benchmark_dynamic_method_defs

require 'benchmark/ips'

module ExtraMath
  def self.build_math(attr_name)
    attr_name = attr_name.to_s
    class_eval %Q{
      def #{attr_name}(x)
      x + x
      end
    }
  end

  build_math(:do_mathes)

  define_method "do_maths" do |x|
    x + x
  end

  def do_math(x)
    x + x
  end
end

class TestMath
  include ExtraMath
end

t = TestMath.new

Benchmark.ips do |x|
  # Configure the number of seconds used during
  # the warmup phase (default 2) and calculation phase (default 5)
  x.config(:time => 5, :warmup => 2)

  # These parameters can also be configured this way
  x.time = 5
  x.warmup = 2

  x.report("normal maths") do
    t.do_math(2)
  end

  x.report("define_method maths") do
    t.do_maths(2)
  end

  x.report("class_eval maths") do
    t.do_mathes(2)
  end

  x.compare!
end

This gist is here to test the performance of define_method vs class_eval at runtime. You will need to have Benchmark-IPS installed to run this gist.

Warming up --------------------------------------
        normal maths   217.946k i/100ms
 define_method maths   200.375k i/100ms
    class_eval maths   234.464k i/100ms
Calculating -------------------------------------
        normal maths      7.040M (± 7.8%) i/s -     35.089M in   5.016121s
 define_method maths      5.294M (±11.1%) i/s -     26.049M in   5.011117s
    class_eval maths      7.051M (± 7.7%) i/s -     35.170M in   5.019806s

Comparison:
    class_eval maths:  7051160.4 i/s
        normal maths:  7040465.6 i/s - same-ish: difference falls within error
 define_method maths:  5294350.6 i/s - 1.33x  slower