I had yet seen any benchmarks of reviews of such indication. Ruby 2.0 is a tiny steps in performance and GC. It would be nice if you could point me to some resources.
Sure. The biggest change is that it's moving from object marking to bitmap marking[1]. This makes it CoW-friendly, which should make forking far less painful (and much faster; copying all those memory pages takes time!). Bitmap marking can take advantage of parallel marking; Narihiro Nakamura (who did the new GC work for 2.0) has said in an interview[2] that as a result of parallel marking, he's managed to reduce GC time by 40% on dual-core machines, and the hint is that it may be possible to reduce it even further on machines with more cores.
I don't have benchmarks to share, but Nakamura is a very smart guy, and if he says he can get it, I have no reason to doubt it.
