Hello,
Please review the fix for jdk10.
Bug: https://bugs.openjdk.java.net/browse/JDK-8185093
Webrev can be found at: http://cr.openjdk.java.net/~serb/8185093/webrev.00
jmh test: http://cr.openjdk.java.net/~serb/8185093/LocalGEproblem.java
While working on some other bug I found a performance issue in our
java2d pipeline in multi-threaded environment. We have a "hot spot" in
the "GraphicsEnvironment.getLocalGraphicsEnvironment()". This method is
executed every time the graphics object is created, for example
BufferedImage.java:
public Graphics2D createGraphics() {
GraphicsEnvironment env =
GraphicsEnvironment.getLocalGraphicsEnvironment();
return env.createGraphics(this);
}
So even if the application will draw to a different Images it will be
blocked for some time in this method.
I created a jmh test case which shows that implementing this method via
holder will speedup the next code:
Graphics2D graphics = bi.createGraphics();
graphics.drawLine(0, 0, 100, 100);
4 Threads:
- Before the fix: 8922 ops/ms
- After the fix : 9442 ops/ms
8 Threads:
- Before the fix: 4511 ops/ms
- After the fix : 11899 ops/ms
The main issue which I would like to clarify is it possible to remove
synchronize keyword from the getLocalGraphicsEnvironment(), possibly
with updating a specification? We have similar issues in other parts of
code which I would like to update later after this one.
--
Best regards, Sergey.
