Benchmarks instance versus singleton methods

bench_01.rb

require 'bundler/inline'

gemfile do
  source 'https://rubygems.org'

  gem 'benchmark-ips', '~> 2.11'
end

class Calc
  def initialize(a, b)
    @a = a
    @b = b
  end

  def add
    @a + @b
  end
end

module Calculator
  def self.add(a, b)
    a + b
  end
end

Benchmark.ips do |x|
  x.config(time: 5, warmup: 2)

  x.report('instance') { Calc.new(1, 2).add; Calc.new(2, 3).add; Calc.new(4, 5).add; Calc.new(6, 7).add; Calc.new(8, 9).add }
  x.report('singleton') { Calculator.add(1, 2); Calculator.add(2, 3); Calculator.add(4, 5); Calculator.add(6, 7); Calculator.add(8, 9) }

  x.compare!
end

# Warming up --------------------------------------
#             instance   169.998k i/100ms
#            singleton   620.519k i/100ms
# Calculating -------------------------------------
#             instance      1.698M (± 0.2%) i/s -      8.500M in   5.006098s
#            singleton      6.220M (± 0.4%) i/s -     31.646M in   5.088116s

# Comparison:
#            singleton:  6219791.8 i/s
#             instance:  1697918.4 i/s - 3.66x  slower

bench_02.rb

# frozen_string_literal: true

require 'bundler/inline'

gemfile do
  source 'https://rubygems.org'

  gem 'benchmark-ips', '~> 2.11'
end

require 'net/https'

class DogPicFetcher
  RANDOM = URI('https://dog.ceo/api/breeds/image/random')

  def fetch = Net::HTTP.get(RANDOM)
end

module FetchDogPic
  RANDOM = URI('https://dog.ceo/api/breeds/image/random')

  def self.random = Net::HTTP.get(RANDOM)
end

Benchmark.ips do |x|
  x.config(time: 5, warmup: 2)

  x.report('instance') { DogPicFetcher.new.fetch }
  x.report('singleton') { FetchDogPic.random }

  x.compare!
end

# Warming up --------------------------------------
#             instance     1.000  i/100ms
#            singleton     1.000  i/100ms
# Calculating -------------------------------------
#             instance      2.756  (±36.3%) i/s -     14.000  in   5.384464s
#            singleton      3.562  (±28.1%) i/s -     17.000  in   5.147226s

# Comparison:
#            singleton:        3.6 i/s
#             instance:        2.8 i/s - same-ish: difference falls within error