configuration: 945GM laptop, X.Org X Server 126.96.36.1991 and xf86-video-intel-2.3-rc2:
All applications using Java2D become extremly slow when EXA is enabled.
A good example is Java2D where many benchmarks scored 700fps with XAA, but now only with a few FPS. Furthermore the whole UI becomes very unresponsive.
1.) Start Java2Demo:
java -jar /usr/java/jdk1.6.0_10/demo/jfc/Java2D/Java2Demo.jar (make sure to have an official java version, not classpath, gij, icedtea or whatever)
2.) Click on the "Lines"-Tab
3.) Double-Click on the rotating arrow (maximizes them)
4.) set anim-delay to zero (slider on the right)
5.) enable/disable antialising (without antialiasing this is opaque, simple X11 core rendering).
This is just a single example where the intel/exa driver performs very poor, but also simple 2D applications that consist only of a few buttons become sluggish.
Could you do some profile to see what slow things down?
The machine died on Tuesday and won't be available for testing for several weeks.
However it should be fairly easy to repeat the suggested steps (on a GMA950), and you should be able to see the reported slowdowns, which lead in this cause to an almost unresponsive application.
Mark as dup with EXA performance bug in case java 2d has no specific other issues.
*** This bug has been marked as a duplicate of bug 13389 ***
Java2D relies a lot on readbacks, because it provides a lot advanced features but restricts (for now) itself only to X11-Core drawing.
Therefor I don't think those two bugs are duplicates, this one is specific to Java2D, the other reports general slowness.
Clemens, feel free to ping me if you ever see X on your profiles or is limiting your performance.