Google doesn't use perforce anymore. They have a custom in-house SCM that has various interfaces wrapped around it. I'd recommend this video that describes it.
Piper is awesome, but it's not unreasonable to think of it as Perforce if you designed and built Perforce to scale to handling all of Google in one repo. It has basically the same set of nouns and verbs. citc is the really magical bit, UX wise, as it's like you had a Perforce view set up for our entire repo but never actually had to sync it manually. Just navigate to a file and start hacking.
The paper that corresponds to the talk includes numbers on that (I forget if they're in the video).
https://m.youtube.com/watch?v=W71BTkUbdqE