c# - 为什么 TcpClient 这么慢而且 CPU 很饿？

Question

关于我的other question除了现在我尝试异步希望它能解决问题。它没有。

我正在尝试创建一个简单的 SOCKS5 服务器。我将我的浏览器 (firefox) 设置为将此程序用作 SOCKS5。这个想法是一个程序连接到代理服务器，给它所需的信息，服务器只是简单地从一个连接到另一个连接读取/写入数据。这个只是简单地执行此操作，不记录也不过滤任何内容。它非常简单，但由于 CPU 问题以及在您点击几页后连接到站点需要几秒钟的事实使其完全无法使用。这到底是怎么吃掉这么多 CPU 的？为什么连接到站点需要很长时间？异步和同步都受此影响

using System;
using System.Collections.Concurrent;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Net.Sockets;
using System.Timers;
using System.IO;
using System.Net;
using System.Threading;

namespace ProxyTest
{
    class Program
    {
        static ManualResetEvent tcpClientConnected =new ManualResetEvent(false);
        static void Main(string[] args)
        {
            var s2 = new TcpListener(9998);
            s2.Start();
            Task.Run(() =>
            {
                while (true)
                {
                    tcpClientConnected.Reset();
                    s2.BeginAcceptTcpClient(Blah, s2);
                    tcpClientConnected.WaitOne();
                }
            });
            while (true)
                System.Threading.Thread.Sleep(10000000);
        }

        static void Blah(IAsyncResult ar)
        {
            try
            {
                Console.WriteLine("Connection");
                TcpListener listener = (TcpListener)ar.AsyncState;
                using (var socketin = listener.EndAcceptTcpClient(ar))
                {
                    tcpClientConnected.Set();
                    var ns1 = socketin.GetStream();
                    var r1 = new BinaryReader(ns1);
                    var w1 = new BinaryWriter(ns1);

                    if (false)
                    {
                        var s3 = new TcpClient();
                        s3.Connect("127.0.0.1", 9150);
                        var ns3 = s3.GetStream();
                        var r3 = new BinaryReader(ns3);
                        var w3 = new BinaryWriter(ns3);
                        while (true)
                        {
                            while (ns1.DataAvailable)
                            {
                                var b = ns1.ReadByte();
                                w3.Write((byte)b);
                                //Console.WriteLine("1: {0}", b);
                            }
                            while (ns3.DataAvailable)
                            {
                                var b = ns3.ReadByte();
                                w1.Write((byte)b);
                                Console.WriteLine("2: {0}", b);
                            }
                        }
                    }

                    {
                        if (!(r1.ReadByte() == 5 && r1.ReadByte() == 1))
                            return;
                        var c = r1.ReadByte();
                        for (int i = 0; i < c; ++i)
                            r1.ReadByte();
                        w1.Write((byte)5);
                        w1.Write((byte)0);
                    }
                    {
                        if (!(r1.ReadByte() == 5 && r1.ReadByte() == 1))
                            return;
                        if (r1.ReadByte() != 0)
                            return;
                    }
                    byte[] ipAddr = null;
                    string hostname = null;
                    var type = r1.ReadByte();
                    switch (type)
                    {
                        case 1:
                            ipAddr = r1.ReadBytes(4);
                            break;
                        case 3:
                            hostname = Encoding.ASCII.GetString(r1.ReadBytes(r1.ReadByte()));
                            break;
                        case 4:
                            throw new Exception();
                    }
                    var nhport = r1.ReadInt16();
                    var port = IPAddress.NetworkToHostOrder(nhport);

                    var socketout = new TcpClient();
                    if (hostname != null)
                        socketout.Connect(hostname, port);
                    else
                        socketout.Connect(new IPAddress(ipAddr), port);

                    w1.Write((byte)5);
                    w1.Write((byte)0);
                    w1.Write((byte)0);
                    w1.Write(type);
                    switch (type)
                    {
                        case 1:
                            w1.Write(ipAddr);
                            break;
                        case 2:
                            w1.Write((byte)hostname.Length);
                            w1.Write(Encoding.ASCII.GetBytes(hostname), 0, hostname.Length);
                            break;
                    }
                    w1.Write(nhport);

                    var buf1 = new byte[4096];
                    var buf2 = new byte[4096];
                    var ns2 = socketout.GetStream();
                    var r2 = new BinaryReader(ns2);
                    var w2 = new BinaryWriter(ns2);
                    Task.Run(() =>
                    {
                        var re = new ManualResetEvent(false);
                        while (true)
                        {
                            re.Reset();
                            ns1.BeginRead(buf1, 0, buf1.Length, ReadCallback, new A() { buf = buf1, thisSocket = socketin, otherSocket = socketout, thisStream = ns1, otherStream = ns2, re=re });
                            re.WaitOne();
                        }
                    });
                    Task.Run(() =>
                    {
                        var re = new ManualResetEvent(false);
                        while (true)
                        {
                            re.Reset();
                            ns2.BeginRead(buf2, 0, buf2.Length, ReadCallback, new A() { buf = buf2, thisSocket = socketout, otherSocket = socketin, thisStream = ns2, otherStream = ns1, re = re });
                            re.WaitOne();
                        }
                    });
                    while (true)
                    {
                        if (socketin.Connected == false)
                            return;
                        Thread.Sleep(100);
                    }
                }
            }
            catch { }
        }
        class A { public byte[] buf; public TcpClient thisSocket, otherSocket; public NetworkStream thisStream, otherStream; public ManualResetEvent re;};
        static void ReadCallback(IAsyncResult ar)
        {
            try
            {
                var a = (A)ar.AsyncState;
                var ns1 = a.thisStream;
                var len = ns1.EndRead(ar);
                a.otherStream.Write(a.buf, 0, len);
                a.re.Set();
            }
            catch
            {
            }
        }
    }
}

Answer 1

警告:由于我没有使用 4.5，所以我不得不稍微调整一下。

Task.Run() --> new Thread().Start()

您使用的线程太多。 简单地尝试在 stackoverflow 中加载这个问题会导致 30 多个线程产生，这会重现使用 Task.Run() 时看到的行为。

随着您的代码减少到每个连接一个线程，我的 CPU 使用率徘徊在 0% 左右。一切加载迅速。

using System;
using System.Collections.Generic;
using System.Collections.Concurrent;
using System.ComponentModel;
using System.Data;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Net.Sockets;
using System.Timers;
using System.IO;
using System.Net;
using System.Threading;

namespace SOCKS5
{
    static class Program
    {
        static void Main()
        {
            var s2 = new TcpListener(9998);
            s2.Start();

            while (true)
            {
                if (s2.Pending())
                {
                    Thread test = new Thread(() =>
                    {
                        using (TcpClient client = s2.AcceptTcpClient())
                        {
                            Blah(client);
                        }
                    });

                    test.Start();
                }

                Thread.Sleep(10);
            }
        }

        static void Blah(TcpClient listener)
        {
            try
            {
                Console.WriteLine("Connection");
                //TcpListener listener = (TcpListener)ar.AsyncState;


                //tcpClientConnected.Set();
                var ns1 = listener.GetStream();
                var r1 = new BinaryReader(ns1);
                var w1 = new BinaryWriter(ns1);

                if (false)
                {
                    var s3 = new TcpClient();
                    s3.Connect("127.0.0.1", 9150);
                    var ns3 = s3.GetStream();
                    var r3 = new BinaryReader(ns3);
                    var w3 = new BinaryWriter(ns3);
                    while (true)
                    {
                        while (ns1.DataAvailable)
                        {
                            var b = ns1.ReadByte();
                            w3.Write((byte)b);
                            //Console.WriteLine("1: {0}", b);
                        }
                        while (ns3.DataAvailable)
                        {
                            var b = ns3.ReadByte();
                            w1.Write((byte)b);
                            Console.WriteLine("2: {0}", b);
                        }
                    }
                }

                {
                    if (!(r1.ReadByte() == 5 && r1.ReadByte() == 1))
                        return;
                    var c = r1.ReadByte();
                    for (int i = 0; i < c; ++i)
                        r1.ReadByte();
                    w1.Write((byte)5);
                    w1.Write((byte)0);
                }
                {
                    if (!(r1.ReadByte() == 5 && r1.ReadByte() == 1))
                        return;
                    if (r1.ReadByte() != 0)
                        return;
                }
                byte[] ipAddr = null;
                string hostname = null;
                var type = r1.ReadByte();
                switch (type)
                {
                    case 1:
                        ipAddr = r1.ReadBytes(4);
                        break;
                    case 3:
                        hostname = Encoding.ASCII.GetString(r1.ReadBytes(r1.ReadByte()));
                        break;
                    case 4:
                        throw new Exception();
                }
                var nhport = r1.ReadInt16();
                var port = IPAddress.NetworkToHostOrder(nhport);

                var socketout = new TcpClient();
                if (hostname != null)
                    socketout.Connect(hostname, port);
                else
                    socketout.Connect(new IPAddress(ipAddr), port);

                w1.Write((byte)5);
                w1.Write((byte)0);
                w1.Write((byte)0);
                w1.Write(type);
                switch (type)
                {
                    case 1:
                        w1.Write(ipAddr);
                        break;
                    case 2:
                        w1.Write((byte)hostname.Length);
                        w1.Write(Encoding.ASCII.GetBytes(hostname), 0, hostname.Length);
                        break;
                }
                w1.Write(nhport);

                var buf1 = new byte[4096];
                var buf2 = new byte[4096];
                var ns2 = socketout.GetStream();

                DateTime last = DateTime.Now;

                while ((DateTime.Now - last).TotalMinutes < 5.0)
                {
                    if (ns1.DataAvailable)
                    {
                        int size = ns1.Read(buf1, 0, buf1.Length);
                        ns2.Write(buf1, 0, size);
                        last = DateTime.Now;
                    }
                    if (ns2.DataAvailable)
                    {
                        int size = ns2.Read(buf2, 0, buf2.Length);
                        ns1.Write(buf2, 0, size);
                        last = DateTime.Now;
                    }

                    Thread.Sleep(10);
                }
            }
            catch { }
            finally
            {
                try
                {
                    listener.Close();
                }
                catch (Exception) { }
            }
        }
    }
}

编辑:

这最终变得有点有趣。

在通过它路由 Firefox 流量几个小时后，一些观察结果。

从未注意到确定何时关闭连接的常规模式。让线程在闲置 5 分钟(无 rx/tx)后终止可使线程数保持在相当低的水平。这是一个非常安全的界限，允许 gmail 聊天等服务继续运行。

由于某些原因，程序偶尔会收不到浏览器的请求，从而报超时。程序中没有关于错过请求的通知，什么都没有。只在浏览 stackoverflow 时注意到。仍然没有想出那个。