memoist_bench.rb

require 'memoist'
require 'benchmark'

class Normal
  def value
    1000.times do |i|
      123.45 * 3323.2 / i + 1
    end
  end

  def calc
    1000.times do |i|
      i * value
    end
  end
end

class Memoized < Normal
  def value
    @_value ||= super
  end
end

class Memoisted < Normal
  extend Memoist
  memoize :value
end

puts "Without args"

Benchmark.bm do |x|
  x.report("normal:") { Normal.new.calc }
  x.report("memoized:") { Memoized.new.calc }
  x.report("memoisted:"){ Memoisted.new.calc }
end


class Normal
  def value(arg)
    1000.times do |i|
      123.45 * arg / i + 1
    end
  end

  def calc
    1000.times do |i|
      i * value(5)
    end
  end
end

class Memoized < Normal
  def value(arg)
    @_value ||= {}
    @_value[arg] ||= super arg
  end
end

class Memoisted < Normal
  extend Memoist
  memoize :value
end

puts "With args: "

Benchmark.bm do |x|
  x.report("normal:") { Normal.new.calc }
  x.report("memoized:") { Memoized.new.calc }
  x.report("memoisted:"){ Memoisted.new.calc }
end

Results:

Without args
       user     system      total        real
normal:  0.260000   0.000000   0.260000 (  0.260516)
memoized:  0.000000   0.000000   0.000000 (  0.000541)
memoisted:  0.000000   0.000000   0.000000 (  0.002366)
With args: 
       user     system      total        real
normal:  0.260000   0.000000   0.260000 (  0.260472)
memoized:  0.000000   0.000000   0.000000 (  0.000667)
memoisted:  0.240000   0.000000   0.240000 (  0.244774)