Rails on Ruby 1.9

I am curious: how soon shall we espect to have a Ruby on Rails version
benefitting from ruby 1.9?

It depends on the confluence of several semi-independent streams.

First, the rails-core team seems to have one person working on 1.9
compatibility.

Second, ruby1.9 itself needs to stabilize a bit before it's ready for
serious production work. Matz's team switched the version number from
the hoped for 1.9.1 to 1.9.0 shortly before the Christmas release and
indicated that 1.9 shouldn't be considered stable. It will probably
be a few more months before they release a 1.9.1 version which would
be the first 'stable' release. Until then any 1.9 stuff rails or not
should probably be considered experimental.

And then there's the question of 1.9 compatibility changes to all the
third-party plugins and gems which are used in the many rails
applications.

It's all coming, no doubt, but just when is hard to predict.

Thank you for answering.
I was eager to know cause I've read wonders about 1.9 performances and
was wondering how that would impact on my rails app performance...