method-cache-test.rb

require 'benchmark'

module A
end

class DefinedMethodStyle
  def dont_bust_cache(*)
    Object.new
    nil
  end

  def bust_cache_class(*)
    Class.new
    nil
  end

  def bust_cache_extend(*)
    Object.new.extend(A)
    nil
  end
end

class MethodMissingStyle
  def _dont_bust_cache(*)
    Object.new
    nil
  end

  def _bust_cache_class(*)
    Class.new
    nil
  end

  def _bust_cache_extend(*)
    Object.new.extend(A)
    nil
  end

  def method_missing(method, *args)
    if method == :bust_cache_class
      _bust_cache_class(*args)
    elsif method == :bust_cache_extend
      _bust_cache_extend(*args)
    elsif method == :dont_bust_cache
      _dont_bust_cache(*args)
    end
  end
end

dms = DefinedMethodStyle.new
mms = MethodMissingStyle.new
n = 1_000_000

puts "Controls"
controls = Benchmark.bm do |bm|
  bm.report("Object.new") { n.times { Object.new } }
  bm.report("Class.new") { n.times { Class.new } }
  bm.report("Object.new.extend(A)") { n.times { Object.new.extend(A) } }
end

puts "Tests"
tests = Benchmark.bm do |bm|
   bm.report("defined methods, not busting cache") { n.times { |i| dms.dont_bust_cache(i) } }
   bm.report("method_missing dispatch, not busting cache") { n.times { |i| mms.dont_bust_cache(i) } }
   bm.report("defined methods, busting cache with Class.new") { n.times { |i| dms.bust_cache_class(i) } }
   bm.report("method_missing dispatch, busting cache with Class.new") { n.times { |i| mms.bust_cache_class(i) } }
   bm.report("defined methods, busting cache with Object.new.extend(A)") { n.times { |i| dms.bust_cache_extend(i) } }
   bm.report("method_missing dispatch, busting cache with Object.new.extend(A)") { n.times { |i| mms.bust_cache_extend(i) } }
end

puts "Adjusted for overhead"
tests.each do |test|
  puts test.label

  control = controls[tests.find_index(test) / 2]
  puts "Approximate method resolution time: #{test.real - control.real}"
end