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POcalling concurrently Graphics.Draw and new Bitmap from memory in thread take long time
 

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  1. POcalling concurrently Graphics.Draw and new Bitmap from memory in thread take long time
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    <p>Example1 <code> public partial class Form1 : Form {</p> <pre><code> public Form1() { InitializeComponent(); pro = new Thread(new ThreadStart(Producer)); con = new Thread(new ThreadStart(Consumer)); } private AutoResetEvent m_DataAvailableEvent = new AutoResetEvent(false); Queue&lt;Bitmap&gt; queue = new Queue&lt;Bitmap&gt;(); Thread pro; Thread con ; public void Producer() { MemoryStream[] ms = new MemoryStream[3]; for (int y = 0; y &lt; 3; y++) { StreamReader reader = new StreamReader("image"+(y+1)+".JPG"); BinaryReader breader = new BinaryReader(reader.BaseStream); byte[] buffer=new byte[reader.BaseStream.Length]; breader.Read(buffer,0,buffer.Length); ms[y] = new MemoryStream(buffer); } while (true) { for (int x = 0; x &lt; 3; x++) { Bitmap bmp = new Bitmap(ms[x]); queue.Enqueue(bmp); m_DataAvailableEvent.Set(); Thread.Sleep(6); } } } public void Consumer() { Graphics g= pictureBox1.CreateGraphics(); while (true) { m_DataAvailableEvent.WaitOne(); Bitmap bmp = queue.Dequeue(); if (bmp != null) { // Bitmap bmp = new Bitmap(ms); g.DrawImage(bmp,new Point(0,0)); bmp.Dispose(); } } } private void pictureBox1_Click(object sender, EventArgs e) { con.Start(); pro.Start(); } } </code></pre> <p></code> when Creating bitmap and Drawing to picture box are in seperate thread then Bitmap bmp = new Bitmap(ms[x]) take 45.591 millisecond and g.DrawImage(bmp,new Point(0,0)) take 41.430 milisecond </p> <p>when i make bitmap from memoryStream and draw it to picture box in one thread then Bitmap bmp = new Bitmap(ms[x]) take 29.619 and g.DrawImage(bmp,new Point(0,0)) take 35.540 the code is for Example 2 is </p> <p>why it take more time to draw and bitmap take time in seperate thread and how to reduce the time when processing in seperate thread. i am using ANTS performance profiler 4.3 <code> public Form1() {</p> <pre><code> InitializeComponent(); pro = new Thread(new ThreadStart(Producer)); con = new Thread(new ThreadStart(Consumer)); } private AutoResetEvent m_DataAvailableEvent = new AutoResetEvent(false); Queue&lt;MemoryStream&gt; queue = new Queue&lt;MemoryStream&gt;(); Thread pro; Thread con ; public void Producer() { MemoryStream[] ms = new MemoryStream[3]; for (int y = 0; y &lt; 3; y++) { StreamReader reader = new StreamReader("image"+(y+1)+".JPG"); BinaryReader breader = new BinaryReader(reader.BaseStream); byte[] buffer=new byte[reader.BaseStream.Length]; breader.Read(buffer,0,buffer.Length); ms[y] = new MemoryStream(buffer); } while (true) { for (int x = 0; x &lt; 3; x++) { // Bitmap bmp = new Bitmap(ms[x]); queue.Enqueue(ms[x]); m_DataAvailableEvent.Set(); Thread.Sleep(6); } } } public void Consumer() { Graphics g= pictureBox1.CreateGraphics(); while (true) { m_DataAvailableEvent.WaitOne(); //Bitmap bmp = queue.Dequeue(); MemoryStream ms= queue.Dequeue(); if (ms != null) { Bitmap bmp = new Bitmap(ms); g.DrawImage(bmp,new Point(0,0)); bmp.Dispose(); } } } private void pictureBox1_Click(object sender, EventArgs e) { con.Start(); pro.Start(); } </code></pre> <p></code></p>
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    1. USJuha Syrjälä
    1. USAbdul jalil
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    1. COIMHO, 3 images aren't enough to make judgement on performance. Difference in execution times here can be caused by multiple factors. I'd recommend you to make more measures. OFF TOPIC: The code you've wrote here is not well-parallelized: (1) you read ALL images before passing it to consumer - it's better to load and pass them one by one; (2) your implementation of Prod/Cons is broken which can be seen by the appearance of Thread.Sleep call. Rewrite it to using semaphores (see here http://en.wikipedia.org/wiki/Producer-consumer_problem). You also should dispose Graphics object you create.
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      1. POcalling concurrently Graphics.Draw and new Bitmap from memory in thread take long time
      1. USelder_george
 

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