As a first step: daemonize your script and reboot the machine.

Always test under real-life conditions...

Concerning your question:
I don't know if any signal must be send in this case, googling didn't help and I'm to tired right now to dig further, sorry :(

FWIW: I experimented a little with this code

sub handler {
    my $sig = shift;
    `echo $sig >> ~/scratch/testsig`;
    exit if grep /$sig/, qw/INT TERM KILL CHLD ABRT HUP QUIT/;
}

$SIG{$_} = \&handler foreach keys %SIG;

while(1){}
[download]

kind regards,
tomte

Hlade's Law:

If you have a difficult task, give it to a lazy person --
they will find an easier way to do it.