Perf comparison of attr_reader vs methods on ruby 1.9.3

attr_reader.rb

require 'benchmark/ips'

class Foo1
  def initialize
    @bar = :bar
  end

  attr_reader :bar
end

class Foo2
  def initialize
    @bar = :bar
  end

  def bar
    @bar
  end
end

class Foo3
  def initialize
    @bar = :bar
  end

  def bar
    @bar ||= :bar
  end
end

foo1 = Foo1.new
foo2 = Foo2.new
foo3 = Foo3.new

Benchmark.ips do |r|
  r.report('attr_reader') { foo1.bar }
  r.report('method')      { foo2.bar }
  r.report('lazy method') { foo3.bar }
end

results.txt

Calculating -------------------------------------
         attr_reader     82088 i/100ms
              method     61836 i/100ms
         lazy method     49405 i/100ms
-------------------------------------------------
         attr_reader  3053024.0 (±0.2%) i/s -   15268368 in   5.001083s
              method  2846857.1 (±1.1%) i/s -   14284116 in   5.018190s
         lazy method  2385698.7 (±2.6%) i/s -   11956010 in   5.015812s