https://github.com/ma2gedev/faraday-encoding/pull/5

profile.rb

# frozen_string_literal: true

require 'bundler/inline'

gemfile(true) do
  source 'https://rubygems.org'
  gem 'benchmark-memory', require: false
end

require 'benchmark'
require 'benchmark/memory'

HASH = {
  frozen: 'test',
  mutable: 'test'.dup
}

ENCODING = 'utf-8'
LOOPS = 500_000

def frozen_conditional
  HASH[:frozen] = 'test'
  HASH[:frozen] = HASH[:frozen].dup if HASH[:frozen].frozen?
  HASH[:frozen].force_encoding(ENCODING)
end

def frozen_non_conditional
  HASH[:frozen] = 'test'
  HASH[:frozen].dup.force_encoding(ENCODING)
end

def mutable_conditional
  HASH[:mutable] = HASH[:mutable].dup if HASH[:mutable].frozen?
  HASH[:mutable].force_encoding(ENCODING)
end

def mutable_non_conditional
  HASH[:mutable].dup.force_encoding(ENCODING)
end

Benchmark.bmbm do |x|
  x.report('frozen - conditional') do
    LOOPS.times do
      frozen_conditional
    end
  end
  x.report('frozen - non-conditional') do
    LOOPS.times do
      frozen_non_conditional
    end
  end
  x.report('mutable - conditional') do
    LOOPS.times do
      mutable_conditional
    end
  end
  x.report('mutable - non-conditional') do
    LOOPS.times do
      mutable_non_conditional
    end
  end
end

Benchmark.memory do |x|
  x.report('frozen - conditional') do
    LOOPS.times do
      frozen_conditional
    end
  end
  x.report('frozen - non-conditional') do
    LOOPS.times do
      frozen_non_conditional
    end
  end
  x.report('mutable - conditional') do
    LOOPS.times do
      mutable_conditional
    end
  end
  x.report('mutable - non-conditional') do
    LOOPS.times do
      mutable_non_conditional
    end
  end
  x.compare!
end

results-cpu

Rehearsal -------------------------------------------------------------
frozen - conditional        0.283732   0.000318   0.284050 (  0.284053)
frozen - non-conditional    0.197853   0.000612   0.198465 (  0.198556)
mutable - conditional       0.092148   0.000082   0.092230 (  0.092258)
mutable - non-conditional   0.159169   0.000099   0.159268 (  0.159304)
---------------------------------------------------- total: 0.734013sec

user     system      total        real
frozen - conditional        0.240769   0.000155   0.240924 (  0.241009)
frozen - non-conditional    0.177855   0.000123   0.177978 (  0.178045)
mutable - conditional       0.093638   0.000108   0.093746 (  0.093857)
mutable - non-conditional   0.153172   0.000057   0.153229 (  0.153260)

results-memory

Calculating -------------------------------------
frozen - conditional    20.000M memsize (    40.000  retained)
                       500.000k objects (     1.000  retained)
                         1.000  strings (     1.000  retained)
frozen - non-conditional
                        20.000M memsize (     0.000  retained)
                       500.000k objects (     0.000  retained)
                         1.000  strings (     0.000  retained)
mutable - conditional
                         0.000  memsize (     0.000  retained)
                         0.000  objects (     0.000  retained)
                         0.000  strings (     0.000  retained)
mutable - non-conditional
                        20.000M memsize (     0.000  retained)
                       500.000k objects (     0.000  retained)
                         1.000  strings (     0.000  retained)

Comparison:
mutable - conditional:          0 allocated
frozen - conditional:   20000000 allocated - Infx more
frozen - non-conditional:   20000000 allocated - Infx more
mutable - non-conditional:   20000000 allocated - Infx more