Manually triggering garbage collection

Manually triggering garbage collection

[Jean Krivine]

Dear list,

I am running a memory intensive stochastic simulator written in ocaml.
After initialization of the data structure (which eats up a lot of
memory but that's normal) I observe a memory leak during the
simulation which should not be there.
I noticed that if I run Gc.major() every n computation events after
initialization (I can make n vary), then there is no more memory leak
(the memory the process is using is constant).

So my question is the following:
Is there a rational way to detect I should call for Gc.Major()? (for
the moment I am triggering it every n events which is arbitrary)

Thank you very much

Jean

Re: [Caml-list] Manually triggering garbage collection

[Jean Krivine]

OK great I' ll try,
For the moment I just set a Gc alarm that detects whether memory usage
is above a certain limit and if so, sets the overhead to 0, which
stops completely the memory "leak".
Do you think that would improve to increase the size of the major heap?
Also, do you know how often the alarm is tested? is it each time a
major collection is performed?

Thanks a lot
J

On Tue, Jul 29, 2008 at 8:53 AM, Damien Doligez <damien.doligez@inria.fr> wrote:
> Hello Jean,
>
> On 2008-07-26, at 21:15, Jean Krivine wrote:
>
>> I am running a memory intensive stochastic simulator written in ocaml.
>> After initialization of the data structure (which eats up a lot of
>> memory but that's normal) I observe a memory leak during the
>> simulation which should not be there.
>> I noticed that if I run Gc.major() every n computation events after
>> initialization (I can make n vary), then there is no more memory leak
>> (the memory the process is using is constant).
>>
>> So my question is the following:
>> Is there a rational way to detect I should call for Gc.Major()? (for
>> the moment I am triggering it every n events which is arbitrary)
>
>
> This might be a fragmentation problem, but if calling Gc.major()
> fixes it, I guess it's not a true leak (i.e. the memory would stabilize
> at some point).
>
> At any rate, you might want to try the CVS head version (3.11+dev):
> it uses first-fit allocation in order to fight fragmentation, and I'd
> like to know how well it does in the wild.
>
> -- Damien
>
>