Question

我最近一直在自己的线程池实现上工作，它运行正常（非常多）。问题是它几乎占用了所有CPU资源。请看一下我的实现：

ThreadPool.h

#include <vector>
#include <list>
#include <Windows.h>

const int DefaultThreadsNumber = 5;

class thread_pool
{
    typedef void ( *Task )( );

    void* m_hEvent;

    CRITICAL_SECTION m_hExecuteFunc;
    CRITICAL_SECTION m_hRunFunc;


    std::vector<void*> m_ThreadHandles;
    std::list<Task> m_TasksQueue;
    int m_nThreadInQueue;
    static unsigned __stdcall Run( void* thisParam );
public:
    thread_pool( int nMaxThreadNo );
    ~thread_pool();
    void Execute( Task task );
};

ThreadPool.cpp

#include "thread_pool.h"
#include <process.h>

void* g_hTaskFinishedEvent;

thread_pool::thread_pool( int nMaxThreadNo )
{
    if ( nMaxThreadNo <= 0 )
        nMaxThreadNo = DefaultThreadsNumber;

    m_nThreadInQueue = nMaxThreadNo;
    for( int i = 0; i < nMaxThreadNo; ++i )
    {
        m_ThreadHandles.push_back((void*)_beginthreadex(NULL, 0, &Run, (void*)this, 0, 0 ));
    }

    InitializeCriticalSection( &m_hExecuteFunc );
    InitializeCriticalSection( &m_hRunFunc );
}


thread_pool::~thread_pool()
{
    for ( std::vector<void*>::iterator it = m_ThreadHandles.begin(); 
            it != m_ThreadHandles.end(); 
            ++it )
    {
        CloseHandle( *it );
    }

    DeleteCriticalSection( &m_hExecuteFunc );
    DeleteCriticalSection( &m_hRunFunc );

}

void thread_pool::Execute( Task task )
{
    EnterCriticalSection( &m_hExecuteFunc );

    m_TasksQueue.push_back( task );

    LeaveCriticalSection( &m_hExecuteFunc );

    m_hEvent = CreateEvent(NULL, true, false, NULL);
    SetEvent( m_hEvent ); // TODO: what if setEvent will fail???
}

unsigned __stdcall thread_pool::Run(void* thisParam )
{
    thread_pool *This = (thread_pool*)thisParam;
    while(true)
    {
        WaitForSingleObject( This->m_hEvent, INFINITE );
        while(!This->m_TasksQueue.empty())
        {


            EnterCriticalSection( &This->m_hExecuteFunc );

            if ( !This->m_TasksQueue.empty() ) 
            {
                This->m_TasksQueue.front()();
                This->m_TasksQueue.pop_front();

                g_hTaskFinishedEvent = CreateEvent(NULL, true, false, NULL);
                SetEvent( g_hTaskFinishedEvent );
            }

            LeaveCriticalSection( &This->m_hExecuteFunc );
        }
    }
    return 0;
}

如何改进？

先谢谢。

Answer 1

在CreateEvent中，bManualReset设置为true，但您不是在任何地方调用ResetEvent。因此，一旦发出信号，该事件将永远保持设置，并且WaitForSingleObject立即返回。将其设为自动重置事件，或在完成所有工作后调用ResetEvent。

线程池正在占用所有CPU资源

1 个答案: