Implementation of "Scalable Event Handling for GHC"

[tsuraan]

I just read the article "Scalable Event Handling for GHC" by Sullivan
and Tibell, and I was wondering if its implementation has been
incorporated into the mainline GHC yet.  I'm sure the information is
out there, but I'm having a bit of trouble searching on it.  If it has
been integrated into mainline GHC, what version would I need to run to
try it out, and is there any documentation on what sort of things I
need to do to ensure that the new IO core is being used?