Thanks for sharing this blog. I modified the script to use Benchmark::Forking and re-ran. It changed the values slightly, but not by too much.

                 Rate PIR fast  PIR File::Find perl readdir find pipe iter find pipe
PIR fast       1.46/s       --  -1%       -26%         -47%           -69%      -71%
PIR            1.47/s       1%   --       -25%         -47%           -68%      -70%
File::Find     1.98/s      35%  34%         --         -29%           -58%      -60%
perl readdir   2.78/s      90%  88%        40%           --           -41%      -44%
find pipe iter 4.68/s     219% 217%       136%          68%             --       -6%
find pipe      5.00/s     241% 239%       153%          80%             7%        --

Cheers, lbe