Hmm, I think that ought to be pretty doable with the callgrind output actually. I'm using amd64 rather than a modern ISA, so the calls do necessarily touch "m

Hmm, I think that ought to be pretty doable with the callgrind output actually. I'm using amd64 rather than a modern ISA, so the calls do necessarily touch "memory", but leaf functions are still especially cheap—they can use temporary registers for local variables. In the case of Emacs most of the functions are compiled Lisp, and I doubt the Lisp compiler is smart enough to exploit leafness in its register allocator.