Teste comparando Moose (virtual memory size 50204 kb) e Moo (virtual memory size 31364 kb) através do modulo Memory::Usage

a.pl

use strict;
use warnings;
use feature 'say';

use Memory::Usage;
my $mu = Memory::Usage->new();

$mu->record('starting work');

package Foo;
use Moose;
#use Moo;

has 'name' => ( is => 'ro', required => 1 );

sub run { my ($self) = @_; say $self->name }

1;

package main;

$mu->record('after create package Foo');

Foo->new(name => 'bar')->run;

$mu->record('after something_memory_intensive()');

$mu->dump();

moo.txt

$ perl a.pl
bar
  time    vsz (  diff)    rss (  diff) shared (  diff)   code (  diff)   data (  diff)
     0  28468 ( 28468)   4028 (  4028)   1892 (  1892)   1256 (  1256)   2632 (  2632) starting work
     0  31236 (  2768)   4876 (   848)   1936 (    44)   1256 (     0)   3292 (   660) after create package Foo
     0  31364 (   128)   5064 (   188)   1956 (    20)   1256 (     0)   3420 (   128) after something_memory_intensive()

moose.txt

tpecze-@tpecze-desktop:~$ perl a.pl
bar
  time    vsz (  diff)    rss (  diff) shared (  diff)   code (  diff)   data (  diff)
     0  50204 ( 50204)  13448 ( 13448)   2084 (  2084)   1256 (  1256)  11624 ( 11624) starting work
     0  50204 (     0)  13448 (     0)   2084 (     0)   1256 (     0)  11624 (     0) after create package Foo
     0  50204 (     0)  13448 (     0)   2084 (     0)   1256 (     0)  11624 (     0) after something_memory_intensive()