I've been regularly reading on here for years now and this is the first time I've heard that the major bottle neck in Perl is that sub/methods calls are slow. It's common knowledge that Perl is significantly slower than straight C, but are you saying that the bulk of that slow down occurs due to sub/method calls being slow?
I've recently been poking around the perlguts, writing some XS/Inline code, and reading Perl's C source, so I'd love to get a peek at the underlying reasons for the slowdown you mention--even just a cursory peek which is probably all I could comprehend at this point.