C++ TCP 套接字发送速度

Question

我使用简单的锁定 TCP 套接字将消息发送到远程服务器，我遇到的问题是，对于每条消息，发送它需要非常不同的时间。

这是我得到的（一些例子）：

Bytes Sent:  217, Time:  34.3336 usec
Bytes Sent:  217, Time:   9.9107 usec
Bytes Sent:  226, Time:  20.1754 usec
Bytes Sent:  226, Time:  38.2271 usec
Bytes Sent:  217, Time:  33.6257 usec
Bytes Sent:  217, Time:  12.7424 usec
Bytes Sent:  217, Time:  21.5912 usec
Bytes Sent:  217, Time:  31.1480 usec
Bytes Sent:  218, Time:  28.3164 usec
Bytes Sent:  218, Time:  13.0963 usec
Bytes Sent:  218, Time:  82.8254 usec
Bytes Sent:  218, Time:  13.0963 usec
Bytes Sent:  227, Time:  30.7941 usec
Bytes Sent:  218, Time:  27.9624 usec
Bytes Sent:  216, Time:   2.1237 usec
Bytes Sent:  218, Time:  12.3884 usec
Bytes Sent:  227, Time:  31.1480 usec
Bytes Sent:  227, Time:  88.4887 usec
Bytes Sent:  218, Time:  93.0901 usec
Bytes Sent:  218, Time:   7.7870 usec
Bytes Sent:  218, Time:  28.3164 usec
Bytes Sent:  227, Time:  89.5505 usec
Bytes Sent:  218, Time:  84.2412 usec
Bytes Sent:  218, Time:  13.8042 usec
Bytes Sent:  227, Time:  99.4612 usec
Bytes Sent:  218, Time:  86.0110 usec
Bytes Sent:  218, Time:  12.3884 usec
Bytes Sent:  218, Time:  87.7807 usec
Bytes Sent:  216, Time:   3.5395 usec
Bytes Sent:  218, Time:   4.6014 usec
Bytes Sent:  218, Time:  36.1034 usec
Bytes Sent:  218, Time:  14.8661 usec
Bytes Sent:  218, Time:  24.0689 usec
Bytes Sent:  218, Time:  18.0517 usec
Bytes Sent:  227, Time:  24.4229 usec

有谁知道为什么会发生这种情况？为什么发送一条消息需要 3 微秒，而其他 80 微秒？
有没有办法解决这个问题？

注意：我要存档的主要目标是尽快发送每条消息。我不需要任何同步套接字，至少在它们工作得更快之前。

关于我的工作的一些额外细节：

C++、Visual Studio 2013

我如何打开：

...
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
...
ConnectSocket = socket(ptr->ai_family, ptr->ai_socktype, ptr->ai_protocol);
...

我如何发送和计算时间：

...
LARGE_INTEGER cT;
QueryPerformanceCounter(&cT);
long long dT = cT.QuadPart;

iBytesSent = send(ConnectSocket, msgFinal, msgFinalLen, 0);

QueryPerformanceCounter(&cT);
dT = cT.QuadPart - dT;
...

另外我正在从其他线程监听这个套接字，我不知道这是否会影响发送：

iResult = recv(ConnectSocket, recvbuf, DEFAULT_BUFLEN, 0);

Answer 1

你的方法无效。您只是在测量将数据放入发送缓冲区所需的时间。如果有它的空间，则根本没有网络操作。如果没有空间，则阻塞直到有空间，这取决于接收器读取已经存在的内容。所以你看到的是，有时有空间，有时没有，这取决于接收器是否正在阅读和跟上。

如果你想测量往返时间，你需要发送一个时间戳并让对端回显它，然后当你收到它时将它与当前时间进行比较。