Just to throw this (possibly) related tidbit out: If you're interested in / worried about how much CPU time (as opposed to wall clock time) the process is using you might look at setting RLIMIT_CPU (either by your systems per-user login defaults, or your shell's ulimit command, or from Perl with BSD::Resource). Setting that sends a signal to the process when it has over stayed its welcome and run too long (on CPU doing actual work time).