use Benchmark qw( cmpthese );
use List::Util qw( shuffle );

my $range = 100000;
my $ITERS = 30000;
my (%HASH, $HASH_REF);
for(my $iter = 1; $iter <= $ITERS; $iter++){
    my $random_number = int(rand($range));
    $HASH{$random_number} = 1;
    $HASH_REF->{$random_number} = 1;
}

my @rand = map { int rand $range } 1 .. $ITERS;
my @hits = shuffle keys %HASH;
my @miss = grep { ! exists $HASH{$_} } 0 .. $range;

cmpthese( -2, { hash_r => sub { map { exists $HASH{$_} } @rand },
                ref_r => sub { map { exists $HASH_REF->{$_} } @rand },
                hash_h => sub { map { exists $HASH{$_} } @hits },
                ref_h => sub { map { exists $HASH_REF->{$_} } @hits },
                hash_m => sub { map { exists $HASH{$_} } @miss },
                ref_m => sub { map { exists $HASH_REF->{$_} } @miss },
          } );
__END__
         Rate  ref_m hash_m  ref_r  ref_h hash_r hash_h
ref_m  57.8/s     --   -10%   -56%   -58%   -59%   -61%
hash_m 64.2/s    11%     --   -51%   -54%   -54%   -56%
ref_r   131/s   127%   105%     --    -5%    -6%   -11%
ref_h   139/s   140%   117%     6%     --    -0%    -6%
hash_r  140/s   141%   117%     6%     0%     --    -5%
hash_h  147/s   155%   130%    12%     6%     6%     --

##</code><code>##

my @rand = ( map { int rand $range } 1 .. $ITERS )[0 .. $ITERS/2];
my @hits = ( shuffle keys %HASH )[0 .. $ITERS/2];
my @miss = ( grep { ! exists $HASH{$_} } 0 .. $range )[0 .. $ITERS/2];

##</code><code>##

        Rate  ref_h hash_h  ref_r  ref_m hash_r hash_m
ref_h  229/s     --   -10%   -13%   -18%   -22%   -30%
hash_h 254/s    11%     --    -3%    -9%   -14%   -22%
ref_r  263/s    15%     3%     --    -6%   -11%   -19%
ref_m  279/s    22%    10%     6%     --    -5%   -14%
hash_r 295/s    29%    16%    12%     6%     --   -10%
hash_m 326/s    42%    28%    24%    17%    11%     --