It'll probably just make things run a little more slowly on the server, unless the loop body is really, really resource-hungry. To see if there are any rogue perls out there, just do a top or ps -ef|grep perl. If your tty is configured properly, the way to stop a runaway program is to hit ^C.

Update: That being said, there are certain system calls that can suck up resources a lot faster than you might think, so do be careful out there.