attr_reader_method_benchmark.rb

class MethodClass
  def initialize; @test = 1; end
  def test
    @test
  end
end

class ReaderClass
  attr_reader :test
  def initialize; @test = 1; end
end

require 'benchmark'
n = 10_000_000
m = MethodClass.new
r = ReaderClass.new
Benchmark.bm(15) do |x|
  x.report("method call") { n.times { m.test } }
  x.report("reader call") { n.times { r.test } }
end

# For 10_000_000 calls:
#
# on ruby 1.8.7 (2010-04-19 patchlevel 253) [i686-darwin10.3.2], MBARI 0x6770, Ruby Enterprise Edition 2010.02
#                      user     system      total        real
# method call      2.980000   0.000000   2.980000 (  3.019924)
# reader call      1.910000   0.000000   1.910000 (  1.922055)
#
# on ruby 1.9.2p0 (2010-08-18 revision 29036) [x86_64-darwin10.4.0]
# 
#                      user     system      total        real
# method call      1.480000   0.000000   1.480000 (  1.481865)
# reader call      1.480000   0.010000   1.490000 (  1.476539)