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一个Windows C++的线程池的实现

2010-08-13 15:30 477 查看
此线程池所依赖的线程类,请参看《一个Windows C++的线程类实现》:
http://blog.csdn.net/huyiyang2010/archive/2010/08/10/5801597.aspx
ThreadPoolExecutor.h

#ifndef __THREAD_POOL_EXECUTOR__
#define __THREAD_POOL_EXECUTOR__

#include "Thread.h"
#include <set>
#include <list>
#include <windows.h>

class CThreadPoolExecutor
{
public:
CThreadPoolExecutor(void);
~CThreadPoolExecutor(void);

/**
初始化线程池,创建minThreads个线程
**/
bool Init(unsigned int minThreads, unsigned int maxThreads, unsigned int maxPendingTaskse);

/**
执行任务,若当前任务列表没有满,将此任务插入到任务列表,返回true
若当前任务列表满了,但当前线程数量小于最大线程数,将创建新线程执行此任务,返回true
若当前任务列表满了,但当前线程数量等于最大线程数,将丢弃此任务,返回false
**/
bool Execute(Runnable * pRunnable);

/**
终止线程池,先制止塞入任务,
然后等待直到任务列表为空,
然后设置最小线程数量为0,
等待直到线程数量为空,
清空垃圾堆中的任务
**/
void Terminate();

/**
返回线程池中当前的线程数量
**/
unsigned int GetThreadPoolSize();

private:
/**
获取任务列表中的任务,若任务列表为空,返回NULL
**/
Runnable * GetTask();

static unsigned int WINAPI StaticThreadFunc(void * arg);

private:
class CWorker : public CThread
{
public:
CWorker(CThreadPoolExecutor * pThreadPool, Runnable * pFirstTask = NULL);
~CWorker();
void Run();

private:
CThreadPoolExecutor * m_pThreadPool;
Runnable * m_pFirstTask;
volatile bool m_bRun;
};

typedef std::set<CWorker *> ThreadPool;
typedef std::list<Runnable *> Tasks;
typedef Tasks::iterator TasksItr;
typedef ThreadPool::iterator ThreadPoolItr;

ThreadPool m_ThreadPool;
ThreadPool m_TrashThread;
Tasks m_Tasks;

CRITICAL_SECTION m_csTasksLock;
CRITICAL_SECTION m_csThreadPoolLock;

volatile bool m_bRun;
volatile bool m_bEnableInsertTask;
volatile unsigned int m_minThreads;
volatile unsigned int m_maxThreads;
volatile unsigned int m_maxPendingTasks;
};

#endif


ThreadPoolExecutor.cpp

#include "ThreadPoolExecutor.h"

CThreadPoolExecutor::CWorker::CWorker(CThreadPoolExecutor * pThreadPool, Runnable * pFirstTask) :
m_pThreadPool(pThreadPool),
m_pFirstTask(pFirstTask),
m_bRun(true)
{

}

CThreadPoolExecutor::CWorker::~CWorker()
{
}

/**
执行任务的工作线程。
当前没有任务时,
如果当前线程数量大于最小线程数量,减少线程,
否则,执行清理程序,将线程类给释放掉
**/
void CThreadPoolExecutor::CWorker::Run()
{
Runnable * pTask = NULL;
while(m_bRun)
{
if(NULL == m_pFirstTask)
{
pTask = m_pThreadPool->GetTask();
}
else
{
pTask = m_pFirstTask;
m_pFirstTask = NULL;
}

if(NULL == pTask)
{
EnterCriticalSection(&(m_pThreadPool->m_csThreadPoolLock));
if(m_pThreadPool->GetThreadPoolSize() > m_pThreadPool->m_minThreads)
{
ThreadPoolItr itr = m_pThreadPool->m_ThreadPool.find(this);
if(itr != m_pThreadPool->m_ThreadPool.end())
{
m_pThreadPool->m_ThreadPool.erase(itr);
m_pThreadPool->m_TrashThread.insert(this);
}
m_bRun = false;
}
else
{
ThreadPoolItr itr = m_pThreadPool->m_TrashThread.begin();
while(itr != m_pThreadPool->m_TrashThread.end())
{
(*itr)->Join();
delete (*itr);
m_pThreadPool->m_TrashThread.erase(itr);
itr = m_pThreadPool->m_TrashThread.begin();
}
}
LeaveCriticalSection(&(m_pThreadPool->m_csThreadPoolLock));
continue;
}
else
{
pTask->Run();
pTask = NULL;
}
}
}

/////////////////////////////////////////////////////////////////////////////////////////////

CThreadPoolExecutor::CThreadPoolExecutor(void) :
m_bRun(false),
m_bEnableInsertTask(false)
{
InitializeCriticalSection(&m_csTasksLock);
InitializeCriticalSection(&m_csThreadPoolLock);
}

CThreadPoolExecutor::~CThreadPoolExecutor(void)
{
Terminate();
DeleteCriticalSection(&m_csTasksLock);
DeleteCriticalSection(&m_csThreadPoolLock);
}

bool CThreadPoolExecutor::Init(unsigned int minThreads, unsigned int maxThreads, unsigned int maxPendingTasks)
{
if(minThreads == 0)
{
return false;
}
if(maxThreads < minThreads)
{
return false;
}
m_minThreads = minThreads;
m_maxThreads = maxThreads;
m_maxPendingTasks = maxPendingTasks;
unsigned int i = m_ThreadPool.size();
for(; i<minThreads; i++)
{
//创建线程
CWorker * pWorker = new CWorker(this);
if(NULL == pWorker)
{
return false;
}
EnterCriticalSection(&m_csThreadPoolLock);
m_ThreadPool.insert(pWorker);
LeaveCriticalSection(&m_csThreadPoolLock);
pWorker->Start();
}
m_bRun = true;
m_bEnableInsertTask = true;
return true;
}

bool CThreadPoolExecutor::Execute(Runnable * pRunnable)
{
if(!m_bEnableInsertTask)
{
return false;
}
if(NULL == pRunnable)
{
return false;
}
if(m_Tasks.size() >= m_maxPendingTasks)
{
if(m_ThreadPool.size() < m_maxThreads)
{
CWorker * pWorker = new CWorker(this, pRunnable);
if(NULL == pWorker)
{
return false;
}
EnterCriticalSection(&m_csThreadPoolLock);
m_ThreadPool.insert(pWorker);
LeaveCriticalSection(&m_csThreadPoolLock);
pWorker->Start();
}
else
{
return false;
}
}
else
{
EnterCriticalSection(&m_csTasksLock);
m_Tasks.push_back(pRunnable);
LeaveCriticalSection(&m_csTasksLock);
}
return true;
}

Runnable * CThreadPoolExecutor::GetTask()
{
Runnable * Task = NULL;
EnterCriticalSection(&m_csTasksLock);
if(!m_Tasks.empty())
{
Task = m_Tasks.front();
m_Tasks.pop_front();
}
LeaveCriticalSection(&m_csTasksLock);
return Task;
}

unsigned int CThreadPoolExecutor::GetThreadPoolSize()
{
return m_ThreadPool.size();
}

void CThreadPoolExecutor::Terminate()
{
m_bEnableInsertTask = false;
while(m_Tasks.size() > 0)
{
Sleep(1);
}
m_bRun = false;
m_minThreads = 0;
m_maxThreads = 0;
m_maxPendingTasks = 0;
while(m_ThreadPool.size() > 0)
{
Sleep(1);
}
EnterCriticalSection(&m_csThreadPoolLock);
ThreadPoolItr itr = m_TrashThread.begin();
while(itr != m_TrashThread.end())
{
(*itr)->Join();
delete (*itr);
m_TrashThread.erase(itr);
itr = m_TrashThread.begin();
}
LeaveCriticalSection(&m_csThreadPoolLock);
}


用法:

#include "Thread.h"
#include "ThreadPoolExecutor.h"

class R : public Runnable
{
public:
~R()
{
}
void Run()
{
printf("Hello World/n");
}
};

int _tmain(int argc, _TCHAR* argv[])
{
CThreadPoolExecutor * pExecutor = new CThreadPoolExecutor();
pExecutor->Init(1, 10, 50);
R r;
for(int i=0;i<100;i++)
{
while(!pExecutor->Execute(&r))
{
}
}
pExecutor->Terminate();
delete pExecutor;
getchar();
return 0;
}

测试结果:

机器:

Intel(R) Core(TM)2 Duo CPU

E8400 @ 3.00GHz

2G内存

对于100个任务并且每个任务包含10000000个循环,任务中无等待:

单线程执行耗时:2281时间片

单线程池执行耗时:2219时间片

2个线程的线程池耗时:1156时间片

5个线程的线程池耗时:1166时间片

10个线程的线程池耗时:1157时间片

100个线程的线程池耗时:1177时间片
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