生产者/消费者通过Queue获取不同的数据

Question

解决了！！！ 谢谢

小心放入Queue的对象的类型。如果您输入一个值（例如int），则入队将进行复制，每个人都很高兴。 如果您放置一个引用（例如byte []，string），将其放入队列，那么就会出现问题。 如果在使用者读取该引用之前对其进行了更改 ，那么使用者将读取更改后的数据版本。

为避免此问题，请在入队后立即在rxThread中获取新版本的帧引用 。 码：

public void rxThreadFunc()
        {
         byte[] data = new byte[datalen];//declare for the first iteration.
            int j = 0;
            while (true)
            {

                for (int i = 0; i < rxlen; i++)
                {
                    data[j] = (byte)i;
                    j++;
                    if (j >= datalen)
                    {
                        j = 0;
                        mQ.Add(data);
                        using (StreamWriter fwriter = new StreamWriter("C:\\testsave\\rxdata", true))
                        {
                            for (int k = 0; k < datalen; k++)
                            {
                                fwriter.Write(data[k]);
                                fwriter.Write(",");
                            }
                            fwriter.Write("\n");
                        }
                     data = new byte[datalen];//create new reference after enqueue/Add
                    }
                }

            }
        }//rxThreadFunc()

Update1我刚刚编写了另一个简单的代码，因此每个人都可以在没有串行端口硬件的情况下对其进行测试。 单击按钮运行程序。 我认为线程优先级会导致此问题，而无需更改rxthread的线程优先级，则dataProc线程将获取正确的数据。 但我仍然不知道为什么。

rxThread.Priority = ThreadPriority.Hightest

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Collections.Concurrent;
using System.Threading;
using System.IO;
namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();

        }

        private void button1_Click(object sender, EventArgs e)
        {
            Thread rxThread = new Thread(rxThreadFunc);
            rxThread.Priority = ThreadPriority.Highest;//this causes problem
            rxThread.Start();
            Thread procThread = new Thread(dataProc);
            procThread.Start();
        }
        BlockingCollection<byte[]> mQ = new BlockingCollection<byte[]>();
        int datalen = 30;         
        int rxlen = 200;
        public void rxThreadFunc()
        {
            int j = 0;
            while (true)
            {
               byte[] data = new byte[datalen];//is this in the right place?
                for (int i = 0; i < rxlen; i++)
                {
                    data[j] = (byte)i;
                    j++;
                    if (j >= datalen)
                    {
                        j = 0;
                        mQ.Add(data);
                        using (StreamWriter fwriter = new StreamWriter("C:\\testsave\\rxdata", true))
                        {
                            for (int k = 0; k < datalen; k++)
                            {
                                fwriter.Write(data[k]);
                                fwriter.Write(",");
                            }
                            fwriter.Write("\n");
                        }
                    }
                }

            }
        }//rxThreadFunc()
        public void dataProc()
        {
            byte[] outData = new byte[datalen];
            while (true)
            {
                if (mQ.Count > 1)
                {
                    outData=mQ.Take();
                    using(StreamWriter fwriter=new StreamWriter("C:\\testsave\\dataProc",true))
                    {
                        for (int i = 0; i < datalen; i++)
                        {
                            fwriter.Write(outData[i]);
                            fwriter.Write(",");
                        }
                        fwriter.Write("\n");
                    }
                }
            }
        }

    }
}

---

---

说明：我编写了这个包含两个线程的应用程序。 RxThread从串行端口接收数据，按标题标记0x55 0xaa对其进行排序，将以下30个字节放入FrameStruct类中，然后将该FrameStruct放入Queue中。 dataProcess线程从Queue获取帧，然后将其存储到磁盘。

的SerialPort =（RXBUFF）=> RxThread =（rxFrame，队列）=> dataProcess ==>磁盘

问题：由dataProcess线程接收并保存到磁盘的数据以某种方式损坏。

尝试：这是我尝试供您参考的内容。

1. 我尝试了BlockedCollection，它自然是线程安全的，而不是Queue，它仍然无法正常工作。 所以我想这不是Queue的问题。
2. 我试图在FrameStruct中添加另一个成员int cnt，它在RxThread中的messageQ.Enqueue（）之前自动增加。 然后dataProcess线程可以正确获取它。 所以我认为可能是data []有问题，但是...
3. 但是我尝试将字节数据[30]而不是FrameStruct放入Queue中，无法正常工作。

4. 我也认为dataProcess收到的时间也是正确的。

   5.如果我在RxThread的Monitor.Pulse（）之后放置Thread.sleep（20），问题就解决了，但我不明白为什么？ 如果我换到另一台电脑怎么办？

这是代码快照。

//declared:
//Queue<FrameStruct>messageQ=new Queue<FrameStruct>;
//object _LockerMQ=new object();
private void RxThread()
    {
        int bytestoread, i;
        bool f55 = false;//55 flag
        bool fs = false;//frame start flag
        int j=0;//data index in FrameStruct
        int m_lMaxFram=32;
        bytestoread = 0;
        FrameStruct rxFrame = new FrameStruct((int)m_lMaxFrame);
        while (true)
        {
            if (Serial_Port.IsOpen == true)
            {
                if ((bytestoread = Serial_Port.BytesToRead) > m_lMaxFrame*2)//get at least two frames
                {
                        rxbuff = new byte[bytestoread];  
                        Serial_Port.Read(rxbuff, 0, bytestoread);
                        for (i = 0; i < bytestoread; i++)
                        {
                            if (rxbuff[i] == 0x55)
                            {
                                f55 = true;
                                continue;
                            }
                            if (rxbuff[i] == 0xaa && f55)
                            {//frame header 0x55, 0xaa
                                //new frame start
                                fs = true;
                                f55 = false;
                                j = 0;//rxframe index;
                                rxFrame.time = DateTime.Now;//store the datetime when this thread gets this frame
                                continue;
                            }
                            if (fs && j < m_lMaxFrame - 2)
                            {//frame started but not ended
                                rxFrame.data[j] = rxbuff[i];
                                j++;
                            }
                            if (j >= (m_lMaxFrame - 2) && fs)
                            {//frame ended if j=30, reaches the end of rxFrame.data
                                fs = false;
                                lock(_LockerMQ)
                                {
                                    messageQ.Enqueue(rxFrame);
                                Monitor.Pulse(_LockerMQ);
                                }
                                 //Thread.Sleep(20);//if uncomment this sleep, problem solved
                              using (StreamWriter fWriter = new StreamWriter("c:\\testsave\\RXdata", true))//save rxThread result into a file rawdata
                    {
                        fWriter.Write(rxFrame.time.ToString("yyyy/MM/dd HH:mm:ss.fff"));
                        fWriter.Write(",");
                        for (int k = 0; k < m_lMaxFrame - 2; k++)
                        {
                            fWriter.Write(rxFrame.data[k]);
                            fWriter.Write(",");
                        }
                        fWriter.Write("\n");
                    }
                            }
                           }
                }//if ((bytestoread=Serial_Port.BytesToRead) > 0)
                rxbuff = null;
                Thread.Sleep(20);
            }//(Serial_Port.IsOpen==true)
            Thread.Sleep(100);
        }//while(true),RxThread sleep
    }//private void RxThread()

DataProcess线程：

 public void dataProcess()
    {
      while (true)
        {
            lock (_LockerMQ)
            {
                while (messageQ.Count < 1) Monitor.Wait(_LockerMQ);//get at least one frame data
                f_NewFrame = messageQ.Count;
                if (f_NewFrame > 0)
                {
                    procFrame = messageQ.Dequeue();
                    using (StreamWriter fWriter = new StreamWriter("c:\\testsave\\dPdata", true))
                    {
                        fWriter.Write(procFrame.time.ToString("yyyy/MM/dd HH:mm:ss.fff"));
                        fWriter.Write(",");
                        for (int i = 0; i < m_lMaxFrame - 2; i++)
                        {
                            fWriter.Write(procFrame.data[i]);
                            fWriter.Write(",");
                        }
                        fWriter.Write("\n");
                    }
                }//if(f_NewFrame>0)

            }//lock(messageQ)
  }
}

FrameStruct包含时间成员和数据[30]

class FrameStruct
{
        public FrameStruct(int m_lMaxFrame)
        {
            time = DateTime.Now;
            data = new byte[m_lMaxFrame - 2];
        }
        public DateTime time;
        public volatile byte[] data;//volatile doesn't help
}

RxThread保存的rxData是正确的，显示：

2015/07/18 18:40:26.125,127,255,255,255,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,111,51,204,
2015/07/18 18:40:26.177,128,0,255,255,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,112,51,204,
2015/07/18 18:40:26.177,128,0,255,255,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,113,51,204,
2015/07/18 18:40:26.297,127,255,255,255,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,114,51,204,
2015/07/18 18:40:26.298,127,255,255,255,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,115,51,204,
2015/07/18 18:40:26.298,127,255,255,255,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,116,51,204,
2015/07/18 18:40:26.299,127,255,255,255,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,117,51,204,
2015/07/18 18:40:26.420,127,255,255,255,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,118,51,204,
                                                                                     //^this columns is accumulated number

dataProcessThread保存的dPdata是WRONG，显示：

2015/07/18 18:40:31.904,127,255,255,255,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,227,51,204,
2015/07/18 18:40:31.905,127,255,255,255,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,228,51,204,
2015/07/18 18:40:31.905,127,255,255,255,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,229,51,204,
2015/07/18 18:40:32.026,128,0,255,255,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,231,51,204,
2015/07/18 18:40:32.026,128,0,255,255,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,231,51,204,
2015/07/18 18:40:32.147,128,0,255,255,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,232,51,204,
2015/07/18 18:40:32.148,128,0,255,255,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,233,51,204,
2015/07/18 18:40:32.148,128,0,255,255,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,234,51,204,
2015/07/18 18:40:32.269,128,0,255,255,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,236,51,204,
2015/07/18 18:40:32.269,128,0,255,255,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,236,51,204,
2015/07/18 18:40:32.510,128,0,255,255,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,237,51,204,
2015/07/18 18:40:32.512,128,0,255,255,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,240,51,204,
2015/07/18 18:40:32.512,128,0,255,255,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,240,51,204,
2015/07/18 18:40:32.514,127,255,255,255,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,240,51,204,
2015/07/18 18:40:32.514,127,255,255,255,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,241,51,204,
2015/07/18 18:40:32.635,128,0,255,255,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,243,51,204,
2015/07/18 18:40:32.635,128,0,255,255,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,243,51,204,
                                                                                   //^this accumulated number is not correct

请帮忙！

谢谢！

Answer 1

FrameStruct是一个类（而不是结构），排队时，您一次又一次使用相同的引用。

Answer 2

更新2

这是基本的生产者使用者，只需添加您的逻辑即可：

class Program
{

    static BlockingCollection<int> mQ = new BlockingCollection<int>();

    static void Main(string[] args)
    {

        Thread rxThread = new Thread(rxThreadFunc);
        rxThread.Priority = ThreadPriority.Highest;//this causes problem
        rxThread.Start();
        Thread procThread = new Thread(dataProc);
        procThread.Start();
        Console.ReadLine();
    }


    static public void rxThreadFunc()
    {
        for (int i = 0; i < 10; i++)
        {
            mQ.Add(i);
        }
    }


    static public void dataProc()
    {
        foreach (int outData in mQ.GetConsumingEnumerable())
        {
            Console.WriteLine(outData);
        }
    }


}

回答更新1：

• 是的，这是正确的地方

现在，由于使用了BlockingCollection，使用者（dataProc）可能非常简单（只需删除循环和计数检查，它将为您完成所有这些同步操作）：

 foreach (byte[] outData in _taskQ.GetConsumingEnumerable())
 {
     using(StreamWriter fwriter=new StreamWriter("C:\\testsave\\dataProc",true))
                {
                    for (int i = 0; i < datalen; i++)
                    {
                        fwriter.Write(outData[i]);
                        fwriter.Write(",");
                    }
                    fwriter.Write("\n");
                }
 }

现在，问题可能与原始帖子中的有所不同。 也许是因为生产者在这里也将数据写入文件？

原版的：

它有很多解释，但是解决方案很简单，只需将FrameStruct的初始化添加到第二个“ if”语句中：

rxFrame = new FrameStruct((int)m_lMaxFrame);

如保存的数据文件中所示：在损坏的文件中，每当您缺少值（例如230）时，您就会重复其他值（例如231）。 缺失值的计数等于重复值的计数。

这样做的原因是您将对同一对象实例的引用添加到队列中。 让我们看一下以下情况：RxThread循环N次，在上下文切换到dataProcess线程之前，它将N个引用添加到队列的同一FrameStruct实例。 在这种情况下，数据将是上下文切换之前最后一次读取循环迭代中的数据。 现在发生了上下文切换：dataProcess在上下文切换回RxThread之前循环M <N次，因此它从队列中读取M个元素，但所有元素都指向同一实例，因此它将M行同一行写入M元素。文件（如前所述）

现在，为什么Thread.Sleep有帮助。 简短的答案：每次RxThread将1个元素添加到队列中时，上下文切换到dataProcess线程的可能性都很高。 所以它实际上是：读一个->上下文切换->写一个...然后再次做同样的事情。

长答案是：dataProcess线程执行Monitor.Wait之后，它进入等待队列，上下文切换调度RxThread。 现在，线程将第一个元素添加到队列中，然后执行Monitor.Pulse。 这会将dataProcess线程移至就绪队列。 但不必安排立即运行，因此RxThread可以进行另一次迭代。 但是，如果您执行Thread.Sleep-现在很有可能会安排上下文切换和ataProcess线程。