Rails ActiveSupport::Autoload Benchmark

benchmark.rb

# Rails 3.2 @ d5d241cb2c696f13e2c16efca0d24565a6e1c0a5

require 'active_support/dependencies/autoload'
require 'benchmark'

GC.disable

FILES = (1..1_000_000).map do |file|
  ["Base#{file}".to_sym, "base/#{file}"]
end

def count_objects
  start = ObjectSpace.count_objects[:TOTAL]
  yield
  finish = ObjectSpace.count_objects[:TOTAL]
  puts "Object Count: #{finish-start}"
end

$add_autoloads = lambda do
  class Support
    FILES.each do |file|
      autoload(*file)
    end
  end
end

def super_benchmark(benchmark, name)
  count_objects do
    benchmark.report(name) do
      $add_autoloads.call
    end
  end
end

Benchmark.bm do |x|
  # Ruby w/o ActiveSupport::Autoload benchmark.
  class Support; end
  super_benchmark(x, 'ruby')

  # Original ActiveSupport::Autoload benchmark.
  Object.send(:remove_const, :Support)
  class Support; end
  Support.extend(ActiveSupport::Autoload)
  super_benchmark(x, 'orig')

  # Modified ActiveSupport::Autoload benchmark.
  module ActiveSupport
    module Autoload
      def autoload(const_name, path = @@at_path)
        unless path
          full = [name, @@under_path, const_name.to_s, path].compact.join("::")
          path = Inflector.underscore(full)
        end

        if @@eager_autoload
          @@autoloads[const_name] = path
        end

        super const_name, path
      end
    end
  end

  Object.send(:remove_const, :Support)
  class Support; end
  Support.extend(ActiveSupport::Autoload)

  super_benchmark(x, 'modi')
end

results.txt

       user     system      total        real
ruby  1.620000   0.170000   1.790000 (  1.802548)
Object Count: 3000184
orig  6.350000   0.500000   6.850000 (  7.040592)
Object Count: 9000139
modi  2.660000   0.180000   2.840000 (  3.014158)
Object Count: 3000184