bench.rb

# frozen_string_literal: true

begin
  require "bundler/inline"
rescue LoadError => e
  $stderr.puts "Bundler version 1.10 or later is required. Please update your Bundler"
  raise e
end

gemfile(true) do
  source "https://rubygems.org"
  gem "activemodel", path: "/Users/byroot/src/github.com/Shopify/rails"
  gem "benchmark-ips"
end

require 'active_model'

class InscribingType
  def changed_in_place?(raw_old_value, new_value)
    false
  end

  def cast(value)
    value
  end

  def serialize(value)
    value
  end

  def deserialize(value)
    value
  end
end

type = InscribingType.new

ActiveModel::Attribute.optimization_enabled = !!ENV["ENABLE_OPT"]

Benchmark.ips do |x|
  x.report("#value (#{ActiveModel::Attribute.optimization_enabled ? 'opt' : 'orig'})") do
    attribute = ActiveModel::Attribute.from_database(nil, "a value", type)
    # We mix calls here to cause shape transitions, hence cache misses
    attribute.value
    attribute.value
    attribute.value_for_database
    attribute.value
    attribute.value_for_database
  end
  x.save!(RubyVM::YJIT.enabled? ? "/tmp/attr-bench-yjit.dump" : "/tmp/attr-bench.dump") 
  x.compare!(order: :baseline)
end

results.txt

$ ENABLE_OPT=1 ruby  -v /tmp/attribute-bench.rb 
ruby 3.2.1 (2023-02-08 revision 31819e82c8) [arm64-darwin22]
Warming up --------------------------------------
        #value (opt)   205.105k i/100ms
Calculating -------------------------------------
        #value (opt)      2.045M (± 0.8%) i/s -     10.255M in   5.014536s

Comparison:
       #value (orig):  1811240.2 i/s
        #value (opt):  2045238.9 i/s - 1.13x  faster

yjit-results.txt

$ ENABLE_OPT=1 ruby --yjit  -v /tmp/attribute-bench.rb 
ruby 3.2.1 (2023-02-08 revision 31819e82c8) +YJIT [arm64-darwin22]
Warming up --------------------------------------
        #value (opt)   508.880k i/100ms
Calculating -------------------------------------
        #value (opt)      6.347M (± 1.4%) i/s -     32.059M in   5.051888s

Comparison:
       #value (orig):  4379180.3 i/s
        #value (opt):  6347280.7 i/s - 1.45x  faster