Implementation of "Scalable Event Handling for GHC"

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?