Ruby constant lookup vs const_get benchmark

const_lookup.rb

Warming up --------------------------------------
              lookup     1.241M i/100ms
           const_get     1.111M i/100ms
Calculating -------------------------------------
              lookup     13.510M (± 0.7%) i/s -    135.305M in  10.031861s
           const_get     11.373M (± 0.5%) i/s -    114.446M in  10.072033s
                   with 95.0% confidence

Comparison:
              lookup: 13509513.8 i/s
           const_get: 11372746.2 i/s - 1.19x  (± 0.01) slower
                   with 95.0% confidence

Source Code:
-----------------------------

# frozen_string_literal: true

require 'benchmark/ips'

# Enable and start GC before each job run. Disable GC afterwards.
#
# Inspired by https://www.omniref.com/ruby/2.2.1/symbols/Benchmark/bm?#annotation=4095926&line=182
class GCSuite
  def warming(*)
    run_gc
  end

  def running(*)
    run_gc
  end

  def warmup_stats(*)
  end

  def add_report(*)
  end

  private

  def run_gc
    GC.enable
    GC.start
    GC.disable
  end
end

GCSuite.new

class Lookup
  def foo
    self.class::Foo
  end
end

class LookupBar < Lookup
  class Foo
  end
end

class ConstGet
  def foo
    self.class.const_get(:Foo)
  end
end

class ConstGetBar < ConstGet
  class Foo
  end
end

l = LookupBar.new
c = ConstGetBar.new

Benchmark.ips do |x|
  x.config(:time => 10, :warmup => 5, :stats => :bootstrap, :confidence => 95)

  x.report('lookup') do
    l.foo
  end

  x.report('const_get') do
    c.foo
  end

  x.compare!
end