More precisely,

• Make sure you are using Text::CSV version 1 or greater

  # Use Text::CSV_XS if it's available or the
  # slower Pure Perl implementation otherwise.
  use Text::CSV 1.000;
  
  ...
  my $csv_reader = Text::CSV->new();
  ...
  [download]

  and make sure you have Text::CSV_XS installed.

  >perl -e"use Text::CSV_XS"
  [download]

• Or just use Text::CSV_XS directly.

  use Text::CSV_XS;
  
  ...
  my $csv_reader = Text::CSV_XS->new();
  ...
  [download]

The XS version is 50x faster than the Pure Perl implementation according to the author. Both of the above methods will use the XS version.