CPU usage problem

Question

I have a network project, there is no timer in it. just a tcpclient that connect to a server and listen to receive any data from network.

         TcpClient _TcpClient = new TcpClient(_IpAddress, _Port);
        _ConnectThread = new Thread(new ThreadStart(ConnectToServer));
        _ConnectThread.IsBackground = true;
        _ConnectThread.Start();


    private void ConnectToServer()
    {
        try
        {
            NetworkStream _NetworkStream = _TcpClient.GetStream();
            byte[] _RecievedPack = new byte[1024 * 1000];
            string _Message = string.Empty;
            int _BytesRead;
            int _Length;

            while (_Flage)
            {
                _BytesRead = _NetworkStream.Read(_RecievedPack, 0, _RecievedPack.Length);
                _Length = BitConverter.ToInt32(_RecievedPack, 0);
                _Message = UTF8Encoding.UTF8.GetString(_RecievedPack, 4, _Length);

                if (_BytesRead != 0)
                {
                    //call a function to manage the data

                    _NetworkStream.Flush();
                }
            }
        }
        catch (Exception exp)
        {                
            // call a function to alarm that connection is false
        }
    }

But after a while the cpu usage of my application goes up(90%, 85%,...). even if no data receive.

could anybody give me some tips about cpu usage. I'm totally blank. i don't know i should check which part of the project!

Answer 1

could anybody give me some tips about cpu usage

You should consider checking the loops in the application, like while loop, if you are spend so much time waiting for some condition to became true, then it will take much CPU time. for instance

while (true)
{}

or

while (_Flag)
{
    //do something
}

If the code executed inside the while are synchronous, then the thread will be ending eating much of CPU cycles. to solve this problem you could executes the code inside the while in a different thread, so it will be asynchronous, and then use ManualResetEvent or AutoResetEvent to report back when operation executed, another thing to mentioned is to consider using System.Threading.Thread.Sleep method to till the thread to sleep and give the cpu time to execute other threads, example:

while(_Flag)
{
    //do something

    Thread.Sleep(100);//Blocks the current thread for 100 milliseconds
}

Answer 2

There are several issues with your code... the most important ones are IMHO:

• Use async methods (BeginRead etc.), not blocking methods, and don't create your own thread. Thread are "expensive>" resources - and using blocking calls in threads is therefore a waste of resources. Using async calls lets the operating system call you back when an event (data received for instance) occured, so that no separate thread is needed (the callback runs with a pooled thread).
• Be aware that Read may return just a few bytes, it doesn't have to fill the _ReceivedPackbuffer. Theoretically, it may just receive one or two bytes - not even enough for your call to ToInt32!