JP Morgan wrote a simple test program that loops and draws text using
the drawString() method which performed over 50 times slower with
JDK 1.2 (reference or production) on an Ultra 5 than the same java code
on the same machine with JDK 1.1x.

We've modified that program to perform a few different types of text
and other object drawing, and have seen performance to be from 6 to 267
times worse with DGA support, while a more consistent 88 to 150 times
worse without DGA support. (Under extreme cases, DGA performance regression
can range from 2x to 1000x worse than 1.1x)

The DGA performance appears to be some synchronization bug, in that
CPU is idle for most of the test, while the non-DGA performance appears
to be caused by a brute-force algorithm grabbing the entire frame and
putting the entire frame back regardless of how small a rectangle the
actual text occupies (can almost fully saturate 2 CPUs, and also makes
remote X display no longer an option).


Name: tb29552 Date: 03/13/99


There appears to be a very significant degradation in the redraw
performance when the Swing library is used instead of AWT when
the JVM is run on a remote machine over an LAN. The performance
of Swing approaches tolerable if the JVM is executing on the
same machine where the X server is running. The type of degradation
is where you can literally watch the different regions of the
window be repainted one after another.

To display this problem I have include two very small programs,
where one uses only AWT and the other is Swing-based. Run them
both first with the JVM on the local machine, and then remotely
log in to another machine nearby on a LAN and watch how terrible
a problem this is.

I know that the 1.2FCS release has a lot of performance problems
and it may be that this will get taken care of in the performance
tuning that is HOPEFULLY coming soon.

//~~~~~~~~~~~~~~~~~~~~~~~~ cut here ~~~~~~~~~~~~~~~~~~~~~~~~~~~
import java.awt.*;
import java.awt.event.*;

public class AwtPaintDemo {
    public static void main(String[] args) {
        Frame f = new Frame("AWT Paint Demo");
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
        f.add(new SimplePanel(), BorderLayout.CENTER);
        f.pack();
        f.show();
    }
}

class SimplePanel extends Canvas {

    public SimplePanel() {}

    public Dimension getPreferredSize() {
        return new Dimension(300,300);
    }

    public void paint(Graphics g) {
        super.paint(g);
        Dimension size = getSize();
        g.setColor(Color.red);
        g.fillOval(0,0,size.width, size.height);
    }
}


//~~~~~~~~~~~~~~~~~~~~~~~ cut here ~~~~~~~~~~~~~~~~~~~~~~~~~~
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class SwingPaintDemo {
    public static void main(String[] args) {
        JFrame f = new JFrame("Swing Paint Demo");
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
        f.getContentPane().add(new SimplePanel(), BorderLayout.CENTER);
        f.pack();
        f.setVisible(true);
    }
}

class SimplePanel extends JPanel {

    public SimplePanel() {
        super();
        setOpaque(false); // we don't paint all our bits
        setLayout(new BorderLayout());
    }

    public Dimension getPreferredSize() {
        return new Dimension(300,300);
    }

    protected void paintComponent(Graphics g) {
        super.paintComponent(g);

        Dimension size = getSize();
        g.setColor(Color.red);
        g.fillOval(0,0,size.width, size.height);
    }
}
======================================================================

Name: tb29552 Date: 03/19/99


Java app on Solaris 2.6 w/& JDK1.2 runs with instanteneous
screen refreshs when operating directly on the machine. When
running remote via X, the screen refresh is extremely slow,
you can see the screen being repainted in sections.
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