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Re: About garbage collection


Well, I'm finally trying to remove the gc and see how the game perfroms.
But I have a problem doing so:
This code (taken from ArrayListIterator):

    next: func -> T {
        element := list get(index)
        index += 1
        return element

compiles to this:

this, uint8_t* __genericReturn41) {
    uint8_t* element =
    structs_ArrayList__ArrayList_get(this->list, element, this->index);
    this->index += 1;
    if (__genericReturn41) {
        lang_Memory__memcpy(__genericReturn41, element,

And I don't get it. I've also seen that a simple declaration like this:
compiles to this:
uint8_t* var =

Why is the allocation made?
Also, I have no chance to release this memory, right?


On Mon, Dec 20, 2010 at 10:08 AM, Damian Troncoso <damian.pop@xxxxxxxxx>wrote:

> Thanks,
> I will try the parallel mode on the boehm gc as soon as I have a little
> time and tell you about the results.
> I've read about the immix implementation of that guy before. He has not
> implemented defragmentation. Maybe that's the reason of the faster
> collection cycles. I don't think I want to implement a garbage collector by
> myself. At least not from scratch.
> My game is about using letters to make words. It uses a physics engine and
> the letters are into bubbles moving in the screen. That's why the collection
> lag is so noticeable.
> About rock, yes I've found some bugs that made me change my code to
> something else because rock just don't like some things. The biggest problem
> was founding where in my code the problem was. And the error reports are
> wrong most of the times.
> Are you planning on releasing rock 1.0? I thought it was abandoned or so
> and oc would have the attention now.
> Well, thanks a lot again!!
> Damian
> El 20/12/2010, a las 06:07, Amos Wenger < <ndd@xxxxxxxxxx><ndd@xxxxxxxxxx>
> ndd@xxxxxxxxxx> escribió:
> Hey there - just a quick response, hopefully followe by a more detailed one
> later but I'm on the clock here :)
> The Boehm GC does have a "parallel collection" mode, I have never tried it
> but it's documented here:
> <http://www.hpl.hp.com/personal/Hans_Boehm/gc/gcdescr.html><http://www.hpl.hp.com/personal/Hans_Boehm/gc/gcdescr.html><http://www.hpl.hp.com/personal/Hans_Boehm/gc/gcdescr.html>
> http://www.hpl.hp.com/personal/Hans_Boehm/gc/gcdescr.html
> (see "Mostly Parallel Garbage Collection")
> Apparently it can be enabled with '--enable-parallel-mark' at ./configure
> time, see:
> <http://www.hpl.hp.com/personal/Hans_Boehm/gc/simple_example.html><http://www.hpl.hp.com/personal/Hans_Boehm/gc/simple_example.html><http://www.hpl.hp.com/personal/Hans_Boehm/gc/simple_example.html>
> http://www.hpl.hp.com/personal/Hans_Boehm/gc/simple_example.html
> Also, if the Boehm GC appears to be not quite fast enough, you might
> consider another approach: <http://gamehaxe.com/tag/immix/><http://gamehaxe.com/tag/immix/><http://gamehaxe.com/tag/immix/>
> http://gamehaxe.com/tag/immix/
> This guy has implemented the IMMIX algorithm for garbage collection and it
> seems fast enough - also, he explains that he's triggering garbage
> collection
> once per frame - you might want to try that so you get shorter, less
> noticeable pauses.
> Also, what is your game about? :) Has anything annoyed you in rock lately?
> Are you looking forward to oc? Do you think rock should be released in 1.0?
> Amos
> ---- Original Message ----
> *From*: Damian < <damian.pop@xxxxxxxxx> <damian.pop@xxxxxxxxx>
> damian.pop@xxxxxxxxx>
> *To*: "Ooc dev" < <ooc-dev@xxxxxxxxxxxxxxxxxxx><ooc-dev@xxxxxxxxxxxxxxxxxxx>
> ooc-dev@xxxxxxxxxxxxxxxxxxx>
> *Sent*: Mon, Dec 20, 2010, 3:53 AM
> *Subject*: [Ooc-dev] About garbage collection
> Hi,
> this is not really a question about ooc, but I'm looking for some help,
> maybe someone can point me out something.
> I'm developing an iphone game in ooc, I'm really happy with what I have
> now, but I'm having a problem with garbage collection.
> I managed to configure and build Boehm GC for the iphone, and it works well
> but the collection cycle produces a freeze of about 120 miliseconds, and
> it's relly notorious and awful.
> I tried to configure it, but all I could achieve is having a collection
> cycle about every 10 seconds (instead of the 2 or 3 seconds I was having).
> I've read in ooc documentation about writing a custom sdk and do memory
> management, but I don't want to let to the garbage collection.
> Has anyone an idea of what can I do? Is there another way of garbage
> collection suitable for a game?
> I don't know if there is a garbage collection that does the collection in a
> background thread, I think boehm gc does not
> Well. Any help will be greatly appreciated.
> Thanks!
> Damian.