use Benchmark qw (cmpthese);

@data = ('foo 1000 bar 1000', 'foo 1000 bar 500',
         'foo 500 bar 1000', 'foo 500 bar 500',
         'foo 1 bar 1',
         'foo 1 bar 2',
         'foo 2 bar 2',
         'foo 10000 bar 1000',
         'foo 10000 bar 10000',
         );

my $tot = 5;

my $count = 100000;

cmpthese($count, {
        'ref' => sub {
                my $x=0;
                for (@data) {
                        $x++ if /^\S+ (\d+) \S+ \1$/;
                }
                die "$x" unless $x == $tot;
        },
        'split' => sub {
                my $x=0;
                for (@data) {
                        my @arr = split /\s+/;
                        $x++ if $arr[1] == $arr[3];
                }
                die $x unless $x == $tot;
        },
        'simple' => sub {
                my $x=0;
                for (@data) {
                        $x++ if !m/foo (\d+) bar (\d+)/ || $1 == $2;
                }
                die unless $x == $tot;
        },
});

__END__

##</code><code>##

           Rate   split  simple backref
split    4329/s      --    -31%    -66%
simple   6313/s     46%      --    -50%
backref 12658/s    192%    101%      --