OpenStruct vs Struct vs Hash performance

open_struct_struct_hash.rb

require 'benchmark'
require 'ostruct'

REP = 1000000

User = Struct.new(: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|
       OpenStruct.new(:name => "User", :age => 21)
    end
  end

  x.report 'OpenStruct fast' do
    REP.times do |index|
       OpenStruct.new(HASH)
    end
  end

  x.report 'Struct slow' do
    REP.times do |index|
       User.new("User", 21)
    end
  end

  x.report 'Struct fast' do
    REP.times do |index|
       User.new(USER, AGE)
    end
  end

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

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

output

                           user     system      total        real
OpenStruct slow        8.150000   0.000000   8.150000 (  8.153797)
OpenStruct fast        7.980000   0.000000   7.980000 (  7.983929)
Struct slow            0.270000   0.000000   0.270000 (  0.268514)
Struct fast            0.200000   0.000000   0.200000 (  0.196950)
Hash slow              0.580000   0.000000   0.580000 (  0.584160)
Hash fast              0.460000   0.000000   0.460000 (  0.458502)

Ruby 3.3.4 on arm64 Macbook M3:

                           user     system      total        real
OpenStruct slow        3.804766   0.029756   3.834522 (  3.841408)
OpenStruct fast        3.601886   0.008229   3.610115 (  3.615765)
Struct slow            0.093334   0.000282   0.093616 (  0.093774)
Struct fast            0.081255   0.000151   0.081406 (  0.081472)
Hash slow              0.058589   0.000235   0.058824 (  0.058935)
Hash fast              0.047965   0.000229   0.048194 (  0.048267)

Ruby 3.3.3 on arm64 Macbook M3 pro (on battery):

                           user     system      total        real
OpenStruct slow        4.448626   0.066791   4.515417 (  4.547827)
OpenStruct fast        4.273663   0.033246   4.306909 (  4.323059)
Struct slow            0.236373   0.001003   0.237376 (  0.237390)
Struct fast            0.228933   0.000859   0.229792 (  0.229795)
Hash slow              0.295569   0.001394   0.296963 (  0.296973)
Hash fast              0.265346   0.001351   0.266697 (  0.266701)
Data slow              0.350167   0.001732   0.351899 (  0.351904)
Data fast              0.342578   0.001556   0.344134 (  0.344140)