Screensaver application 100% CPU usage

[wushupork]

I have written a screensaver application in C# .NET and have noticed
that whenever the animation loop is running - CPU usage always spikes
up close to 100%. My application uses a paint thread which is set at
100ms.

the program looks sort of like this:

// constructor
public Form1()
{
InitializeCompo nent();

// initialization code

tmrPaintRefresh =new System.Timers.T imer(100);
tmrPaintRefresh .Elapsed+=new
System.Timers.E lapsedEventHand ler(tmrPaintRef resh_Elapsed);

}
private void tmrPaintRefresh _Elapsed(object sender,
System.Timers.E lapsedEventArgs e)
{
// update animation variables

Invalidate();
}

protected override void OnPaint(PaintEv entArgs e)
{
// contains only code to draw objects on the screen
}
The program works fine and everything looks as it should but CPU usage
is abnormally high.

my question is: where should I be calling Application.DoE vents();?

how can I restructure it so that it is not so CPU intensive. All it is
doing is animating text on the screen; it should not be such a CPU
hog.

Thanks much,

wushupork

[Greg Ewing [MVP]]

wushupork, just to test things out, try putting a thread.Sleep(10 0) after
Invalidate() and see if that changes your CPU issue.

--
Greg Ewing [MVP]
http://www.citidc.com
"wushupork" <wu*******@gmai l.com> wrote in message
news:ff******** *************** ***@posting.goo gle.com...

I have written a screensaver application in C# .NET and have noticed
that whenever the animation loop is running - CPU usage always spikes
up close to 100%. My application uses a paint thread which is set at
100ms.

the program looks sort of like this:

// constructor
public Form1()
{
InitializeCompo nent();

// initialization code

tmrPaintRefresh =new System.Timers.T imer(100);
tmrPaintRefresh .Elapsed+=new
System.Timers.E lapsedEventHand ler(tmrPaintRef resh_Elapsed);

}
private void tmrPaintRefresh _Elapsed(object sender,
System.Timers.E lapsedEventArgs e)
{
// update animation variables

Invalidate();
}

protected override void OnPaint(PaintEv entArgs e)
{
// contains only code to draw objects on the screen
}
The program works fine and everything looks as it should but CPU usage
is abnormally high.

my question is: where should I be calling Application.DoE vents();?

how can I restructure it so that it is not so CPU intensive. All it is
doing is animating text on the screen; it should not be such a CPU
hog.

Thanks much,

wushupork

[wushupork]

Thanks Greg,

That seemed to have solved my problem. On a related note, I have a
system tray app that communicates with the screensaver. All it does is
listens for a message on a port from the screensaver using a
TcpListener.

How do I write a simple socket app so that it does not do a busy wait.

Right now my app looks like this

// event handler for form load
private void Form1_Load(obje ct sender, System.EventArg s e)
{
thread1 = new Thread(new ThreadStart(Lis ten));
thread1.IsBackg round = true;
}

private void Listen()
{
Socket socketForClient ;
//TcpListener is listening on the given port...
TcpListener tcpListener = new TcpListener(SCR EENSAVER_PORT);

try
{
tcpListener.Sta rt();

while (blnListening)
{

if (tcpListener.Pe nding())
{
//Accepts a new connection...
socketForClient = tcpListener.Acc eptSocket();

if (socketForClien t.Connected)
{
// do my stuff
}

socketForClient .Close();
}

// newly added sleep to free up some CPU
Thread.Sleep(10 0);

}
}
catch(Exception e)
{
Console.WriteLi ne(e.ToString() ) ;
}
finally
{
tcpListener.Sto p();
}

// end of code

since adding the Thread.Sleep(10 0) here, the CPU isn't so busy, but I
am getting the feeling that it is still doing a busy wait. What should
I be doing?

thanks,

wushupork