From what I can see, the functions you listed should be fine. My point about the single script went back to the initial problem. Your initial problem was that the main perl script was taking 75% CPU. As was pointed out, this was likely caused by the thread module itself. If you modified your script as I suggested, the perl script should end up using very little CPU, and could therefore run fine together on a single system. Of course, your mileage may vary...