$ perl -Mstrict -Mwarnings -E '
    use Benchmark qw{cmpthese};
    my @original_array = (10, 20);
     
    sub glob_double {
        local *copy = shift;
        for (@::copy) {
            $_ *= 2;
        }           
    }    
     
    sub ref_double {
        my $array_ref = shift;
        for (@$array_ref) {
            $_ *= 2;
        }           
    }    
     
    cmpthese(-1 => {
        glob => sub { @::array = @original_array; glob_double(*array) },
        ref  => sub { my @array = @original_array; ref_double(\@array) },
    });                                                                  
'
         Rate  ref glob
ref  546132/s   -- -28%
glob 763738/s  40%   --