我有一个WPF应用程序，遇到很多性能问题。最糟糕的是，有时应用程序会冻结几秒钟，然后再次运行。

我目前正在调试该应用程序，以查看此冻结可能与之相关，并且我认为可能导致此冻结的原因之一是垃圾收集器。由于我的应用程序在非常有限的环境中运行，因此我相信垃圾收集器在运行时可以使用机器的所有资源，而不会将任何资源留给我们的应用程序。

为了验证这一假设，我找到了以下文章:Garbage Collection Notifications和Garbage Collection Notifications in .NET 4.0，它们解释了如何在垃圾收集器开始运行以及何时完成时通知我的应用程序。

因此，基于这些文章，我创建了以下类以获取通知:

public sealed class GCMonitor
{
    private static volatile GCMonitor instance;
    private static object syncRoot = new object();

    private Thread gcMonitorThread;
    private ThreadStart gcMonitorThreadStart;

    private bool isRunning;

    public static GCMonitor GetInstance()
    {
        if (instance == null)
        {
            lock (syncRoot)
            {
                instance = new GCMonitor();
            }
        }

        return instance;
    }

    private GCMonitor()
    {
        isRunning = false;
        gcMonitorThreadStart = new ThreadStart(DoGCMonitoring);
        gcMonitorThread = new Thread(gcMonitorThreadStart);
    }

    public void StartGCMonitoring()
    {
        if (!isRunning)
        {
            gcMonitorThread.Start();
            isRunning = true;
            AllocationTest();
        }
    }

    private void DoGCMonitoring()
    {
        long beforeGC = 0;
        long afterGC = 0;

        try
        {

            while (true)
            {
                // Check for a notification of an approaching collection.
                GCNotificationStatus s = GC.WaitForFullGCApproach(10000);
                if (s == GCNotificationStatus.Succeeded)
                {
                    //Call event
                    beforeGC = GC.GetTotalMemory(false);
                    LogHelper.Log.InfoFormat("===> GC <=== " + Environment.NewLine + "GC is about to begin. Memory before GC: %d", beforeGC);
                    GC.Collect();

                }
                else if (s == GCNotificationStatus.Canceled)
                {
                    LogHelper.Log.Info("===> GC <=== " + Environment.NewLine + "GC about to begin event was cancelled");
                }
                else if (s == GCNotificationStatus.Timeout)
                {
                    LogHelper.Log.Info("===> GC <=== " + Environment.NewLine + "GC about to begin event was timeout");
                }
                else if (s == GCNotificationStatus.NotApplicable)
                {
                    LogHelper.Log.Info("===> GC <=== " + Environment.NewLine + "GC about to begin event was not applicable");
                }
                else if (s == GCNotificationStatus.Failed)
                {
                    LogHelper.Log.Info("===> GC <=== " + Environment.NewLine + "GC about to begin event failed");
                }

                // Check for a notification of a completed collection.
                s = GC.WaitForFullGCComplete(10000);
                if (s == GCNotificationStatus.Succeeded)
                {
                    //Call event
                    afterGC = GC.GetTotalMemory(false);
                    LogHelper.Log.InfoFormat("===> GC <=== " + Environment.NewLine + "GC has ended. Memory after GC: %d", afterGC);

                    long diff = beforeGC - afterGC;

                    if (diff > 0)
                    {
                        LogHelper.Log.InfoFormat("===> GC <=== " + Environment.NewLine + "Collected memory: %d", diff);
                    }

                }
                else if (s == GCNotificationStatus.Canceled)
                {
                    LogHelper.Log.Info("===> GC <=== " + Environment.NewLine + "GC finished event was cancelled");
                }
                else if (s == GCNotificationStatus.Timeout)
                {
                    LogHelper.Log.Info("===> GC <=== " + Environment.NewLine + "GC finished event was timeout");
                }
                else if (s == GCNotificationStatus.NotApplicable)
                {
                    LogHelper.Log.Info("===> GC <=== " + Environment.NewLine + "GC finished event was not applicable");
                }
                else if (s == GCNotificationStatus.Failed)
                {
                    LogHelper.Log.Info("===> GC <=== " + Environment.NewLine + "GC finished event failed");
                }

                Thread.Sleep(1500);
            }
        }
        catch (Exception e)
        {
            LogHelper.Log.Error("  ********************   Garbage Collector Error  ************************ ");
            LogHelper.LogAllErrorExceptions(e);
            LogHelper.Log.Error("  -------------------   Garbage Collector Error  --------------------- ");
        }
    }

    private void AllocationTest()
    {
        // Start a thread using WaitForFullGCProc.
        Thread stress = new Thread(() =>
        {
            while (true)
            {
                List<char[]> lst = new List<char[]>();

                try
                {
                    for (int i = 0; i <= 30; i++)
                    {
                        char[] bbb = new char[900000]; // creates a block of 1000 characters
                        lst.Add(bbb);                // Adding to list ensures that the object doesnt gets out of scope
                    }

                    Thread.Sleep(1000);
                }
                catch (Exception ex)
                {
                    LogHelper.Log.Error("  ********************   Garbage Collector Error  ************************ ");
                    LogHelper.LogAllErrorExceptions(e);
                    LogHelper.Log.Error("  -------------------   Garbage Collector Error  --------------------- ");
                }
            }


        });
        stress.Start();
    }
}

<?xml version="1.0"?>
<configuration>
  <configSections>
    <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net-net-2.0"/>
  </configSections>

  <runtime>
    <gcConcurrent enabled="false" />
  </runtime>

  <log4net>
    <appender name="Root.ALL" type="log4net.Appender.RollingFileAppender">
      <param name="File" value="../Logs/Root.All.log"/>
      <param name="AppendToFile" value="true"/>
      <param name="MaxSizeRollBackups" value="10"/>
      <param name="MaximumFileSize" value="8388608"/>
      <param name="RollingStyle" value="Size"/>
      <param name="StaticLogFileName" value="true"/>
      <layout type="log4net.Layout.PatternLayout">
      <param name="ConversionPattern" value="%date [%thread] %-5level - %message%newline"/>
      </layout>
    </appender>
    <root>
      <level value="ALL"/>
      <appender-ref ref="Root.ALL"/>
    </root>
  </log4net>

  <appSettings>
    <add key="setting1" value="1"/>
    <add key="setting2" value="2"/>
  </appSettings>
  <startup>
    <supportedRuntime version="v2.0.50727"/>
  </startup>

</configuration>

最佳答案

在您的代码中的任何地方都看不到 GC.RegisterForFullGCNotification(int,int) 。看起来您正在使用WaitForFullGC[xxx]方法，但从未注册该通知。这可能就是为什么您获得“不适用”状态的原因。

但是，我怀疑GC是您的问题，尽管可能，但我想最好了解其中存在的所有GC模式以及确定正在发生的最佳方法。 .NET中有两种垃圾收集模式:服务器和工作站。它们都收集相同的未使用内存，但是其完成方式却稍有不同。

关于c# - 在C#中监视垃圾收集器，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/9669963/