Re: [Caml-list] GC question.

[Damien Doligez <damien.doligez@inria.fr>]

On Oct 25, 2005, at 21:20, MATTHEW HAMMER wrote:

> I'm not certain what style of garbage collection is done in the ocaml
> runtime environment,

Generational with two generations, and incremental for the old
generation.

> but if its generational for example, I'd like to
> move certain values into the 'oldest' generation, so that the garbage
> collector doesn't waste time on them.

The only way to do that is to call Gc.minor, but it won't save any time.

> The running program in question has a large datastructure that is very
> persistent which takes a lot of GC time if it is transversed too
> often.

If it's large, it's going to be in the major heap anyway.  If you
don't want the GC to traverse it, you'll have to put it outside the
heap, but it might will require a lot of work.  For example, bigarrays
are outside the heap.  Or you could write some C code to build your
structure out of malloc blocks, but I'd count that as a desperate
measure.

> So I suppose what I'm asking is: is there a way to give the GC'er
> 'hints' through the Obj module, or any other method?

You can control some parameters with the Gc module, but there's
no way to give hints about a specific piece of data.

-- Damien