$ perl5.8.4 test.pl
           Rate  c_pp  c_xs  cbxs  perl
c_pp 9.63e-02/s    --  -94%  -97%  -98%
c_xs     1.65/s 1616%    --  -42%  -57%
cbxs     2.84/s 2845%   72%    --  -27%
perl     3.88/s 3932%  135%   37%    --
$ perl5.20.1 test.pl
Use of uninitialized value in split at test.pl line 13, <$fh> line 200000.
Use of uninitialized value in split at test.pl line 13, <$fh> line 200000.
Use of uninitialized value in split at test.pl line 13, <$fh> line 200000.
Use of uninitialized value in split at test.pl line 13, <$fh> line 200000.
           Rate  c_pp  c_xs  cbxs  perl
c_pp 8.65e-02/s    --  -96%  -97%  -98%
c_xs     2.07/s 2295%    --  -27%  -53%
cbxs     2.84/s 3179%   37%    --  -35%
perl     4.40/s 4980%  112%   55%    --