adapting it to a form that will be friendly for you is a tedious job

You shouldn't do it for me; you should do it for you. Unless you have a provably correct and realistically profiled single-threaded version; you'll never know if your multi-threaded version produces the correct result, or what if any benefit the threading achieved.

If it is so complex to knock up a single-threaded version of the problem, history shows that your chances of getting a multi-threaded version correct using the first approach you think of--even if you were full conversant with Perl's threading mechanisms, strengths and limitation, which I think you'll agree you are not--are slim to none.

But, 'tis your code and your call. Good luck!