So here are my benchmark results on Win XP with version 5.10. Mine are drastically different showing the 'use constant' is fastest. Do the newer versions of Perl treat constants differently?
mod[3]sub[3]
my[3]local[3]
ref[3]alias[3]
            Rate CAlias   CRef CLocal    CMy   CSub   CMod
CAlias 3014249/s     --    -9%   -20%   -22%   -27%   -45%
CRef   3305288/s    10%     --   -12%   -14%   -20%   -40%
CLocal 3749148/s    24%    13%     --    -3%   -10%   -32%
CMy    3849294/s    28%    16%     3%     --    -7%   -30%
CSub   4149204/s    38%    26%    11%     8%     --   -25%
CMod   5504587/s    83%    67%    47%    43%    33%     --

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In reply to Re^4: my $var; vs. use constant VAR = ''; by donaldhasson
in thread my $var = ''; vs. use constant VAR => ''; by antihero

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