use Benchmark qw(:all);
my @lines = split /\n/, <<EOF;
vlan 107
vlan 121
vlan 122,127,129,137
vlan
EOF
pop @lines;
cmpthese(
  500_000,
  { 'split-split' => sub {
                     my @copy = @lines;
                     foreach my $line (@copy) {
                         my (undef, $vlans) = split /\s+/, $line;
                         my @items = split /,/, $vlans;
                      }
                 },
     '/g'    => sub {
                      my @copy = @lines;
                      foreach my $line (@copy) {
                         my @items = ($line =~ /(\d+)/g);
                      }
                },
    'sub-split' => sub {
                      my @copy = @lines;
                      foreach my $line (@copy) {
                         s/vlan //;
                         my @items = split /,/, $line;
                      }
                   },
   }
);