> I started playing around with pool allocator for Ruby 1.9 for hashes.  
> cooked this up for an app that generates lots of Hashes.   > some performance improvements from tweaking constants inside gc.c for
> the app and using bsdmalloc[1], I still got a ~10% runtime reduction
> with this small change (for one particular app).

> Further testing and benchmarks results on different apps and comments
> would be greatly appreciated.

running it against the RBS might be interesting.
-rp