perlbrew exec bench_script.pl

# Other versions of Perl, omitted for brevity - see original link
#   for the "gories..."
...

perl-5.26.0
==========
             Rate      index      regex      split filehandle
index      3.00/s         --       -25%       -49%       -53%
regex      3.98/s        33%         --       -33%       -37%
split      5.91/s        97%        49%         --        -6%
filehandle 6.31/s       111%        59%         7%         --