sub prepData2 {
    my $refData = shift;
    @$refData = ( map { log $_ } 1 .. 100 );
}
__END__
                  Rate     array_out array_ref_out1  array_ref_in array_ref_out2
array_out      11801/s            --           -28%          -28%           -39%
array_ref_out1 16406/s           39%             --           -1%           -15%
array_ref_in   16496/s           40%             1%            --           -14%
array_ref_out2 19238/s           63%            17%           17%             --