RE: garbage collection take too much time to execute....

["Boehm, Hans" <hans dot boehm at hp dot com>]

Did you try with a recent version of gcj?

In the past, there have been problems with the collector looking for pointers in graphics memory.  You can try running the program with the GC_DUMP_REGULARLY environment variable set, and look at the size of the root sets.  If it appears to include your graphics memory, then that's probably the issue.

If not, GC_PRINT_STATS output might be helpful.

Hans

> -----Original Message-----
> From: java-owner@gcc.gnu.org [mailto:java-owner@gcc.gnu.org]
> On Behalf Of - -
> Sent: Tuesday, June 17, 2008 8:23 AM
> To: java@gcc.gnu.org
> Cc: decuplo@yahoo.com
> Subject: garbage collection take too much time to execute....
>
>
> Hi,
> I found a strange behaviour on code generated by gcj when
> compare its output with code generated by eclipse.
>
> Mainly the code generated by gcj  take too much time to
> perform a memory  garbage collection (about 5 seconds)
> instead of only 15 milliseconds of byte code generated by eclipse.
>
> The problem seems to happens when there are canvas and
> transform operations. I attach a simple snippet code that
> write a vertical text on canvas in order to reproduce the behaviour.
>
> The gcj compiler I use is:
> $ gcj --version
> gcj.exe (GCC) 3.4.5 (mingw-vista special r3) Copyright (C)
> 2004 Free Software Foundation, Inc.
> This is free software; see the source for copying conditions.
>  There is NO warranty; not even for MERCHANTABILITY or
> FITNESS FOR A PARTICULAR PURPOSE.
>
> with the swt version 3349:  "swt-gdip-win32-3349.dll"  and
> "swt-win32-3349.dll"
>
> I'm new of this discussion list, hoping not annoy you. It is
> a trouble or it is just a mistake on usage of transform?
> thanks you,
>
> x10
>
> Here is the code....
>
> -------------------------
> import org.eclipse.swt.layout.GridLayout;
> import org.eclipse.swt.graphics.Point;
> import org.eclipse.swt.widgets.Shell;
> import org.eclipse.swt.widgets.Display;
> import org.eclipse.swt.widgets.Button;
> import org.eclipse.swt.SWT;
> import org.eclipse.swt.widgets.Canvas;
> import org.eclipse.swt.layout.GridData;
> import org.eclipse.swt.graphics.GC;
> import org.eclipse.swt.graphics.Transform;
>
> public class snippet {
>
>         private Shell sShell = null;  //
> @jve:decl-index=0:visual-constraint="10,10"
>         private Button button = null;
>         private Canvas canvas = null;
>
>         /**
>          * This method initializes canvas
>          *
>          */
>         private void createCanvas() {
>                 GridData gridData = new GridData();
>                 gridData.horizontalAlignment =
> org.eclipse.swt.layout.GridData.FILL;
>                 gridData.grabExcessHorizontalSpace = true;
>                 gridData.grabExcessVerticalSpace = true;
>                 gridData.verticalAlignment =
> org.eclipse.swt.layout.GridData.FILL;
>                 canvas = new Canvas(sShell, SWT.BORDER);
>                 canvas.setLayoutData(gridData);
>                 canvas.addPaintListener(new
> org.eclipse.swt.events.PaintListener() {
>                         public void
> paintControl(org.eclipse.swt.events.PaintEvent e) {
>
> System.out.println("paintControl()"); // TODO Auto-generated
> Event stub paintControl()
>                                 GC gc = e.gc;
>
>                                 int xVertical = 200;
>                                 int yVertical = 200;
>                                 Transform t = new
> Transform(gc.getDevice());
>                                 t.translate(xVertical, yVertical);
>                                 t.rotate(-90f);
>                                 gc.setTransform(t);
>
>                                 gc.drawText("Vertical Text",0,0);
>
>                                 t.rotate(90f);
>                                 t.translate(-xVertical, -yVertical);
>                                 gc.setTransform(t);
>                                 t.dispose();
>
>                         }
>                 });
>         }
>
>         /**
>          * @param args
>          */
>         public static void main(String[] args) {
>                 // TODO Auto-generated method stub
>                 /* Before this is run, be sure to set up the
> launch configuration (Arguments->VM Arguments)
>                  * for the correct SWT library path in order
> to run with the SWT dlls.
>                  * The dlls are located in the SWT plugin jar.
>                  * For example, on Windows the Eclipse SWT
> 3.1 plugin jar is:
>                  *
> installation_directory\plugins\org.eclipse.swt.win32_3.1.0.jar
>                  */
>                 Display display = Display.getDefault();
>                 snippet thisClass = new snippet();
>                 thisClass.createSShell();
>                 thisClass.sShell.open();
>
>                 while (!thisClass.sShell.isDisposed()) {
>                         if (!display.readAndDispatch())
>                                 display.sleep();
>                 }
>                 display.dispose();
>         }
>
>         /**
>          * This method initializes sShell
>          */
>         private void createSShell() {
>                 GridData gridData1 = new GridData();
>                 gridData1.horizontalAlignment =
> org.eclipse.swt.layout.GridData.CENTER;
>                 sShell = new Shell();
>                 sShell.setText("Shell");
>                 sShell.setSize(new Point(579, 365));
>                 sShell.setLayout(new GridLayout());
>                 button = new Button(sShell, SWT.NONE);
>                 button.setText("Press me to redraw the canvas");
>                 button.setLayoutData(gridData1);
>                 button.addSelectionListener(new
> org.eclipse.swt.events.SelectionAdapter() {
>                         public void
> widgetSelected(org.eclipse.swt.events.SelectionEvent e) {
>
> System.out.println("widgetSelected()"); // TODO
> Auto-generated Event stub widgetSelected()
>
>                                 canvas.redraw();
>                                 System.err.println("start");
>                                 long before =
> System.currentTimeMillis();
>                                 System.gc();
>                                 long after =
> System.currentTimeMillis();
>                                 System.err.println("Elapsed
> milliseconds: " + (after-before));
>                                 System.err.println("end");
>                         }
>                 });
>                 createCanvas();
>         }
>
> }
> ----------------------------
>
>
>
>
>
>
>
>
>
>
> The java code attached is
>
>
>
>