[C#]I/O完成端口的类定义和测试实例

整理者:郑昀@UltraPower
日期:2005-04-13

从William Kennedy那里整理过来的,不同之处在于他自己定义了一个Overlapped,而我们这里直接使用
System.Threading.NativeOverlapped:。

附一段我以前的Win32下的IOCP文档,如果您了解IOCP也可以直接跳过看后面的C#测试示范:

我们采用的是I/O Complete Port(以下简称IOCP)处理机制。

简单的讲,当服务应用程序初始化时,它应该先创建一个I/O CP。我们在请求到来后,将得到的数据打包用PostQueuedCompletionStatus发送到IOCP中。这时需要创建一些个线程(7个线程/CPU,再多就没有意义了)来处理发送到IOCP端口的消息。实现步骤大致如下:

1     先在主线程中调用CreateIoCompletionPort创建IOCP

CreateIoCompletionPort的前三个参数只在把设备同Complete Port相关联时才有用。

此时我们只需传递INVALID_HANDLE_VALUE,NULL0即可。

第四个参数告诉端口同时能运行的最多线程数,这里设置为0,表示默认为当前计算机的CPU数目。

2     我们的ThreadFun线程函数执行一些初始化之后,将进入一个循环,该循环会在服务进程终止时才结束。

在循环中,调用GetQueuedCompletionStatus,这样就把当前线程的ID放入一个等待线程队列中,I/O CP内核对象就总能知道哪个线程在等待处理完成的I/O请求。

如果在IDLE_THREAD_TIMEOUT规定的时间内I/O CP上还没有出现一个Completion Packet,则转入下一次循环。在这里我们设置的IDLE_THREAD_TIMEOUT1秒。

 

当端口的I/O完成队列中出现一项时,完成端口就唤醒等待线程队列中的这个线程,该线程将得到完成的I/O项中的信息:       传输的字节数、完成键和OVERLAPPED结构的地址。

 

在我们的程序中可以用智能指针或者BSTR或者int来接受这个OVERLAPPED结构的地址的值,从而得到消息;然后在这个线程中处理消息。

GetQueuedCompletionStatus的第一个参数hCompletionPort指出了要监视哪一个端口,这里我们传送先前从CreateIoCompletionPort返回的端口句柄。

 

需要注意的是:

第一,   线程池的数目是有限制的,和CPU数目有关系。

第二,   IOCP是一种较为完美的睡眠/唤醒 线程机制;线程当前没有任务要处理时,就进入睡眠状态,从而不占用CPU资源,直到被内核唤醒;

第三,   最近一次刚执行完的线程,下次任务来的时候还会唤醒它;所以有可能比较少被调用的线程以后被调用的几率也少。

 


测试代码:

using System;
using System.Threading;  // Included for the Thread.Sleep call
using Continuum.Threading;
using System.Runtime.InteropServices;

namespace IOCPDemo
{
    
//=============================================================================
    /// <summary> Sample class for the threading class </summary>
    public class UtilThreadingSample
    
{
        
//*****************************************************************************   
        /// <summary> Test Method </summary>
        static void Main()
        
{
            
// Create the MSSQL IOCP Thread Pool
            IOCPThreadPool pThreadPool = new IOCPThreadPool(01020new IOCPThreadPool.USER_FUNCTION(IOCPThreadFunction));
      
            
//for(int i =1;i<10000;i++)
            {
                pThreadPool.PostEvent(
1234);
            }

      
            Thread.Sleep(
100);
      
            pThreadPool.Dispose();
        }

    
        
//********************************************************************
        /// <summary> Function to be called by the IOCP thread pool.  Called when
        
///           a command is posted for processing by the SocketManager </summary>
        
/// <param name="iValue"> The value provided by the thread posting the event </param>

        static public void IOCPThreadFunction(int iValue)
        
{
            
try
            
{
                Console.WriteLine(
"Value: {0}", iValue.ToString());
                Thread.Sleep(
3000);
            }

      
            
catch (Exception pException)
            
{
                Console.WriteLine(pException.Message);
            }

        }

    }


}



类代码:
using System;
using System.Threading;
using System.Runtime.InteropServices;

namespace IOCPThreading
{
    [StructLayout(LayoutKind.Sequential, CharSet
=CharSet.Auto)]

    
public sealed class IOCPThreadPool
    
{
        [DllImport(
"Kernel32", CharSet=CharSet.Auto)]
        
private unsafe static extern UInt32 CreateIoCompletionPort(UInt32 hFile, UInt32 hExistingCompletionPort, UInt32* puiCompletionKey, UInt32 uiNumberOfConcurrentThreads);

        [DllImport(
"Kernel32", CharSet=CharSet.Auto)]
        
private unsafe static extern Boolean CloseHandle(UInt32 hObject);

        [DllImport(
"Kernel32", CharSet=CharSet.Auto)]
        
private unsafe static extern Boolean PostQueuedCompletionStatus(UInt32 hCompletionPort, UInt32 uiSizeOfArgument, UInt32* puiUserArg, System.Threading.NativeOverlapped* pOverlapped);

        [DllImport(
"Kernel32", CharSet=CharSet.Auto)]
        
private unsafe static extern Boolean GetQueuedCompletionStatus(UInt32 hCompletionPort, UInt32* pSizeOfArgument, UInt32* puiUserArg, System.Threading.NativeOverlapped** ppOverlapped, UInt32 uiMilliseconds);

        
private const UInt32 INVALID_HANDLE_VALUE = 0xffffffff;
        
private const UInt32 INIFINITE = 0xffffffff;
        
private const Int32 SHUTDOWN_IOCPTHREAD = 0x7fffffff;
        
public delegate void USER_FUNCTION(int iValue);
        
private UInt32 m_hHandle;
        
private UInt32 GetHandle get return m_hHandle; } set { m_hHandle = value; } }

        
private Int32 m_uiMaxConcurrency;

        
private Int32 GetMaxConcurrency get return m_uiMaxConcurrency; } set { m_uiMaxConcurrency = value; } }


        
private Int32 m_iMinThreadsInPool;

        
private Int32 GetMinThreadsInPool get return m_iMinThreadsInPool; } set { m_iMinThreadsInPool = value; } }

        
private Int32 m_iMaxThreadsInPool;

        
private Int32 GetMaxThreadsInPool get return m_iMaxThreadsInPool; } set { m_iMaxThreadsInPool = value; } }


        
private Object m_pCriticalSection;

        
private Object GetCriticalSection get return m_pCriticalSection; } set { m_pCriticalSection = value; } }


        
private USER_FUNCTION m_pfnUserFunction;

        
private USER_FUNCTION GetUserFunction get return m_pfnUserFunction; } set { m_pfnUserFunction = value; } }


        
private Boolean m_bDisposeFlag;

        
/// <summary> SimType: Flag to indicate if the class is disposing </summary>

        
private Boolean IsDisposed get return m_bDisposeFlag; } set { m_bDisposeFlag = value; } }

        
private Int32 m_iCurThreadsInPool;

        
/// <summary> SimType: The current number of threads in the thread pool </summary>

        
public Int32 GetCurThreadsInPool get return m_iCurThreadsInPool; } set { m_iCurThreadsInPool = value; } }

        
/// <summary> SimType: Increment current number of threads in the thread pool </summary>

        
private Int32 IncCurThreadsInPool() return Interlocked.Increment(ref m_iCurThreadsInPool); }

        
/// <summary> SimType: Decrement current number of threads in the thread pool </summary>

        
private Int32 DecCurThreadsInPool() return Interlocked.Decrement(ref m_iCurThreadsInPool); }


        
private Int32 m_iActThreadsInPool;

        
/// <summary> SimType: The current number of active threads in the thread pool </summary>

        
public Int32 GetActThreadsInPool get return m_iActThreadsInPool; } set { m_iActThreadsInPool = value; } }

        
/// <summary> SimType: Increment current number of active threads in the thread pool </summary>

        
private Int32 IncActThreadsInPool() return Interlocked.Increment(ref m_iActThreadsInPool); }

        
/// <summary> SimType: Decrement current number of active threads in the thread pool </summary>

        
private Int32 DecActThreadsInPool() return Interlocked.Decrement(ref m_iActThreadsInPool); }


        
private Int32 m_iCurWorkInPool;

        
/// <summary> SimType: The current number of Work posted in the thread pool </summary>

        
public Int32 GetCurWorkInPool get return m_iCurWorkInPool; } set { m_iCurWorkInPool = value; } }

        
/// <summary> SimType: Increment current number of Work posted in the thread pool </summary>

        
private Int32 IncCurWorkInPool() return Interlocked.Increment(ref m_iCurWorkInPool); }

        
/// <summary> SimType: Decrement current number of Work posted in the thread pool </summary>

        
private Int32 DecCurWorkInPool() return Interlocked.Decrement(ref m_iCurWorkInPool); }

        
public IOCPThreadPool(Int32 iMaxConcurrency, Int32 iMinThreadsInPool, Int32 iMaxThreadsInPool, USER_FUNCTION pfnUserFunction)
        
{
            
try
            
{
                
// Set initial class state

                GetMaxConcurrency   
= iMaxConcurrency;

                GetMinThreadsInPool 
= iMinThreadsInPool;

                GetMaxThreadsInPool 
= iMaxThreadsInPool;

                GetUserFunction     
= pfnUserFunction;


                
// Init the thread counters

                GetCurThreadsInPool 
= 0;

                GetActThreadsInPool 
= 0;

                GetCurWorkInPool    
= 0;


                
// Initialize the Monitor Object

                GetCriticalSection 
= new Object();


                
// Set the disposing flag to false

                IsDisposed 
= false;


                
unsafe
                
{

                    
// Create an IO Completion Port for Thread Pool use
                    GetHandle = CreateIoCompletionPort(INVALID_HANDLE_VALUE, 0null, (UInt32) GetMaxConcurrency);

                }



                
// Test to make sure the IO Completion Port was created

                
if (GetHandle == 0)

                    
throw new Exception("Unable To Create IO Completion Port");


                
// Allocate and start the Minimum number of threads specified

                Int32 iStartingCount 
= GetCurThreadsInPool;

        

                ThreadStart tsThread 
= new ThreadStart(IOCPFunction);

                
for (Int32 iThread = 0; iThread < GetMinThreadsInPool; ++iThread)
                
{

                    
// Create a thread and start it

                    Thread thThread 
= new Thread(tsThread);

                    thThread.Name 
= "IOCP " + thThread.GetHashCode();

                    thThread.Start();


                    
// Increment the thread pool count

                    IncCurThreadsInPool();

                }


            }



            
catch
            
{

                
throw new Exception("Unhandled Exception");

            }


        }


        
~IOCPThreadPool()
        
{

            
if (!IsDisposed)

                Dispose();

        }


        
public void Dispose()
        
{

            
try
            
{

                
// Flag that we are disposing this object

                IsDisposed 
= true;


                
// Get the current number of threads in the pool

                Int32 iCurThreadsInPool 
= GetCurThreadsInPool;


                
// Shutdown all thread in the pool

                
for (Int32 iThread = 0; iThread < iCurThreadsInPool; ++iThread)
                
{
                    
unsafe
                    
{

                        
bool bret = PostQueuedCompletionStatus(GetHandle, 4, (UInt32*) SHUTDOWN_IOCPTHREAD, null);

                    }


                }



                
// Wait here until all the threads are gone

                
while (GetCurThreadsInPool != 0) Thread.Sleep(100);


                
unsafe
                
{

                    
// Close the IOCP Handle
                    CloseHandle(GetHandle);

                }


            }


            
catch
            
{

            }


        }

        
private void IOCPFunction()
        
{
            UInt32 uiNumberOfBytes;

            Int32  iValue;

            
try
            
{
                
while (true)
                
{

                    
unsafe
                    
{

                        System.Threading.NativeOverlapped
* pOv;


                        
// Wait for an event

                        GetQueuedCompletionStatus(GetHandle, 
&uiNumberOfBytes, (UInt32*&iValue, &pOv, INIFINITE);
                    }


                    
// Decrement the number of events in queue

                    DecCurWorkInPool();


                    
// Was this thread told to shutdown

                    
if (iValue == SHUTDOWN_IOCPTHREAD)

                        
break;


                    
// Increment the number of active threads

                    IncActThreadsInPool();


                    
try
                    
{
                        
// Call the user function
                        GetUserFunction(iValue);

                    }


                    
catch(Exception ex)
                    
{
                        
throw ex;
                    }



                    
// Get a lock

                    Monitor.Enter(GetCriticalSection);


                    
try
                    
{

                        
// If we have less than max threads currently in the pool

                        
if (GetCurThreadsInPool < GetMaxThreadsInPool)
                        
{

                            
// Should we add a new thread to the pool

                            
if (GetActThreadsInPool == GetCurThreadsInPool)
                            
{

                                
if (IsDisposed == false)
                                
{

                                    
// Create a thread and start it

                                    ThreadStart tsThread 
= new ThreadStart(IOCPFunction);

                                    Thread thThread 
= new Thread(tsThread);

                                    thThread.Name 
= "IOCP " + thThread.GetHashCode();

                                    thThread.Start();


                                    
// Increment the thread pool count

                                    IncCurThreadsInPool();

                                }


                            }


                        }


                    }


                    
catch
                    
{

                    }



                    
// Relase the lock

                    Monitor.Exit(GetCriticalSection);


                    
// Increment the number of active threads

                    DecActThreadsInPool();

                }


            }



            
catch(Exception ex)
            
{
                
string str=ex.Message;

            }



            
// Decrement the thread pool count

            DecCurThreadsInPool();

        }


        
//public void PostEvent(Int32 iValue
        public void PostEvent(int iValue)
        
{

            
try
            
{

                
// Only add work if we are not disposing

                
if (IsDisposed == false)
                
{

                    
unsafe
                    
{

                        
// Post an event into the IOCP Thread Pool

                        PostQueuedCompletionStatus(GetHandle, 
4, (UInt32*) iValue, null);

                    }



                    
// Increment the number of item of work

                    IncCurWorkInPool();


                    
// Get a lock

                    Monitor.Enter(GetCriticalSection);


                    
try
                    
{

                        
// If we have less than max threads currently in the pool

                        
if (GetCurThreadsInPool < GetMaxThreadsInPool)
                        
{

                            
// Should we add a new thread to the pool

                            
if (GetActThreadsInPool == GetCurThreadsInPool)
                            
{

                                
if (IsDisposed == false)
                                
{

                                    
// Create a thread and start it

                                    ThreadStart tsThread 
= new ThreadStart(IOCPFunction);

                                    Thread thThread 
= new Thread(tsThread);

                                    thThread.Name 
= "IOCP " + thThread.GetHashCode();

                                    thThread.Start();


                                    
// Increment the thread pool count

                                    IncCurThreadsInPool();

                                }


                            }


                        }


                    }



                    
catch
                    
{

                    }



                    
// Release the lock

                    Monitor.Exit(GetCriticalSection);

                }


            }



            
catch (Exception e)
            
{

                
throw e;

            }



            
catch
            
{

                
throw new Exception("Unhandled Exception");

            }


        }
  

        
public void PostEvent()
        
{

            
try
            
{

                
// Only add work if we are not disposing

                
if (IsDisposed == false)
                
{

                    
unsafe
                    
{

                        
// Post an event into the IOCP Thread Pool

                        PostQueuedCompletionStatus(GetHandle, 
0nullnull);

                    }



                    
// Increment the number of item of work

                    IncCurWorkInPool();


                    
// Get a lock

                    Monitor.Enter(GetCriticalSection);


                    
try

                    
{

                        
// If we have less than max threads currently in the pool

                        
if (GetCurThreadsInPool < GetMaxThreadsInPool)

                        
{

                            
// Should we add a new thread to the pool

                            
if (GetActThreadsInPool == GetCurThreadsInPool)

                            
{

                                
if (IsDisposed == false)

                                
{

                                    
// Create a thread and start it

                                    ThreadStart tsThread 
= new ThreadStart(IOCPFunction);

                                    Thread thThread 
= new Thread(tsThread);

                                    thThread.Name 
= "IOCP " + thThread.GetHashCode();

                                    thThread.Start();


                                    
// Increment the thread pool count

                                    IncCurThreadsInPool();

                                }


                            }


                        }


                    }



                    
catch

                    
{

                    }



                    
// Release the lock

                    Monitor.Exit(GetCriticalSection);

                }


            }


            
catch

            
{

                
throw new Exception("Unhandled Exception");

            }


        }


    }


}

posted @ 2005-04-13 11:50  老兵笔记  阅读(8434)  评论(7编辑  收藏  举报