Rate derived baseobj    hash
derived 1641/s      --     -0%    -79%
baseobj 1649/s      0%      --    -79%
hash    7876/s    380%    378%      --

##</code><code>##

#!/usr/bin/perl
use strict;
use warnings;

package ClassBase;

sub new {
    my ($class, $hash) = @_;
    return bless $hash, $class;
}

sub getter {
    my ($self) = @_;
    return $self->{1};
}

package Derived;

use parent -norequire => 'ClassBase';

sub new {
    my ($class, $hash) = @_;
    return $class->SUPER::new ($hash);
}

package main;

use Benchmark qw(cmpthese);

my %hash = 1 .. 10;
my $baseobj  = ClassBase->new (\%hash);
my $derived  = Derived->new (\%hash);
my $dump;

cmpthese(-1,
    {
     baseobj => sub {$dump = $baseobj->getter() for 1 .. 1000},
     derived => sub {$dump = $derived->getter() for 1 .. 1000},
     hash => sub {$dump = $hash{1} for 1 .. 1000},
     }
);