Ruby lambda benchmark

benchmark.rb

require 'bundler/inline'

gemfile do
  source 'https://rubygems.org'
  gem 'benchmark-ips'
end

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

  CopyStrWithClosure = -> str { -> n { str * n } }

  module CopyStrByNumbers
    def self.call(numbers, str)
      numbers.map { |n| copy(str, n) }
    end

    def self.copy(str, n); str * n; end
  end

  class StrCopier
    def initialize(str)
      @str = str
    end

    def call(numbers)
      numbers.map { |n| copy(@str, n) }
    end

    private def copy(str, n); str * n; end
  end

  STR = 'Ho! '
  NUMBERS = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

  str_copier = StrCopier.new(STR)
  copy_with_closure = CopyStrWithClosure[STR]

  x.report("inline block")    { NUMBERS.map { |n| STR * n } }
  x.report("static method")    { CopyStrByNumbers.call(NUMBERS, STR) }
  x.report("instance method")  { str_copier.call(NUMBERS) }
  x.report("lambda + closure") { NUMBERS.map(&copy_with_closure) }

  x.compare!
end

Warming up --------------------------------------
#     inline block    28.452k i/100ms
#     static method    29.079k i/100ms
#     instance method    28.733k i/100ms
#     lambda + closure    32.472k i/100ms
# Calculating -------------------------------------
#     inline block    315.701k (± 3.3%) i/s -      1.593M in   5.052599s
#     static method    288.457k (± 3.9%) i/s -      1.454M in   5.048551s
#     instance method    290.406k (± 3.0%) i/s -      1.465M in   5.050690s
#     lambda + closure    317.376k (± 4.8%) i/s -      1.591M in   5.025673s

# Comparison:
#     lambda + closure:   317376.1 i/s
#     inline block:   315701.3 i/s - same-ish: difference falls within error
#     instance method:   290406.4 i/s - 1.09x  (± 0.00) slower
#     static method:   288457.2 i/s - 1.10x  (± 0.00) slower


# [Done] exited with code=0 in 28.416 seconds