After a few websearches, it seems as if you can use:

(void)(*CvXSUB(cv))(cv);
[download]

to skip the overhead of perl_call_sv() and call the internal C code directly. Supposedly, this is much faster. I've only barely touched perlguts, perlapi, anc perlcall stuff with C modules, so I'm unsure, but I hope it works for you. At least it might get you started.

    --jb