cchan.acsys.com.1.256% cat aaa3.pl 
use Benchmark; 
my $count = 1000000;
our $str = "a:b:c:d:e:ff:g:h:i:j:k:l:m:n:o:p:q:r:s:t:u:v:w:x:y:z";
timethese($count, {
          'slice' => sub { (undef, my $foo) = split /:/,$str; },
               'count' => sub { my $foo = (split/:/,$str,3)[1]; },
           });