Perl Proxy Tester with Threads

#!/usr/bin/perl -w
# Proxy list tester using threads
#
# INPUT file -> "proxy"
# format -> IP:PORT on each row
#
# OUTPUT file -> "proxy.log"

use threads;
use WWW::Mechanize;

$nn = 25; # number of simultaneous connections
$timeout = 10; # proxy request timeout (secs)

sub start_thread {
        my @args = @_;
    my $go = WWW::Mechanize->new( agent=> "Mozilla/5.0", timeout => $timeout);
    $go->proxy(['http'], 'http://'.$args[0].'/');
    print "Testing: ".$args[0]."\n";
    eval {
     $go->get('http://automation.whatismyip.com/n09230945.asp');
    };
    if ($@) { return; }
    $match = $go->content;
    my($crap,$ip)=split(/^(.*):/,$args[0]);
    if ($match =~ /$ip/) {
        open(LOG,">> proxy.log"); print LOG $args[0]."\n"; close(LOG);
        print "======> UP $args[0] <=======\n";
    }
}

@proxy=`cat proxy`;
$n = 0;
foreach $i (@proxy) {
chomp($i);
$thr[$n] = threads->create('start_thread', $i);
$n++;
if ($n == $nn) {
 `sleep $timeout`;
 for ($x=0; $x<$nn;$x++) {
  $thr[$x]->join();
 }
 $n = 0;
}

}