->queue_lock));
pthread_cond_destroy(&(p->queue_ready));
return ;
}
/*通过线程id,找到对应的线程*/
thread_info_t *get_thread_by_id(thread_pool_t *pool,pthread_t id){
thread_info_t *thread=NULL;
thread_info_t *p=pool->threads;
while(p!=NULL){
if(p->id==id)
return p;
p = p->next;
}
return NULL;
}
/*每个线程入口函数*/
void *thread_excute_route(void *arg){
thread_worker_t *worker = NULL;
thread_info_t *thread = NULL;
thread_pool_t* p = (thread_pool_t*)arg;
//printf("thread %lld create success\n",pthread_self());
while(1){
pthread_mutex_lock(&(p->queue_lock));
/*获取当前线程的id*/
pthread_t pthread_id = pthread_self();
/*设置当前状态*/
thread = get_thread_by_id(p,pthread_id);
/*线程池被销毁,并且没有任务了*/
if(p->is_destroy==true && p->queue_size ==0){
pthread_mutex_unlock(&(p->queue_lock));
thread->state = THREAD_STATE_EXIT;
p->knum ++;
p->rnum --;
pthread_exit(NULL);
}
if(thread){
thread->state = THREAD_STATE_TASK_WAITING; /*线程正在等待任务*/
}
/*线程池没有被销毁,没有任务到来就一直等待*/
while(p->queue_size==0 && !p->is_destroy){
pthread_cond_wait(&(p->queue_ready),&(p->queue_lock));
}
p->queue_size--;
worker = p->head;
p->head = worker->next;
pthread_mutex_unlock(&(p->queue_lock));
if(thread)
thread->state = THREAD_STATE_TASK_PROCESSING; /*线程正在执行任务*/
(*(worker->process))(worker->arg);
if(thread)
thread->state = THREAD_STATE_TASK