GC leaks debugging

Tue Apr 5 09:02:00 GMT 2011

On 05/04/11 07:49, Erik Groeneveld wrote:
> [...]
>>> Any real program produces so much blacklist messages that it hardly
>>> runs. I'd like to investigate this or am I on the wrong track
>>> completely?
>>>> I think you are. The heap is small in this simple test case, so there
>> are no real problems.
>> I will ignore this for now then.
>>> You need to find out what the real problem is. Find just one of those
>> "need to allocate large block" messages, and find out why it is being
>> called. I suspect that there is an actual bug that is causing the
>> explosion and it can be found. Forget about 991 blacklist messages:
>> not useful.
>> I have done many tests, with different programs, which all run
> flawlessly on OpenJDK, but explode on GCJ. I have run some test last
> night, and I'll see from the logs that the heap is 1 GB, while about
> 700 MB of it is free.

That sounds like it's working perfectly, then. What is the problem?
> Also it seems that the finalization table keeps growing. I am
> running now, but later this day I'll post the log. (And search the
> mail archives with a new keyword: finalization ;-)

There is a known problem with finalization and weak references, but I
don't know the details. Maybe someone else can remeber.
>> I'd have a look myself, but there is no way to duplicate your problem.
>> BTW, is this on a 32-bit or 64-bit platform?
>> It is on 32-bit. On 64 bit, the blacklisting is not happening. But
> the heap keeps exploding, so you are right, the problem probably lies
> elsewhere.

OK, so you can concentrate on the 64-bit system, and forget about all
the blacklisting noise.
Andrew.