This is Perl 5.010001
           Rate  range repeat  isook unpack substr
range  117311/s     --    -6%    -7%   -24%   -81%
repeat 124414/s     6%     --    -2%   -20%   -80%
isook  126456/s     8%     2%     --   -18%   -79%
unpack 155069/s    32%    25%    23%     --   -74%
substr 607361/s   418%   388%   380%   292%     --