In anticipation of <angry> replies </angry> : ) Do you REALLY need to worry? If your program is being spawned by something like apache (cgi etc) , then the creation of different threads for many instances of your program is being taken care of at another level.

Is your program 'linear' (wrong word) in it's execution, or are there things it should be doing whilst waiting on something else? recent discussion reveals Perl Multithreading in relation to scheduling.