[nkurz]

On the other hand, having no cached result for the branch probably correlates strongly with not having the target in I-cache, which means you may be stalling out anyway. It also implies that the branch is not in the middle of a tight loop.

Regarding the size of the ROB, I was wondering about the size a while ago and found an interesting post from someone who measured it for modern Intel processors: Ivy Bridge (168), Sandy Bridge (168), Lynnfield (128), Northwood (126), Yorkfield (96), Palermo (72), and Coppermine (40). http://blog.stuffedcow.net/2013/05/measuring-rob-capacity/

I agree with you on the virtual part. I'm actually a C programmer more interested in how to implement efficient dispatch for interpreters. Eli (the original author) has some good posts on that as well: http://eli.thegreenplace.net/2012/07/12/computed-goto-for-ef...