Rate unpack substr  subst     re  readl
unpack 29656695/s     --    -5%    -8%   -14%   -16%
substr 31367657/s     6%     --    -3%    -9%   -11%
subst  32410531/s     9%     3%     --    -6%    -8%
re     34622792/s    17%    10%     7%     --    -2%
readl  35251272/s    19%    12%     9%     2%     --