out of memory problems with kaffe

Eric S Fraga ucecesf at ucl.ac.uk
Thu Mar 5 09:09:40 PST 1998


In my ongoing battles to reduce computational times for a large
application, I've again tried kaffe [it should be said that before I moved
to Java 1.1.x, I always used kaffe and was very happy with it -- since
moving to 1.1, kaffe has not been competitive with the JDK].  I'm now
trying kaffe 0.9.2 on Linux 2.0.27, Red Hat 4.2.

Anyway, I try to use kaffe for a particular problem and it always quits
prematurely, saying that it has run out of memory (this doesn't happen
when I use the JDK, versions 1.1.1 through 1.1.5). Running with
-verbosemem set, I get the following diagnostics just before it quits: 

 <GC: heap 17408K, total 14446K, alloc 0K, marked 1645K, freeing 12800K>

Memory statistics:
     object: Nr   3103  Mem     91K            array: Nr   2627  Mem 343K
      class: Nr    244  Mem     28K           method: Nr    224  Mem 145K
      field: Nr    157  Mem     24K           static: Nr     95  Mem 3K
   dispatch: Nr    226  Mem     81K         bytecode: Nr   1899  Mem 137K
  exception: Nr    199  Mem      7K         constant: Nr    224  Mem 200K
  utf8const: Nr 232131  Mem  12305K        interface: Nr     67  Mem 0K
       root: Nr      0  Mem      0K     indirectRoot: Nr     14  Mem 0K
        jit: Nr    516  Mem    416K            fixed: Nr     75  Mem 498K
       lock: Nr     35  Mem      1K            other: Nr   1397  Mem 158K

I'm particularly concerned about the utf8const term. I do use a lot of
strings but almost none of them are kept for long term (i.e. they are
almost always local scratch variables).  All the other memory entries seem

The garbage collection message at the top is similar to the messages that
precede my program terminating early.  It always seems to imply that it's
freeing app. 13MB yet never seems to free them. 

Can anybody suggest anything that might help?  I have tried the -mx option
but this has no effect at all. The -ss option doesn't work: kaffe just
hangs!  My system has 64 MB of RAM (plus a _lot_ of swap) which should be
more than sufficient for my problem.


Eric S Fraga, University College London, www.chemeng.ucl.ac.uk/staff/fraga.html

More information about the kaffe mailing list