Posted by Matteo Battaglio on Jul 14, 2010; 4:28pm
URL: https://forum.jogamp.org/Texture-rendering-performance-problems-tp966089p966977.html

Thanks for the sudden responses!

Okay, I made some tests and discovered that the problem is much simpler but maybe more worrying:

I wrote a simple test app which has a main method that: creates a JFrame, adds a GLJPanel to it, and then runs the following cycle:

while (true) {
    try {
        Thread.sleep(40); //25 times/second
        glPanel.repaint();
    }
    catch (InterruptedException ex) {}
}

The concrete class of the GLJPanel implements the interface GLEventListener and leaves all the implemented methods empty, except for the display which calculates the average frequency of calls to it; so I don't call any openGL command at all.

To my surprise, the test showed that the CPU load has a 1:1 relationship with the size of the panel, until it reaches a value of 50%: once at 50%, the cpu load remains constant, but as I increase the size of the panel, the rate of the calls to the display method continues to decrease (while the rate of repaint() calls is still 25)!

This makes me wonder that the CPU load can't increase above the limit of 50% on my PC: this makes sense to me because my CPU is a dual core, and awt/swing use a single thread to render the scene, so it can't take advantage of the two cores.

But my big question is why it exploits such a high CPU usage although it isn't doing nothing?
Can anyone reproduce this issue?

(I could also send my source code if anyone needs it)

Many thanks in advance!