sub BenchIt {
    print "\n\n## $^O $]\n";
    use Benchmark qw {:all};
    our %hash;
    for (1001..2000) {
        $hash{$_}++;
    }
    our $key1 = 2000 - int rand 1001;
    our $key2 = 2000 - int rand 1001;
    $hash{$key1} = 1;
    $hash{$key2} = {1..10};
    our $xx_global;
    cmpthese (
        -2,
        {
            svExist   => 'for(1..10_000){$xx_global = exists $hash{$key1} ? 1 : 2}',
            svValue   => 'for(1..10_000){$xx_global = $hash{$key1} ? 1 : 2}',
            refExist  => 'for(1..10_000){$xx_global = exists $hash{$key2} ? 1 : 2}  ',
            refValue  => 'for(1..10_000){$xx_global = $hash{$key2} ? 1 : 2}',
        }
    );
    return;
}