异步IO

作者: MagicalGuy | 来源:发表于2018-10-07 14:29 被阅读0次

// 08.异步IO-等待文件对象.cpp : 定义控制台应用程序的入口点。
//

// 每一次文件读取/写入操作，都要创建一个线程，
// 系统同时运行的线程数是有限的，线程的创建和销毁浪费了大量资源
// 没有效率


#include "stdafx.h"
#include <windows.h>
typedef struct _MYOVERLAPPED {
    OVERLAPPED ol;
    HANDLE hFile;
    PBYTE pBuf;
    int nIndex;
}MYOVERLAPPED, *PMYOVERLAPPED;

DWORD WINAPI ThreadProc(LPVOID lParam) {
    PMYOVERLAPPED pol = (PMYOVERLAPPED)lParam;
    printf("开始等待......\n");
    WaitForSingleObject(pol->ol.hEvent, INFINITE);
    for (int i = 0; i < 10; i++)
    {
        printf("%d:%02x \n", pol->nIndex, pol->pBuf[i]);
    }
    printf("读完了！\n");
    return 0;
}

int main()
{
    // 1. 异步IO标记
    // 有了这个标记 该文件就变为可等待的内核对象
    // 后面的read write函数就变为非阻塞的
    HANDLE hFile = CreateFile(L"..\\Debug\\123.exe", GENERIC_READ,
        FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, NULL);
    // 2. 文件读取
    PMYOVERLAPPED pol = new MYOVERLAPPED{};
    pol->ol.Offset = 0x100;// 从偏移0x100这个位置开始读
    pol->ol.hEvent = CreateEvent(NULL,NULL,FALSE,NULL); //系统读取完成后，会把我的hFile变为有信号状态
    pol->hFile = hFile;// 被无视
    pol->pBuf = new BYTE[0x1000]{};
    pol->nIndex = 1;
    ReadFile(hFile,
        pol->pBuf,
        0x1000,
        NULL,//实际读取的个数，由OVERLAPPED结构体指定
        (LPOVERLAPPED)pol);
    HANDLE hThread = CreateThread(NULL, NULL, ThreadProc, pol, NULL, NULL);


    PMYOVERLAPPED pol2 = new MYOVERLAPPED{};
    pol2->ol.Offset = 0x200;// 从偏移0x100这个位置开始读
    pol2->ol.hEvent = CreateEvent(NULL, NULL, FALSE, NULL); //系统读取完成后，会把我的hFile变为有信号状态
    pol2->hFile = hFile;// 被无视
    pol2->pBuf = new BYTE[0x1000]{};
    pol2->nIndex = 2;
    ReadFile(hFile,
        pol2->pBuf,
        0x1000,
        NULL,//实际读取的个数，由OVERLAPPED结构体指定
        (LPOVERLAPPED)pol2);
    HANDLE hThread2 = CreateThread(NULL, NULL, ThreadProc, pol2, NULL, NULL);



    // ......干其他事
    WaitForSingleObject(hThread, INFINITE);
    WaitForSingleObject(hThread2, INFINITE);
    return 0;
}

===========

// 08.异步IO-等待文件对象.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include <windows.h>
typedef struct _MYOVERLAPPED{
    OVERLAPPED ol;
    HANDLE hFile;
    PBYTE pBuf;
    int nIndex;
}MYOVERLAPPED,*PMYOVERLAPPED;

DWORD WINAPI ThreadProc(LPVOID lParam) {
    PMYOVERLAPPED pol = (PMYOVERLAPPED)lParam;
    WaitForSingleObject(pol->hFile, INFINITE);
    for (int i=0;i<10;i++)
    {
        printf("%d:%02x \n", pol->nIndex,pol->pBuf[i]);
    }
    printf("读完了！\n");
    return 0;
}

int main()
{
    // 1. 异步IO标记
    // 有了这个标记 该文件就变为可等待的内核对象
    // 后面的read write函数就变为非阻塞的
    HANDLE hFile = CreateFile(L"..\\Debug\\123.exe", GENERIC_READ,
        FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL| FILE_FLAG_OVERLAPPED, NULL);
    // 2. 文件读取
    PMYOVERLAPPED pol = new MYOVERLAPPED{};
    pol->ol.Offset = 0x100;// 从偏移0x100这个位置开始读
    // pol->hEvent == NULL; 系统读取完成后，会把我的hFile变为有信号状态
    pol->hFile = hFile;
    pol->pBuf = new BYTE[0x1000]{};
    pol->nIndex =1;
    ReadFile(hFile,
        pol->pBuf,
        0x1000,
        NULL,//实际读取的个数，由OVERLAPPED结构体指定
        (LPOVERLAPPED)pol);
    HANDLE hThread = CreateThread(NULL, NULL, ThreadProc, pol, NULL, NULL);
    
    
    PMYOVERLAPPED pol2 = new MYOVERLAPPED{};
    pol2->ol.Offset = 0x200;// 从偏移0x100这个位置开始读
                           // pol->hEvent == NULL; 系统读取完成后，会把我的hFile变为有信号状态
    pol2->hFile = hFile;
    pol2->pBuf = new BYTE[0x1000]{};
    pol2->nIndex = 2;
    ReadFile(hFile,
        pol2->pBuf,
        0x1000,
        NULL,//实际读取的个数，由OVERLAPPED结构体指定
        (LPOVERLAPPED)pol2);
    HANDLE hThread2 = CreateThread(NULL, NULL, ThreadProc, pol2, NULL, NULL);

    
    
    // ......干其他事
    WaitForSingleObject(hThread, INFINITE);
    WaitForSingleObject(hThread2, INFINITE);
    return 0;
}

====================

// 08.异步IO-异步过程调用(APC).cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include <windows.h>
typedef struct _MYOVERLAPPED {
    OVERLAPPED ol;
    HANDLE hFile;
    PBYTE pBuf;
    int nIndex;
}MYOVERLAPPED, *PMYOVERLAPPED;


// 提交任务的线程处理，其他线程看着
VOID CALLBACK FileIOCompletionRoutine(
    _In_    DWORD        dwErrorCode,
    _In_    DWORD        dwNumberOfBytesTransfered,
    _Inout_ LPOVERLAPPED lpOverlapped
) {
    PMYOVERLAPPED pol = (PMYOVERLAPPED)lpOverlapped;
    for (int i = 0; i < 10; i++)
    {
        printf("%d:%02x \n", pol->nIndex, pol->pBuf[i]);
    }
    printf("读完了！\n");
}


int main()
{
    // 1. 异步IO标记
    // 有了这个标记 该文件就变为可等待的内核对象
    // 后面的read write函数就变为非阻塞的
    HANDLE hFile = CreateFile(L"..\\Debug\\123.exe", GENERIC_READ,
        FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, NULL);
    // 2. 文件读取
    PMYOVERLAPPED pol = new MYOVERLAPPED{};
    pol->ol.Offset = 0x100;// 从偏移0x100这个位置开始读
    // hEvent被无视   hFile也被无视
    //pol->ol.hEvent = CreateEvent(NULL, NULL, FALSE, NULL); //系统读取完成后，会把我的hFile变为有信号状态
    pol->hFile = hFile;// 被无视
    pol->pBuf = new BYTE[0x1000]{};
    pol->nIndex = 1;
    ReadFileEx(hFile,
        pol->pBuf,
        0x1000,
        (LPOVERLAPPED)pol,
        FileIOCompletionRoutine);// 完成后直接调用该回调函数，不用等待文件句柄/事件对象

    PMYOVERLAPPED pol2 = new MYOVERLAPPED{};
    pol2->ol.Offset = 0x200;// 从偏移0x100这个位置开始读
    //pol2->ol.hEvent = CreateEvent(NULL, NULL, FALSE, NULL); //系统读取完成后，会把我的hFile变为有信号状态
    //pol2->hFile = hFile;// 被无视
    pol2->pBuf = new BYTE[0x1000]{};
    pol2->nIndex = 2;
    ReadFileEx(hFile,
        pol2->pBuf,
        0x1000,
        (LPOVERLAPPED)pol2,
        FileIOCompletionRoutine);
    // FileIOCompletionRoutine有系统调用
    // 哪个线程执行该函数呢
    // 哪个线程read/write 哪个线程执行
    // ......干其他事

    // 忙完了  想起来还有两个函数等着我呢
    // CPU检测到当前线程的APC队列里有函数需要执行
    // 就去执行该函数，执行完返回
    // 只有当第2个参数是TRUE才去执行
    SleepEx(200, TRUE);
//  WaitForSingleObjectEx()
    return 0;
}

============================

// 08.异步过程调用-完成端口(IOCP).cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include <windows.h>
typedef struct _MYOVERLAPPED {
    OVERLAPPED ol;
    HANDLE hFile;
    PBYTE pBuf;
    int nIndex;
}MYOVERLAPPED, *PMYOVERLAPPED;

DWORD WINAPI ThreadProc(LPVOID lParam) {
    PMYOVERLAPPED pol =nullptr;
    HANDLE hIOCP = lParam;
    while (TRUE)
    {
        DWORD dwNum = 0;
        ULONG_PTR uCompleteKey = 0;
        BOOL bRet = GetQueuedCompletionStatus(
            hIOCP,// 检查完成端口有没有待处理任务(有任务完成，通知完成端口处理)
            &dwNum,// 实际传输的字节数
            &uCompleteKey,// 哪个设备完成了异步操作
            (LPOVERLAPPED*)&pol,
            INFINITE);
        if (bRet == FALSE && ERROR_ABANDONED_WAIT_0 == GetLastError())
        {
            printf("完成端口被关闭\n");
            return 0;
        }
        if (uCompleteKey == NULL && pol == nullptr)
        {
            PostQueuedCompletionStatus(hIOCP, NULL, NULL, NULL);
            printf("完成端口线程结束!\n");
            return 0;
        }
        for (int i = 0; i < 10; i++)
        {
            
            printf("key:%d,%d:%02x \n", uCompleteKey,pol->nIndex, pol->pBuf[i]);
        }
        printf("读完了！\n");
    }
    return 0;
}

int main()
{
    // 1. 异步IO标记
    // 有了这个标记 该文件就变为可等待的内核对象
    // 后面的read write函数就变为非阻塞的
    HANDLE hFile = CreateFile(L"..\\Debug\\123.exe", GENERIC_READ,
        FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, NULL);
    
    // 2. 创建一个完成端口
    // 先获取核心数
    SYSTEM_INFO si = {};
    GetSystemInfo(&si);
    HANDLE hIOCP = CreateIoCompletionPort(
        INVALID_HANDLE_VALUE,// 创建完成端口,绑定完成端口的时候是文件句柄
        NULL,// 创建完成端口的时候是NULL,绑定的时候是完成端口句柄
        NULL,// 创建完成端口的时候是NULL,绑定的时候是自己设置的一个值，用来区分绑定的文件是哪个
        si.dwNumberOfProcessors);// 完成端口上并行运行的最大线程数，绑定的时候是NULL
    // 3.把完成端口和文件绑定，后面这个文件的所有异步操作的通知都交给完成端口
    CreateIoCompletionPort(
        hFile,
        hIOCP,
        0x12,// 和hFile绑定的值，也可以是hFile本身
        NULL
    );
    // 4. 创建完成端口的服务线程
    for (int i=0;i<si.dwNumberOfProcessors*2;i++)
    {
        CreateThread(NULL, NULL, ThreadProc, hIOCP, NULL, NULL);
    }
    
    // 5. 文件读取
    PMYOVERLAPPED pol = new MYOVERLAPPED{};
    pol->ol.Offset = 0x100;// 从偏移0x100这个位置开始读
    pol->pBuf = new BYTE[0x1000]{};
    pol->nIndex = 1;
    ReadFile(hFile,
        pol->pBuf,
        0x1000,
        NULL,//实际读取的个数，由OVERLAPPED结构体指定
        (LPOVERLAPPED)pol);


    PMYOVERLAPPED pol2 = new MYOVERLAPPED{};
    pol2->ol.Offset = 0x200;// 从偏移0x100这个位置开始读
    pol2->pBuf = new BYTE[0x1000]{};
    pol2->nIndex = 2;
    ReadFile(hFile,
        pol2->pBuf,
        0x1000,
        NULL,//实际读取的个数，由OVERLAPPED结构体指定
        (LPOVERLAPPED)pol2);
    // ......干其他事
    // 投递一个完成任务
    PostQueuedCompletionStatus(hIOCP, NULL, NULL, NULL);
    system("pause");
    return 0;
}

异步IO

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