Question

当从不同的线程为不同的URL调用HttpWebRequest.GetResponse方法时，我的表现非常糟糕。例如，如果我们有一个线程并执行url1，则需要3秒。如果我们在parallet中执行url1和url2，则需要10秒，第一个请求在8秒后结束，第二个请求在10秒后结束。

如果我们将10个网址exlt url1，url2，... url0，则需要1分4秒！第一次请求在50秒后结束！

我使用GetResponse方法。我尝试了设置DefaultConnectionLimit，但它没有帮助。如果使用BeginGetRequest / EndGetResponse方法，它的工作速度非常快，但只有在从一个线程调用此方法时才能使用。如果从不同的方面它也很慢。我需要一次从多个线程执行Http请求。

在每个线程中执行相同的代码。如果只有一个线程GetResponse方法工作得非常快。 URL中的IP地址对于每个线程也是不同的。如果您编译并运行以下代码，您将看到逐个处理的请求。拳头执行3秒，第二个8秒，第三个15秒.... 即没有多线程的收益。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.IO;
using System.Xml;
using System.Reflection;
using System.Threading;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Collections;

namespace HttpRequestExample
{

    class HttpPerformer
    {
        private Thread thread = null;
        HttpWebRequest httpRequest = null;

        public void start(string url)
        {
            thread = new Thread(new ThreadStart(WorkerThread));
            thread.Name = url;
            thread.Start();

        }

        public void WorkerThread()
        {
            try
            {
                HttpWebRequest req = (HttpWebRequest)WebRequest.Create((string)thread.Name);
                Console.WriteLine(DateTime.Now + " : before get response " + thread.Name);
                HttpWebResponse resp = (HttpWebResponse)req.GetResponse();
                Console.WriteLine(DateTime.Now + " : after get response " + thread.Name);

            }
            catch (Exception e)
            {
                Console.WriteLine(DateTime.Now + " : Exception : " + e.Message + thread.Name);
            }
        }
    }

    class HttpAccessUtils
    {
        public static bool SetAllowUnsafeHeaderParsing20()
        {
            //Get the assembly that contains the internal class 
            Assembly aNetAssembly = Assembly.GetAssembly(typeof(System.Net.Configuration.SettingsSection));
            if (aNetAssembly != null)
            {
                //Use the assembly in order to get the internal type for the internal class 
                Type aSettingsType = aNetAssembly.GetType("System.Net.Configuration.SettingsSectionInternal");
                if (aSettingsType != null)
                {
                    //Use the internal static property to get an instance of the internal settings class. 
                    //If the static instance isn't created allready the property will create it for us. 
                    object anInstance = aSettingsType.InvokeMember("Section",
                    BindingFlags.Static | BindingFlags.GetProperty | BindingFlags.NonPublic, null, null, new object[] { });

                    if (anInstance != null)
                    {
                        //Locate the private bool field that tells the framework is unsafe header parsing should be allowed or not 
                        FieldInfo aUseUnsafeHeaderParsing = aSettingsType.GetField("useUnsafeHeaderParsing", BindingFlags.NonPublic | BindingFlags.Instance);
                        if (aUseUnsafeHeaderParsing != null)
                        {
                            aUseUnsafeHeaderParsing.SetValue(anInstance, true);
                            return true;
                        }
                    }
                }
            }
            return false;
        }
    }

    class Program
    {

        static void Main(string[] args)
        {
            HttpAccessUtils.SetAllowUnsafeHeaderParsing20();
            ServicePointManager.UseNagleAlgorithm = true;
            ServicePointManager.Expect100Continue = true;
            ServicePointManager.CheckCertificateRevocationList = true;
            ServicePointManager.DefaultConnectionLimit = 200; //ServicePointManager.DefaultPersistentConnectionLimit;
            ServicePointManager.MaxServicePoints = 100;
            Console.WriteLine(ServicePointManager.MaxServicePoints);


            ArrayList a = new ArrayList(150);

            for (int i = 100; i < 220; i++)
            {
                a.Add("http://207.242.7." + i.ToString());
            }

            for (int i = 0; i < a.Count; i++)
            {
                HttpPerformer hp = new HttpPerformer();
                hp.start((string)a[i]);
            }

        }

        static void performRequest(object url)
        {
            try
            {
                HttpWebRequest req = (HttpWebRequest)WebRequest.Create((string)url);
                Console.WriteLine(DateTime.Now + " : before get response " + url);
                HttpWebResponse resp = (HttpWebResponse)req.GetResponse();
                Console.WriteLine(DateTime.Now + " : after get response " + url);
            }
            catch (Exception e)
            {
                Console.WriteLine(DateTime.Now + " : Exception : " + e.Message + (string)url);
            }

        }
    }
}

任何人遇到过这样的问题？感谢您的任何建议。

Answer 1

获取响应流后，您需要关闭conn ，否则连接将保持打开状态很长时间。这可能是缓慢的原因。

Answer 2

您需要在收到回复后关闭连接。这似乎导致了这个问题。

多线程应用程序中HttpWebRequest.GetResponse性能的问题

2 个答案: