use Benchmark;

push @lines, ((' ' x int rand 12) . (int rand 60000) . (' ' x int rand 2)) for 1..10000;

@pattern_list = qw(12345 12346 20034 8787 31337 31338 54320 54321);
my $bad_ports = '\b(?:12345|12346|20034|8787|31337|31338|54320|54321)\b';

timethese( 100, {
            'qr' => 'with_qr',
            '/o' => 'with_o'
});

sub with_qr {
  foreach $pattern (@pattern_list) {
    my $re = qr/\b${pattern}\b/;
    foreach $line (@lines) {
      $line =~ /$re/;
    }
  }
}

sub with_o {
  my $found = 0;
  for(@lines){ 
    (/\b(?:$bad_ports)\b/o);
  }
}