知识大全 .Net 下跟踪线程挂起和程序死循环

Posted 2022-07-17 知

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　　下的程序调试相对C/C++要简单很多少了那些令人头疼的指针越界的问题不过当你的程序遇到如下问题时依然非常棘手

　　进程异常终止解决方案见 Net 下未捕获异常的处理

　　内存泄漏或者内存申请后程序始终没有释放解决方案见用 NET Memory Profiler 跟应用内存使用情况基本应用篇如果通过自己编写的程序监控我将在以后的文章中阐述

　　线程因未知原因挂起比如死锁

　　程序死循环

　　本文将阐述如果编写程序对后两者故障实时跟踪并报告

　　首先我们需要一个单独的监控线程来监控需要监控的线程

　　我做了一个监控类 ThreadMonitor 在开始监控之前我们将监控线程的优先级设置为最高

　　 public ThreadMonitor() _MonitorThread = new Thread(new ThreadStart(MonitorTask)); _MonitorThread Priority = ThreadPriority Highest; _MonitorThread IsBackground = true;

　　接下来我们为这个线程提供几个公共方法

　　方法让调用者启动监控

　　方法用于将需要监控的线程注册到监控列表中

　　方法后面说明

　　/**//// /// Start monitor /// public void Start() _MonitorThread Start(); /**//// /// Monitor register /// /// Monitor parameter public void Register(MonitorParameter monitorPara) Debug Assert(monitorPara != null); Debug Assert(monitorPara Thread != null); if (GetTCB(monitorPara Thread) != null) throw new System ArgumentException( Register repeatedly! ); lock (_RegisterLock) _TCBTable Add(monitorPara Thread ManagedThreadId new TCB(monitorPara)); public void Heartbeat(Thread t) TCB tcb = GetTCB(t); if (tcb == null) throw new System ArgumentException( This thread was not registered! ); tcb LastHeartbeat = DateTime Now; tcb HitTimes = ; tcb Status &= ~ThreadStatus Hang;

　　下面让我来说说如何监控某个线程挂起

　　监控线程提供了一个心跳调用 Heartbeat 被监控的线程必须设置一个定时器定时向监控线程发送心跳如果监控线程在一定时间内无法收到这个心跳消息则认为被监控线程非正常挂起了这个时间又MonitorParameter参数的HangTimeout指定

　　光监控到线程挂起还不够我们必须要报告线程当前挂起的位置才有实际意义那么如何获得线程当前的调用位置呢？ Net framework 为我们提供了获取线程当前堆栈调用回溯的方法见下面代码

　　private string GetThreadStackTrace(Thread t) bool needFileInfo = NeedFileInfo; t Suspend(); StackTrace stack = new StackTrace(t needFileInfo); t Resume(); return stack ToString();

　　这里需要说明的是StackTrace(t needFileInfo) 必须在线程t Suspend后才能调用否则会发生异常但Thread Suspend 调用是比较危险的因为调用者无法知道线程t挂起前的运行状况可能线程t目前正在等待某个资源这时强制挂起非常容易造成程序死锁不过值得庆幸的是StackTrace(t needFileInfo)的调用不会和其他线程尤其是调用线程产生资源冲突但我们必须在这一句执行结束后迅速调用 t Resume 结束线程t的挂起状态

　　谈完了对线程非正常挂起的监控再谈谈对程序死循环的监控

　　在决定采用我现在的这个方案之前我曾经想通过 GetThreadTimes 这个API 函数得到被监控线程的实际CPU运行时间通过这个时间来计算其CPU占有率但很遗憾我的尝试失败了通过非当前线程下调用 GetThreadTimes 无法得到对应线程的CPU时间（好像非托管线程可以但 Net的托管线程我试了确实不行但原因我还没弄明白）另外GetThreadTimes 统计不够准确见对老赵写的简单性能计数器的修改续关于

　　所以没有办法我采用了一个不是很理想的方案

　　定时统计当前进程的TotalProcessorTime 来计算当前线程的CPU占有率如果这个CPU占有率在一段时间内大于 / (CPU 数）* % 则认为当前进程出现了死循环这个测试时间由 MonitorParameter参数的DeadCycleTimeout 属性指定

　　这就出现了一个问题我们只知道程序死循环了但不知道具体是那个线程死循环那么如何找到真正死循环的线程呢？

　　我采用的方法是每秒钟检测一次线程当前状态如果当前状态为运行状态则表示命中一次在确认出现死循环后我们在来检查在一个检查周期内的命中次数如果这个命中次数足够高则认为是该线程死循环了不过这样还是有问题主线程在等待windows 消息时或者控制台程序线程在等待控制台输入时该线程的状态居然始终是 Runing 其实是阻塞了但我没有找到一个很好的方法来得到线程当前处于阻塞状态怎么办？我想了个笨办法就是在上面两个条件都符合的情况下再看看在此期间有没有心跳如果没有心跳说明死循环了但如果有心跳也不一定就没有死循环遇到这种情况就将可疑的都全部报告了靠人来判断吧

　　我写了一个示例代码代码中有一个Winform 主线程和一个计数器线程计数器线程每秒记一次数并更新界面监控线程检查到非正常挂起或者死循环将在当前目录下写一个Report log 输出监控报告

　　点击Hang后主线程休眠秒计数器线程由于要更新界面也同样会被挂起

　　监控线程检查到两个线程挂起后报告如下

　　ThreadMonitorEventThread Name:Main threadThread Status:HangThread Stack: at System Threading Thread SleepInternal(Int millisecondsTimeout) at System Threading Thread Sleep(Int millisecondsTimeout) at DotNetDebug Form buttonHang_Click(Object sender EventArgs e) at System Windows Forms Control OnClick(EventArgs e) at System Windows Forms Button OnClick(EventArgs e) at System Windows Forms Button OnMouseUp(MouseEventArgs mevent) at System Windows Forms Control WmMouseUp(Message& m MouseButtons button Int clicks) at System Windows Forms Control WndProc(Message& m) at System Windows Forms ButtonBase WndProc(Message& m) at System Windows Forms Button WndProc(Message& m) at System Windows Forms Control ControlNativeWindow OnMessage(Message& m) at System Windows Forms Control ControlNativeWindow WndProc(Message& m) at System Windows Forms NativeWindow DebuggableCallback(IntPtr hWnd Int msg IntPtr wparam IntPtr lparam) at System Windows Forms UnsafeNativeMethods DispatchMessageW(MSG& msg) at System Windows Forms Application ComponentManager System Windows Forms UnsafeNativeMethods IMsoComponentManager FPushMessageLoop(Int dwComponentID Int reason Int pvLoopData) at System Windows Forms Application ThreadContext RunMessageLoopInner(Int reason ApplicationContext context) at System Windows Forms Application ThreadContext RunMessageLoop(Int reason ApplicationContext context) at System Windows Forms Application Run(Form mainForm) at DotNetDebug Program Main() at System AppDomain _nExecuteAssembly(Assembly assembly String[] args) at System AppDomain ExecuteAssembly(String assemblyFile Evidence assemblySecurity String[] args) at Microsoft VisualStudio HostingProcess HostProc RunUsersAssembly() at System Threading ThreadHelper ThreadStart_Context(Object state) at System Threading ExecutionContext Run(ExecutionContext executionContext ContextCallback callback Object state) at System Threading ThreadHelper ThreadStart()

　　 : : PMThreadMonitorEventThread Name:Counter threadThread Status:HangThread Stack: at System Threading WaitHandle WaitOneNative(SafeWaitHandle waitHandle UInt millisecondsTimeout Boolean hasThreadAffinity Boolean exitContext) at System Threading WaitHandle WaitOne(Int timeout Boolean exitContext) at System Threading WaitHandle WaitOne(Int millisecondsTimeout Boolean exitContext) at System Windows Forms Control WaitForWaitHandle(WaitHandle waitHandle) at System Windows Forms Control MarshaledInvoke(Control caller Delegate method Object[] args Boolean synchronous) at System Windows Forms Control Invoke(Delegate method Object[] args) at System Windows Forms Control Invoke(Delegate method) at DotNetDebug Form Counter() at System Threading ThreadHelper ThreadStart_Context(Object state) at System Threading ExecutionContext Run(ExecutionContext executionContext ContextCallback callback Object state) at System Threading ThreadHelper ThreadStart()

　　点击DeadCycle 按钮后让计数器线程死循环但主线程不死循环

　　监控线程检查到计数器线程死循环后报告如下

　　 : : PMThreadMonitorEventThread Name:Counter threadThread Status:HangThread Stack: at DotNetDebug Form DoDeadCycle() at DotNetDebug Form Counter() at System Threading ThreadHelper ThreadStart_Context(Object state) at System Threading ExecutionContext Run(ExecutionContext executionContext ContextCallback callback Object state) at System Threading ThreadHelper ThreadStart()

　　 : : PMThreadMonitorEventThread Name:Counter threadThread Status:Hang DeadCycleThread Stack: at DotNetDebug Form DoDeadCycle() at DotNetDebug Form Counter() at System Threading ThreadHelper ThreadStart_Context(Object state) at System Threading ExecutionContext Run(ExecutionContext executionContext ContextCallback callback Object state) at System Threading ThreadHelper ThreadStart()

　　下面是示例代码在

using System;using System Collections Generic;using System ComponentModel;using System Data;using System Drawing;using System Text;using System Windows Forms;using System Threading;using Sys Diagnostics;namespace DotNetDebug public partial class Form : Form Thread _CounterThread; ThreadMonitor _ThreadMonitor = new ThreadMonitor(); bool _DeadCycle = false; delegate void CounterDelegate(); private void DoDeadCycle() while (_DeadCycle) private void Counter() int count = ; while (true) DoDeadCycle(); labelCounter Invoke(new CounterDelegate(delegate() labelCounter Text = (count++) ToString(); )); _ThreadMonitor Heartbeat(Thread CurrentThread); Thread Sleep( ); public Form () InitializeComponent(); void OnThreadMonitorEvent(object sender ThreadMonitor ThreadMonitorEvent args) StringBuilder sb = new StringBuilder(); sb AppendLine(DateTime Now ToLongTimeString()); sb AppendLine( ThreadMonitorEvent ); sb AppendLine( Thread Name: + args Name); sb AppendLine( Thread Status: + args Status ToString()); sb AppendLine( Thread Stack: + args StackTrace); using (System IO FileStream fs = new System IO FileStream( report log System IO FileMode Append System IO FileAccess Write)) using (System IO StreamWriter sw = new System IO StreamWriter(fs)) sw WriteLine(sb ToString()); private void Form _Load(object sender EventArgs e) _ThreadMonitor ThradMonitorEventHandler += new EventHandler<ThreadMonitor ThreadMonitorEvent>(OnThreadMonitorEvent); _CounterThread = new Thread(new ThreadStart(Counter)); _CounterThread IsBackground = true; _ThreadMonitor Register(new ThreadMonitor MonitorParameter( Thread CurrentThread Main thread ThreadMonitor MonitorFlag MonitorHang | ThreadMonitor MonitorFlag MonitorDeadCycle)); _ThreadMonitor Register(new ThreadMonitor MonitorParameter( _CounterThread Counter thread ThreadMonitor MonitorFlag MonitorHang | ThreadMonitor MonitorFlag MonitorDeadCycle)); _CounterThread Start(); timerHeartbeat Interval = ; timerHeartbeat Enabled = true; _ThreadMonitor Start(); private void timerHeartBeat_Tick(object sender EventArgs e) _ThreadMonitor Heartbeat(Thread CurrentThread); private void ButtonDeadCycle_Click(object sender EventArgs e) _DeadCycle = true; private void buttonHang_Click(object sender EventArgs e) Thread Sleep( ); cha138/Article/program/net/201311/12301