OpenStruct vs Struct vs Hash vs Data performance

open_struct_struct_hash_data.rb

require 'benchmark'
require 'ostruct'

REP = 1000000
ACCESS_REP = 4

User = Struct.new(:name, :age)

UserData = Data.define(:name, :age)

USER = "User".freeze
AGE = 21
HASH = {:name => USER, :age => AGE}.freeze

Benchmark.bm 20 do |x|
  x.report 'OpenStruct slow' do
    REP.times do |index|
      instance = OpenStruct.new(:name => "User", :age => 21)
      ACCESS_REP.times do
        [instance.name, instance.age]
      end
    end
  end

  x.report 'OpenStruct fast' do
    REP.times do |index|
      instance = OpenStruct.new(HASH)
      ACCESS_REP.times do
        [instance.name, instance.age]
      end
    end
  end

  x.report 'Struct slow' do
    REP.times do |index|
      instance = User.new("User", 21)
      ACCESS_REP.times do
        [instance.name, instance.age]
      end
    end
  end

  x.report 'Struct fast' do
    REP.times do |index|
      instance = User.new(USER, AGE)
      ACCESS_REP.times do
        [instance.name, instance.age]
      end
    end
  end

  x.report 'Hash slow' do
    REP.times do |index|
      instance = {:name => 'User', :age => 21}
      ACCESS_REP.times do
        [instance[:name], instance[:age]]
      end
    end
  end

  x.report 'Hash fast' do
    REP.times do |index|
      instance = {:name => USER, :age => AGE}
      ACCESS_REP.times do
        [instance[:name], instance[:age]]
      end
    end
  end

  x.report 'Data slow' do
    REP.times do |index|
      instance = UserData.new("User", 21)
      ACCESS_REP.times do
        [instance.name, instance.age]
      end
    end
  end

  x.report 'Data fast' do
    REP.times do |index|
      instance = UserData.new(USER, AGE)
      ACCESS_REP.times do
        [instance.name, instance.age]
      end
    end
  end
end

output

# NOTE: Ran on arm64 Macbook m1 with ruby 3.2.2 compiled by ASDF/ruby-build
                       user     system      total        real
OpenStruct slow        6.366970   0.025408   6.392378 (  6.392326)
OpenStruct fast        6.321198   0.020139   6.341337 (  6.341283)
Struct slow            0.387496   0.001697   0.389193 (  0.389192)
Struct fast            0.364341   0.001684   0.366025 (  0.366025)
Hash slow              0.537750   0.001559   0.539309 (  0.539306)
Hash fast              0.520458   0.001227   0.521685 (  0.521703)
Data slow              0.493237   0.001876   0.495113 (  0.495149)
Data fast              0.469824   0.001703   0.471527 (  0.471534)