Delegation Benchmarks

benchmark.rb

#
# A benchmark testing the performance of three methods of delegation:
#
# - Manually defining delegation methods
# - Metaprogramming using __send__
# - Metaprogramming without using __send__
#
# Note that the manual way of doing it is much faster if the arity of the
# target method is known. However, this benchmark is only meant to test
# the issue of __send__, and so we define the delegation methods with
# variable arguments.

require 'benchmark'

class Module
  def new_delegate(target, method)
    class_eval(<<-RUBY)
      def #{method}(*args, &block)
        #{target}.#{method}(*args, &block)
      end
    RUBY
  end

  def old_delegate(target, method)
    class_eval(<<-RUBY)
      def #{method}(*args, &block)
        #{target}.__send__(:#{method}, *args, &block)
      end
    RUBY
  end
end

class Target
  def hello(a, b, c); 'world'; end
end

class TargetWrapper
  def initialize
    @target = Target.new
  end
end

class MethodDelegate < TargetWrapper
  def hello(*args); @target.hello(*args); end
end

class OldDelegate < TargetWrapper
  old_delegate :@target, :hello
end

class NewDelegate < TargetWrapper
  new_delegate :@target, :hello
end

n      = 10_000_000
method = MethodDelegate.new
old    = OldDelegate.new
new    = NewDelegate.new

Benchmark.bm(7) do |x|
  x.report('method') { n.times { method.hello(1, 2, 3) } }
  x.report('old')    { n.times { old.hello(1, 2, 3) } }
  x.report('new')    { n.times { new.hello(1, 2, 3) } }
end