gcj: mem leaks & speed.

[Rutger Ovidius]

Hi,

I have an app that runs well under java, but when compiled with gcj it
seems to leak memory (a gig in a few hours) -- this has been reported
by users of the app on linux and windows.

Are there any tools or methods I can use that would help me track down
the cause?  I'm finding it difficult since the mem leak isn't in my java
code as far as I can tell and java profiling isn't helping me.

(The app is an SWT gui app)

--

Also, while trying to track down memory use, I wrote the following
class:

public class Leak {
  public static void main(String[] argv) {
    long start = System.currentTimeMillis();
    for (int i = 0;; i++) {
      Leak l = new Leak(); 
      if (i % 100000000 == 0) {
        long curr = System.currentTimeMillis();
        System.out.println(i / 100000000 + ": " + (curr - start));
      }
    }
  }
}

This runs 10x as slow in gcj as it does in java on windows (~6x on
linux) If you remove the "Leak l = new Leak();" line, the speed
becomes rather similar to java. Why is class creation so slow? (or is
it GC cleanup that is slow?)

I then extended it to spawn threads to see if it gobbled up memory
(which it seems to..)

public class Leak implements Runnable {

  public static void main(String[] argv) {
   long start = System.currentTimeMillis();
   for (int i = 0;; i++) {
    Leak l = new Leak();
    new Thread(l).start();
      if (i % 10000 == 0) { // decrease
        long curr = System.currentTimeMillis();
        System.out.println(i / 10000 + ": " + (curr - start));
      }
    }
  }
  public void run() {
    int i = 9;
  }
}

This runs ~2x faster in gcj than in java for some reason (~5x faster
on linux). But, at the 16th line of output on windows:

libgcj failure: CreateEvent() failed
This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information.

I use: gcc version 3.4.0 20040130 (prerelease)

Regards,
Rutger Ovidius