As a philosophical point, don't worry about performance if it's adequate, unless you know that the recursive algorithm is incredibly far from optimal, like the using the most naive recursion to calculate Fibonacci numbers. Without the complete source, at least for the routines in question, nobody here could give a sensible answer to the question as to whether you should worry about potential performance problems, or not. Don't worry; as ikegami said, Perl handles recursion perfectly well.