There was a vanilla arc profiler pushed to anarki a while ago - see http://arclanguage.org/item?id=5318 ... it requires you to specify which functions to profile. Which could be more or less useful, depending on what you need.

I'd guess that any kind of decent profiler has to get in under the hood somehow - so to get something similar working for vanilla arc you'd need to go hacking ac.scm, probably somewhere inside

  (define (ac-call fn args env)
    ...