讨论：GetProcessIoCounters中的IO到底指的是什么IO

[沙老师]

在做一个应用程序性能测量的程序，用到了这个函数，令人诧异的是，GOOGLE搜了个底朝天，根本没有关于其IO到底什么含义的详细解释，只有少数地方含糊地提到包含文件、网络等IO，无奈只得自己做实验，写了如下测试程序：

#include <windows.h>
#include <stdio.h>
#include <process.h>

void printIoDelta() {
    static DWORD lastTickCount;
    static IO_COUNTERS lastIoCounters;
    DWORD tickCount;
    IO_COUNTERS ioCounters;
    static int firstTime = 1;

    tickCount = GetTickCount();
    if (!GetProcessIoCounters(GetCurrentProcess(), &ioCounters)) {
        return;
    }

    if (firstTime) {
        firstTime = 0;
        printf("    Time    Read   Write   Other     Read(Bytes)    Write(Bytes)    Other(Bytes)\n");
        printf("--------------------------------------------------------------------------------\n");
    } else {
        printf("%8lu%8llu%8llu%8llu%16llu%16llu%16llu\n",
            tickCount - lastTickCount,
            ioCounters.ReadOperationCount - lastIoCounters.ReadOperationCount,
            ioCounters.WriteOperationCount - lastIoCounters.WriteOperationCount,
            ioCounters.OtherOperationCount - lastIoCounters.OtherOperationCount,
            ioCounters.ReadTransferCount - lastIoCounters.ReadTransferCount,
            ioCounters.WriteTransferCount - lastIoCounters.WriteTransferCount,
            ioCounters.OtherTransferCount - lastIoCounters.OtherTransferCount
            );
    }

    lastTickCount = tickCount;
    memcpy(&lastIoCounters, &ioCounters, sizeof(IO_COUNTERS));
}

void workerThread(void * dummy) {
    int i;
    FILE * fp;
    char buff[500000];
    WSADATA wsaData;
    SOCKET s;
    struct sockaddr_in localAddr;
    struct sockaddr_in peerAddr;

    memset(buff, 'X', sizeof(buff));

    Sleep(2000);

    // 写文件
    fp = fopen("io.txt", "w");
    if (fp) {
        printf("fwrite = %d\n", fwrite(buff, 1, sizeof(buff), fp));
        Sleep(10000);
        // 关闭文件，测试Flush
        printf("fclose\n");
        fclose(fp);
        Sleep(2000);
    }

    // 读文件
    fp = fopen("io.txt", "r");
    if (fp) {
        printf("fread = %d\n", fread(buff, 1, sizeof(buff), fp));
        fclose(fp);
        Sleep(2000);
    }

    // 网络发

    memset((void *)&localAddr, 0, sizeof(localAddr));
    localAddr.sin_family = AF_INET;
    localAddr.sin_addr.s_addr = htonl(INADDR_ANY);
    localAddr.sin_port = htons(0);
    memset((void *)&peerAddr, 0, sizeof(peerAddr));
    peerAddr.sin_family = AF_INET;
    peerAddr.sin_addr.s_addr = inet_addr("10.65.19.7");
    peerAddr.sin_port = htons(3389);

    printf("WSAStartup\n");
    WSAStartup(MAKEWORD(2, 2), &wsaData);
    Sleep(2000);

    // UDP
    printf("socket\n");
    s = socket(AF_INET, SOCK_DGRAM, 0);
    Sleep(2000);

    printf("bind\n");
    bind(s, (struct sockaddr *)&localAddr, sizeof(localAddr));
    Sleep(2000);
    for (i = 0; i < 20; i++) {
        printf("sendto = %d\n", sendto(s, buff, i * 100, 0, (SOCKADDR *) &peerAddr, sizeof(peerAddr)));
        Sleep(2000);
    }
    printf("closesocket\n");
    closesocket(s);
    Sleep(2000);

    // TCP
    printf("socket\n");
    s = socket(AF_INET, SOCK_STREAM, 0);
    Sleep(2000);
    
    printf("bind\n");
    bind(s, (struct sockaddr *)&localAddr, sizeof(localAddr));
    Sleep(2000);

    printf("connect\n");
    connect(s, (SOCKADDR *) &peerAddr, sizeof(peerAddr));
    Sleep(2000);

    printf("send = %d\n", send(s, buff, sizeof(buff), 0));
    Sleep(2000);

    printf("closesocket\n");
    closesocket(s);
    Sleep(2000);

    printf("WSACleanup\n");
    WSACleanup();
}

int main(int argc, char ** argv) {
    // 启动工作线程
    _beginthread(workerThread, 0, 0);

    printf("Ctrl-C to exit\n\n");
    for (;;) {
        printIoDelta();
        Sleep(1000);
    }
    return 0;
}

其原理是在主线程中每隔1秒输出GetProcessIoCounters获取的6和数值相对于上1秒的差值，然后在工作线程中文件读写、TCP和UDP的发送操作。

[沙老师]

我记录下了程序的输出，非常诡异：

Ctrl-C to exit

    Time    Read   Write   Other     Read(Bytes)    Write(Bytes)    Other(Bytes)
--------------------------------------------------------------------------------
    1000       0       0       0               0               0               0
    1000       0       0       0               0               0               0
fwrite = 500000
    1000       0      98       1               0          499712               0
    1000       0       0       0               0               0               0
    1000       0       0       0               0               0               0
    1000       0       0       0               0               0               0
    1000       0       0       0               0               0               0
    1000       0       0       0               0               0               0
    1000       0       0       0               0               0               0
    1000       0       0       0               0               0               0
    1000       0       0       0               0               0               0
    1000       0       0       0               0               0               0
fclose
    1000       0       1       1               0             288               0
    1000       0       0       0               0               0               0
fread = 500000
    1000       2       0       2          500000               0               0
    1000       0       0       0               0               0               0
WSAStartup
    1000       0       0       0               0               0               0
    1000       0       0       0               0               0               0
socket
    1000       0       0      37               0               0               0
    1000       0       0       0               0               0               0
bind
    1000       1       1      22              68              72            4270
    1000       0       0       0               0               0               0
sendto = 0
    1000       0       0       0               0               0               0
    1000       0       0       0               0               0               0
sendto = 100
    1000       0       0       0               0               0               0
    1000       0       0       0               0               0               0
sendto = 200
    1000       0       0       0               0               0               0
    1000       0       0       0               0               0               0
sendto = 300
    1000       0       0       0               0               0               0
    1000       0       0       0               0               0               0
sendto = 400
    1000       0       0       0               0               0               0
    1000       0       0       0               0               0               0
sendto = 500
    1000       0       0       0               0               0               0
    1000       0       0       0               0               0               0
sendto = 600
    1000       0       0       0               0               0               0
    1000       0       0       0               0               0               0
sendto = 700
    1000       0       0       0               0               0               0
    1000       0       0       0               0               0               0
sendto = 800
    1000       0       0       0               0               0               0
    1000       0       0       0               0               0               0
sendto = 900
    1000       0       0       0               0               0               0
    1000       0       0       0               0               0               0
sendto = 1000
    1000       0       0       0               0               0               0
    1000       0       0       0               0               0               0
sendto = 1100
    1000       0       0       1               0               0            1100
    1000       0       0       0               0               0               0
sendto = 1200
    1000       0       0       1               0               0            1200
    1000       0       0       0               0               0               0
sendto = 1300
    1000       0       0       1               0               0            1300
    1000       0       0       0               0               0               0
sendto = 1400
    1000       0       0       1               0               0            1400
    1000       0       0       0               0               0               0
sendto = 1500
    1000       0       0       1               0               0            1500
    1000       0       0       0               0               0               0
sendto = 1600
    1000       0       0       1               0               0            1600
    1000       0       0       0               0               0               0
sendto = 1700
    1000       0       0       1               0               0            1700
    1000       0       0       0               0               0               0
sendto = 1800
    1000       0       0       1               0               0            1800
    1000       0       0       0               0               0               0
sendto = 1900
    1000       0       0       1               0               0            1900
    1000       0       0       0               0               0               0
closesocket
    1000       0       0       1               0               0               0
    1000       0       0       0               0               0               0
socket
    1000       0       0       1               0               0               0
    1000       0       0       0               0               0               0
bind
    1000       0       0       2               0               0            1944
    1000       0       0       0               0               0               0
connect
    1000       0       0       2               0               0               0
    1000       0       0       0               0               0               0
send = 500000
    1000       0       0       0               0               0               0
    1000       0       0       0               0               0               0
closesocket
    1000       0       0       1               0               0               0
    1000       0       0       0               0               0               0
WSACleanup
    1000       0       0       0               0               0               0
    1000       0       0       0               0               0               0
    1000       0       0       0               0               0               0
    1000       0       0       0               0               0               0
    1000       0       0       0               0               0               0
^C

前面的文件读写和预料的差不多，写文件因为有缓存的存在，可以看到，直到fclose才将缓存中剩下的一点点内容写道硬盘中。

TCP和UDP的发送操作根本没有产生任何IO，这是令我最为不解的，只有bind时候产生了一些Others IO，另外UDP发送报文长度大于1000产生Others IO的原因后来也找到了：报文根本没有发出去，传回来的都是ICMP。

还有，我对比了任务管理器中有关IO的6栏，和GetProcessIoCounters返回的值是一致的，而任务管理器中的帮助明明写的是IO Read和IO Write是包含网络数据的，真TMD搞不懂了！！！

[IsItNothing]

你在系统的性能管理器里查看就可以验证你的程序了。

[fishion]

in-out不就是输入，输出吗

[沙老师]

[Quote=引用 3 楼 fishion 的回复:]

in-out不就是输入，输出吗
[/Quote]

关键问题是为什么GetProcessIoCounters获取的值不包含网络IO...

[fishion]

应该包含吧，难道是没发送成功了，所以就没显示？你写个客户端让这个程序进行通信行不

[沙老师]

[Quote=引用 9 楼 sevencat 的回复:]
不绑定本地端口，连另一台机器试试。
[/Quote]

10.65.19.7是另外一台机器，我的机器是10.65.19.30，TCP和UDP的Socket肯定是要绑定本地IP地址和端口的...

[沙老师]

我用任务管理器观察了我们的一些网络通信程序（没有磁盘文件或数据库交互），其IO读写确实没有什么变化...更加确定了其IO是不包含网络的

[沙老师]

http://technet.microsoft.com/en-us/library/cc749980.aspx

这里写道：

The Windows NT I/O architecture not only supports traditional file systems but has implemented its network redirector and server as file system drivers. The I/O Manager sees no difference between accessing files stored on a remote networked computer and accessing those stored locally on a hard disk. In addition, redirectors and servers can be loaded and unloaded dynamically, just like any other driver, and multiple redirectors and servers can coexist on the same computer.

从中可以猜测出所谓IO所包含的“网络”指的是类似于“网上邻居”之类的东西，Windows底层把它们等同于本地文件对待的

[沙老师]

[Quote=引用 5 楼 fishion 的回复:]

应该包含吧，难道是没发送成功了，所以就没显示？你写个客户端让这个程序进行通信行不
[/Quote]

应该发送成功了，我用抓包工具测过，另外程序显示的“sendto = ”和“send = ”就是这两个函数的返回值...今天再测一测，如果还是如此的话那只能按照这个经验性的结果往下做了...

[jwybobo2007]

应该属于

[sevencat]

不绑定本地端口，连另一台机器试试。

[zyrr159487]

获取进程的I/O相关操作

[野男孩]

嗯，果然。我也验证了一下，tcp的send和recv的流量都没有计算在这个I/O里面。