From: Marcin Raczkowski <mailing.mr@...>
Date: 2008-01-11T15:56:05+09:00
Subject: Re: Manual Memory Management

Kurt Stephens wrote:
> Marcin Raczkowski wrote:
>> Kurt Stephens:
>> I actually did some tests with naive implementation of Boehem, mayby
>> I'll be able to help.
>>
> 
> How far did you get?
> 
Not very far really I'm afraid, I choose subset of Ruby, and started 
testing how would it work if I exchange some calls in ruby GC code - I 
think that aproach was wrong now, and hacking it would require more 
complex knowlage and planing.

>> Problem with copying collectors is that they make pages dirty really
>> quick - so you loose COW advantage (that happens with curent mark-sweep
>> implementation to see
>> http://izumi.plan99.net/blog/index.php/category/ruby/)
> 
> Any allocator that uses next/prev pointers in allocation headers will
> cause dirty pages as soon as objects are moved to free lists. Since ruby
> uses mailoc() underneath this is pretty much guaranteed. :)

Izumi tried to change this he also provided some good guides in english 
for ruby GC.

> 
>> About reference counting collectors - It was an idea - I guess
>> implementation would have to be really good - advantage of ruby is that
>> you won't segfault ;)
>>
>>
> 
> Reference counting will require major changes to all extensions and
> internals.  Rather than added ref count dec/inc operations, we might
> want to invest that effort crafting a good write barrier and do
> generational GC.

Sure, as i said it was an idea, I have finals comming soon, but I'm 
willing to help when they finish.

greets
Marcin Raczkowski