At root Perl is interpreted not compiled. For things like string manipulation and regular expression parsing Perl performs very well because most of the time is spent in well crafted C code (in the interpreter). For code such as your sample which is CPU intensive but doesn't take advantage of Perl's strengths you simply hit the penalty for using an interpreter.

For most applications that take advantage of Perl's strengths the performance is fine. Even for many applications that don't play so well to Perl's run time strengths, the time to craft a solution in Perl and execute it is very often shorter than the time to write and execute a similar application using a different language, even though the run time may be much shorter in the other language.