Possibility of non stop-the-world GC in the future?

[Nicholas Smith]

I'm interested in experimenting with game development in D, but 
the only thing putting me off is D's heavy GC reliance, which at 
the moment is a stop-the-world GC.

One of the biggest killers in game development is unreliable 
performance and before I tread down the D path I'm interested in 
knowing just what it is possible to do with the GC in D.

I'm not so knowledgable in the theory behind GCs but I know that 
in natively compiled languages your options are much more 
limited. I found CDGC as an apparently abandoned attempt at a 
concurrent GC (which also uses fork(), but the way Windows is 
going I'm caring less and less about them anyway).

So, how good can D's GC get?