bench.rb

# frozen_string_literal: true

require 'bundler/inline'

gemfile(true) do
  source 'https://rubygems.org'
  gem 'activesupport', github: 'rails/rails'
  gem 'benchmark-ips'
end

require 'benchmark/ips'
require "active_support/core_ext/class/attribute"

module ActiveSupport
  module ClassAttribute # :nodoc:
    class << self
      def redefine(owner, name, value)
        if owner.singleton_class?
          owner.redefine_method(name) { value }
          owner.silence_redefinition_of_method(name)
        end

        owner.redefine_singleton_method(name) { value }
        owner.redefine_singleton_method("#{name}=") do |new_value|
          if owner.equal?(self)
            value = new_value
          else
            ::ActiveSupport::ClassAttribute.redefine(self, name, new_value)
          end
        end
      end
    end
  end
end

class Class
  def faster_class_attribute(*attrs, instance_accessor: true,
    instance_reader: instance_accessor, instance_writer: instance_accessor, instance_predicate: true, default: nil)

    class_methods, methods = [], []
    attrs.each do |name|
      unless name.is_a?(Symbol) || name.is_a?(String)
        raise TypeError, "#{name.inspect} is not a symbol nor a string"
      end

      name = name.to_sym
      ::ActiveSupport::ClassAttribute.redefine(self, name, default)

      unless singleton_class?
        methods << <<~RUBY if instance_reader
          silence_redefinition_of_method def #{name}
            defined?(@#{name}) ? @#{name} : self.class.#{name}
          end
        RUBY
      end

      methods << <<~RUBY if instance_writer
        silence_redefinition_of_method(:#{name}=)
        attr_writer :#{name}
      RUBY

      if instance_predicate
        class_methods << "silence_redefinition_of_method def #{name}?; !!self.#{name}; end"
        if instance_reader
          methods << "silence_redefinition_of_method def #{name}?; !!self.#{name}; end"
        end
      end
    end

    location = caller_locations(1, 1).first
    class_eval(["class << self", *class_methods, "end", *methods].join(";").tr("\n", ";"), location.path, location.lineno)
  end
end


class Foo
  class_attribute :old, :old_too
  faster_class_attribute :fast, :fast_too
end

class Bar < Foo
end

class Baz < Bar
end

class Other
end

FOO_INSTANCE = Foo.new

puts "==== definition ===="
Benchmark.ips do |x|
  x.report("old") { Other.class_attribute :attr1, :attr2, :attr3, :attr4, :attr5, :attr6, :attr7, :attr8, :attr9, :attr10 }
  x.report("new") { Other.faster_class_attribute :attr1, :attr2, :attr3, :attr4, :attr5, :attr6, :attr7, :attr8, :attr9, :attr10 }
  x.compare!(order: :baseline)
end

puts "==== class reader ===="
Benchmark.ips do |x|
  x.report("old") { Foo.old }
  x.report("new") { Foo.fast }
  x.compare!(order: :baseline)
end

puts "==== class inherited reader ===="
Benchmark.ips do |x|
  x.report("old") { Baz.old }
  x.report("new") { Baz.fast }
  x.compare!(order: :baseline)
end

puts "==== class writer ===="
Benchmark.ips do |x|
  x.report("old") { Foo.old = 42 }
  x.report("new") { Foo.fast = 42 }
  x.compare!(order: :baseline)
end

puts "==== instance reader ===="
Benchmark.ips do |x|
  x.report("old") { FOO_INSTANCE.old }
  x.report("new") { FOO_INSTANCE.fast }
  x.compare!(order: :baseline)
end

puts "==== instance writer ===="
Benchmark.ips do |x|
  x.report("old") { FOO_INSTANCE.old = 42}
  x.report("new") { FOO_INSTANCE.fast = 42 }
  x.compare!(order: :baseline)
end

interpreter.txt

$ ruby /tmp/class_attribute.rb 
Fetching gem metadata from https://rubygems.org/..........
Resolving dependencies...
==== definition ====
ruby 3.3.4 (2024-07-09 revision be1089c8ec) [arm64-darwin23]
Warming up --------------------------------------
                 old   359.000 i/100ms
                 new   648.000 i/100ms
Calculating -------------------------------------
                 old      3.782k (± 4.4%) i/s -     19.027k in   5.040409s
                 new      6.684k (± 3.7%) i/s -     33.696k in   5.047975s

Comparison:
                 old:     3782.3 i/s
                 new:     6684.2 i/s - 1.77x  faster

==== class reader ====
ruby 3.3.4 (2024-07-09 revision be1089c8ec) [arm64-darwin23]
Warming up --------------------------------------
                 old     3.472M i/100ms
                 new     3.477M i/100ms
Calculating -------------------------------------
                 old     34.627M (± 1.5%) i/s -    173.583M in   5.014081s
                 new     33.503M (± 1.3%) i/s -    170.353M in   5.085518s

Comparison:
                 old: 34627278.8 i/s
                 new: 33503236.6 i/s - 1.03x  slower

==== class inherited reader ====
ruby 3.3.4 (2024-07-09 revision be1089c8ec) [arm64-darwin23]
Warming up --------------------------------------
                 old     3.543M i/100ms
                 new     3.539M i/100ms
Calculating -------------------------------------
                 old     34.971M (± 2.5%) i/s -    177.131M in   5.068421s
                 new     35.316M (± 0.7%) i/s -    176.926M in   5.010014s

Comparison:
                 old: 34971144.7 i/s
                 new: 35316427.3 i/s - same-ish: difference falls within error

==== class writer ====
ruby 3.3.4 (2024-07-09 revision be1089c8ec) [arm64-darwin23]
Warming up --------------------------------------
                 old   184.659k i/100ms
                 new     1.769M i/100ms
Calculating -------------------------------------
                 old      1.834M (± 1.5%) i/s -      9.233M in   5.035024s
                 new     17.722M (± 2.9%) i/s -     90.220M in   5.095668s

Comparison:
                 old:  1834149.6 i/s
                 new: 17722346.6 i/s - 9.66x  faster

==== instance reader ====
ruby 3.3.4 (2024-07-09 revision be1089c8ec) [arm64-darwin23]
Warming up --------------------------------------
                 old     1.807M i/100ms
                 new     1.804M i/100ms
Calculating -------------------------------------
                 old     18.065M (± 2.7%) i/s -     90.366M in   5.006426s
                 new     18.149M (± 1.0%) i/s -     91.989M in   5.068965s

Comparison:
                 old: 18065296.8 i/s
                 new: 18149220.0 i/s - same-ish: difference falls within error

==== instance writer ====
ruby 3.3.4 (2024-07-09 revision be1089c8ec) [arm64-darwin23]
Warming up --------------------------------------
                 old     3.888M i/100ms
                 new     3.829M i/100ms
Calculating -------------------------------------
                 old     38.740M (± 2.8%) i/s -    194.413M in   5.022806s
                 new     38.528M (± 2.4%) i/s -    195.269M in   5.071387s

Comparison:
                 old: 38740467.7 i/s
                 new: 38528036.9 i/s - same-ish: difference falls within error

yjit.txt

$ ruby --yjit /tmp/class_attribute.rb 
Fetching gem metadata from https://rubygems.org/..........
Resolving dependencies...
==== definition ====
ruby 3.3.4 (2024-07-09 revision be1089c8ec) +YJIT [arm64-darwin23]
Warming up --------------------------------------
                 old   363.000 i/100ms
                 new   671.000 i/100ms
Calculating -------------------------------------
                 old      3.745k (± 3.6%) i/s -     18.876k in   5.047932s
                 new      6.612k (± 3.2%) i/s -     33.550k in   5.079578s

Comparison:
                 old:     3744.5 i/s
                 new:     6611.9 i/s - 1.77x  faster

==== class reader ====
ruby 3.3.4 (2024-07-09 revision be1089c8ec) +YJIT [arm64-darwin23]
Warming up --------------------------------------
                 old     4.406M i/100ms
                 new     4.269M i/100ms
Calculating -------------------------------------
                 old     43.817M (± 4.5%) i/s -    220.324M in   5.038915s
                 new     44.779M (± 2.8%) i/s -    226.263M in   5.057146s

Comparison:
                 old: 43816694.4 i/s
                 new: 44778662.3 i/s - same-ish: difference falls within error

==== class inherited reader ====
ruby 3.3.4 (2024-07-09 revision be1089c8ec) +YJIT [arm64-darwin23]
Warming up --------------------------------------
                 old     4.609M i/100ms
                 new     4.420M i/100ms
Calculating -------------------------------------
                 old     44.458M (± 4.5%) i/s -    225.817M in   5.090329s
                 new     44.931M (± 3.2%) i/s -    225.431M in   5.022544s

Comparison:
                 old: 44457947.2 i/s
                 new: 44930756.7 i/s - same-ish: difference falls within error

==== class writer ====
ruby 3.3.4 (2024-07-09 revision be1089c8ec) +YJIT [arm64-darwin23]
Warming up --------------------------------------
                 old   251.197k i/100ms
                 new     4.098M i/100ms
Calculating -------------------------------------
                 old      2.561M (± 2.1%) i/s -     12.811M in   5.004196s
                 new     43.004M (± 3.3%) i/s -    217.210M in   5.056701s

Comparison:
                 old:  2561173.8 i/s
                 new: 43004422.5 i/s - 16.79x  faster

==== instance reader ====
ruby 3.3.4 (2024-07-09 revision be1089c8ec) +YJIT [arm64-darwin23]
Warming up --------------------------------------
                 old     4.007M i/100ms
                 new     3.908M i/100ms
Calculating -------------------------------------
                 old     38.408M (± 4.3%) i/s -    192.318M in   5.017940s
                 new     38.316M (± 3.3%) i/s -    195.391M in   5.105697s

Comparison:
                 old: 38408490.1 i/s
                 new: 38316383.2 i/s - same-ish: difference falls within error

==== instance writer ====
ruby 3.3.4 (2024-07-09 revision be1089c8ec) +YJIT [arm64-darwin23]
Warming up --------------------------------------
                 old     3.914M i/100ms
                 new     4.035M i/100ms
Calculating -------------------------------------
                 old     40.173M (± 1.9%) i/s -    203.548M in   5.068536s
                 new     40.273M (± 3.1%) i/s -    201.771M in   5.015094s

Comparison:
                 old: 40172937.9 i/s
                 new: 40273498.6 i/s - same-ish: difference falls within error