Hi.

>  "the Ruby core team is working on their own solution for a better GC and it
> should be available soon. (Ruby 1.9.x)"

This topic may be connected with me.

I making bitmap marking gc.
This is same approach of REE(RubyEnterpriseEdition) GC.
However, the different point is search technique of the bitmap position.

The REE bitmap position search is a linear search[O(n)].
But ruby 1.9.x heap slot fix 16KB. Thus, heaps contain many heap slot.
Search time of the BitMap position becomes the problem more.

I made a bitmap position search by the alignment technique.[O(1)].
This method is not relate to number of heap slot.

This patch url is
http://github.com/authorNari/ruby/tree/master/patch/gc_bitmap_by_align_to_v_1_9_0_4.patch
# This is incomplete. The reason is because SEGV occurs in make test :)

Regards
-- 
Narihiro Nakamura