Number of processes generated will be twice the number of forks as the following shells out for the ping.

 @ping_output=`ping $host 16 -n 4 2>/dev/null`;
[download]

Also this will be tainted. It might be worth looking at Net::Ping to reduce the processing load
http://cpan.perl.org/authors/id/B/BB/BBB/Net-Ping-2.31.readme

Is this having to go through a firewall because if you are not careful it may block you if you flood it with pings. Just because you can parallel the pings doesn't neccessarily meen the other end will like it.

Hope it Helps
UnderMine