I think it would be better to rewrite loop in the following way:

foreach $host (@host_array) {
    if( $p->ping($host, 2) ) {
        print "$host is alive.\n";
    }
    else {
        print "$host is dead\n";
    }
}
[download]

Or you can face situation when some host dead and alive (if first ping fails and second successful) or neither dead nor alive (if first ping succeeds and second fails).