c++实现的线程池

最新推荐文章于 2022-08-14 20:00:55 发布

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本文介绍了一个基于Ubuntu Linux的线程池实现，通过使用互斥锁、信号量等技术，有效地管理并发任务，包括任务列表的增删查改操作及线程的创建与销毁。实现了线程间任务的高效分配与执行。

下面这个线程池是我在工作中用到过的，原理还是建立一个任务队列，让多个线程互斥的在队列中取出任务，然后执行，显然，队列是要加锁的

环境：ubuntu linux

文件名：locker.h

#ifndef LOCKER_H_
#define LOCKER_H_

#include "pthread.h"


class locker
{
public:
	locker();
	virtual ~locker();

	bool lock();
	void unlock();

private:
    pthread_mutex_t     m_mutex;
};

#endif /* LOCKER_H_ */

文件名：locker.cpp

#include "locker.h"

locker::locker()
{
    pthread_mutex_init(&m_mutex, 0);
}

locker::~locker()
{
    pthread_mutex_destroy(&m_mutex);
}

bool locker::lock()
{
    if(0 == pthread_mutex_lock(&m_mutex))
        return true;
    return false;
}

void locker::unlock()
{
    pthread_mutex_unlock(&m_mutex);
}

文件名：task_list.h

#ifndef TASK_LIST_H_
#define TASK_LIST_H_

#include "list"
#include "locker.h"
#include "netinet/in.h"
#include "semaphore.h"

using namespace std;

typedef void* (*THREAD_FUNC)(void*);

// 线程池中运行的任务，对于下行任务，sin中包含目的地址信息
// parm0指向发出数据的对象，parm1指向数据，parm2为数据的长度
typedef struct
{
	THREAD_FUNC func;
	void* parm0;
	void* parm1;
	void* parm2;
} task_info;

typedef list<task_info*> TASK_LIST;
typedef list<task_info*>::iterator PTASK_LIST;

class task_list
{
public:
	task_list();
	virtual ~task_list();

	void append_task(task_info* tsk);
	task_info* fetch_task();

private:
	TASK_LIST m_tasklist;
	locker m_lk;
	sem_t m_sem;
};

#endif /* TASK_LIST_H_ */

文件名：task_list.cpp

#include "task_list.h"


task_list::task_list()
{
    // Init Semaphore
    sem_init(&m_sem, 0, 0);
    m_tasklist.clear();
}

task_list::~task_list()
{
    while(!m_tasklist.empty())
    {
        task_info* tr = m_tasklist.front();
        m_tasklist.pop_front();

        if(tr)
            delete tr;
    }
    // Destroy Semaphore
    sem_destroy(&m_sem);
}

void task_list::append_task(task_info* tsk)
{
    // Lock before Modify the list
    m_lk.lock();
    m_tasklist.push_back(tsk);
    m_lk.unlock();
    // Increase the Semaphore
    sem_post(&m_sem);
}

task_info* task_list::fetch_task()
{
    task_info* tr = NULL;

    sem_wait(&m_sem);

    m_lk.lock();
    tr = m_tasklist.front();
    m_tasklist.pop_front();
    m_lk.unlock();

    return tr;
}

文件名：thread_pool.h

#ifndef THREAD_POOL_H_
#define THREAD_POOL_H_

#include "task_list.h"
#include "pthread.h"

#define DEFAULT_THREAD_COUNT    4
#define MAXIMUM_THREAD_COUNT    1000


class thread_pool
{
public:
	thread_pool();
	virtual ~thread_pool();

	int  create_threads(int n = DEFAULT_THREAD_COUNT);
	void delete_threads();

	void set_tasklist(task_list* plist);
	void del_tasklist();

protected:
    static void* thread_func(void* parm);
    task_info* get_task();

private:
    int             m_thread_cnt;
    pthread_t       m_pids[MAXIMUM_THREAD_COUNT];

    task_list*      m_tasklist;
};

#endif /* THREAD_POOL_H_ */

文件名:thread_pool.cpp

#include "thread_pool.h"

thread_pool::thread_pool()
{
	m_thread_cnt = 0;
	m_tasklist = NULL;
}

thread_pool::~thread_pool()
{
	delete_threads();
}

task_info* thread_pool::get_task()
{
	task_info* tr;

	if (m_tasklist)
	{
		tr = m_tasklist->fetch_task();
		return tr;
	}

	return NULL;
}

void* thread_pool::thread_func(void* parm)
{
	thread_pool *ptp = static_cast<thread_pool*> (parm);
	task_info *task;

	while (true)
	{
		task = ptp->get_task();
		if (task)
		{
			(*task->func)(task);
			//delete task; //func负责释放task_info
		}
	}
	return NULL;
}

int thread_pool::create_threads(int n)
{
	if (n > MAXIMUM_THREAD_COUNT)
		n = MAXIMUM_THREAD_COUNT;

	delete_threads();

	for (int i = 0; i < n; i++)
	{
		int ret = pthread_create(&m_pids[i], NULL, thread_func, (void*) this);
		if (ret != 0)
			break;
		m_thread_cnt++;
	}

	return m_thread_cnt;
}

void thread_pool::delete_threads()
{
	for (int i = 0; i < m_thread_cnt; i++)
	{
		void* retval;

		pthread_cancel(m_pids[i]);
		pthread_join(m_pids[i], &retval);
	}
	m_thread_cnt = 0;
}

void thread_pool::set_tasklist(task_list* plist)
{
	m_tasklist = plist;
}

void thread_pool::del_tasklist()
{
	m_tasklist = NULL;
}

文件名：test.cpp

#include "unistd.h"
#include "stdio.h"
#include "stdlib.h"
#include "task_list.h"
#include "thread_pool.h"


void* fun(void *parm)
{
	task_info* ptk = (task_info*)parm;
	pid_t tid = pthread_self();
	int count = (int)ptk->parm0;
	printf("count=%d, tid=%d\n", count, tid);
	return NULL;
}

int main()
{
	int count = 0;
	thread_pool tp;
	task_list tl;

	tp.create_threads(4 - 1);
	tp.set_tasklist(&tl);

	while (1)
	{
		task_info* pti = NULL;
		pti = (task_info *) malloc(sizeof(task_info));
		pti->func = fun;
		pti->parm0 = (void *)count;
		tl.append_task(pti);
		count++;
		sleep(2);
	}
//	printf("hello,world\n");
	return 0;
}

编译运行，我是用ecplise建立的automake工程，所以只要修改一下Makefile.am就可以编译成功了

文件名:Makefile.am

bin_PROGRAMS=test
test_SOURCES=test.cpp locker.h locker.cpp \
 							task_list.h task_list.cpp \
 							thread_pool.h thread_pool.cpp
test_LDADD=-lpthread

执行结果：

count=0, tid=-1219888272
count=1, tid=-1219888272
count=2, tid=-1228280976
count=3, tid=-1236673680
count=4, tid=-1219888272
count=5, tid=-1228280976
count=6, tid=-1236673680
count=7, tid=-1219888272
count=8, tid=-1228280976
count=9, tid=-1236673680

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