ActiveSupport's HashWithIndifferentAccess access benchmark vs common Ruby Hash

hash_with_indifferent_access_benchmark.rb

#####################
# Ruby Version: 2.1.6
#####################

# gem 'activesupport', '=3.2.22'
# gem 'activesupport', '=4.2.5'

require 'active_support/all'
require 'benchmark/ips'

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

  @hash_with_indifferent_access = ActiveSupport::HashWithIndifferentAccess.new(a: 1)
  @hash                         = Hash[a: 2]

  ######
  # Hash
  ######

  x.report("Common Hash#fetch access") do
    @hash.fetch :a
  end

  x.report("Common Hash#[] access") do
    @hash[:a]
  end

  ###########################
  # HashWithIndifferentAccess
  ###########################

  x.report("HashWithIndifferentAccess#fetch Symbol") do
    @hash_with_indifferent_access.fetch :a
  end

  x.report("HashWithIndifferentAccess#fetch String") do
    @hash_with_indifferent_access.fetch 'a'
  end

  x.report("HashWithIndifferentAccess #[] Symbol") do
    @hash_with_indifferent_access[:a]
  end

  x.report("HashWithIndifferentAccess #[] String") do
    @hash_with_indifferent_access['a']
  end

  #########################################
  # Hash#with_indifferent_access convertion
  #########################################

  x.report("Hash#with_indifferent_access #fetch Symbol") do
    @hash.with_indifferent_access.fetch :a
  end

  x.report("Hash#with_indifferent_access #fetch String") do
    @hash.with_indifferent_access.fetch 'a'
  end

  x.report("Hash#with_indifferent_access #[] Symbol") do
    @hash.with_indifferent_access[:a]
  end

  x.report("Hash#with_indifferent_access #[] String") do
    @hash.with_indifferent_access['a']
  end

  # Compare the iterations per second of the various reports!
  x.compare!
end

results_with_3.2.22.txt

▶ ruby hash_with_indifferent_access_benchmark.rb
Calculating -------------------------------------
Common Hash#fetch access
                        48.573k i/100ms
Common Hash#[] access
                        46.887k i/100ms
HashWithIndifferentAccess#fetch Symbol
                        41.125k i/100ms
HashWithIndifferentAccess#fetch String
                        41.433k i/100ms
HashWithIndifferentAccess #[] Symbol
                        35.580k i/100ms
HashWithIndifferentAccess #[] String
                        46.442k i/100ms
Hash#with_indifferent_access #fetch Symbol
                        22.616k i/100ms
Hash#with_indifferent_access #fetch String
                        21.547k i/100ms
Hash#with_indifferent_access #[] Symbol
                        19.568k i/100ms
Hash#with_indifferent_access #[] String
                        21.981k i/100ms
-------------------------------------------------
Common Hash#fetch access
                          5.751M (±11.7%) i/s -     28.318M
Common Hash#[] access
                          7.998M (±12.2%) i/s -     39.244M
HashWithIndifferentAccess#fetch Symbol
                          2.086M (± 8.4%) i/s -     10.364M
HashWithIndifferentAccess#fetch String
                          2.131M (± 6.5%) i/s -     10.607M
HashWithIndifferentAccess #[] Symbol
                          1.478M (± 8.2%) i/s -      7.365M
HashWithIndifferentAccess #[] String
                          3.846M (± 9.6%) i/s -     19.041M
Hash#with_indifferent_access #fetch Symbol
                        436.058k (± 7.9%) i/s -      2.171M
Hash#with_indifferent_access #fetch String
                        435.556k (± 7.1%) i/s -      2.176M
Hash#with_indifferent_access #[] Symbol
                        407.470k (± 7.2%) i/s -      2.035M
Hash#with_indifferent_access #[] String
                        503.255k (± 7.2%) i/s -      2.506M

Comparison:
Common Hash#[] access:  7997771.0 i/s
Common Hash#fetch access:  5750854.4 i/s - 1.39x slower
HashWithIndifferentAccess #[] String:  3845945.3 i/s - 2.08x slower
HashWithIndifferentAccess#fetch String:  2130717.4 i/s - 3.75x slower
HashWithIndifferentAccess#fetch Symbol:  2085604.3 i/s - 3.83x slower
HashWithIndifferentAccess #[] Symbol:  1478029.7 i/s - 5.41x slower
Hash#with_indifferent_access #[] String:   503255.0 i/s - 15.89x slower
Hash#with_indifferent_access #fetch Symbol:   436057.9 i/s - 18.34x slower
Hash#with_indifferent_access #fetch String:   435555.6 i/s - 18.36x slower
Hash#with_indifferent_access #[] Symbol:   407469.7 i/s - 19.63x slower

results_with_4.2.5.txt

▶ ruby hash_with_indifferent_access_benchmark.rb
Calculating -------------------------------------
Common Hash#fetch access
                        47.253k i/100ms
Common Hash#[] access
                        50.406k i/100ms
HashWithIndifferentAccess#fetch Symbol
                        39.602k i/100ms
HashWithIndifferentAccess#fetch String
                        41.055k i/100ms
HashWithIndifferentAccess #[] Symbol
                        35.924k i/100ms
HashWithIndifferentAccess #[] String
                        44.995k i/100ms
Hash#with_indifferent_access #fetch Symbol
                        19.965k i/100ms
Hash#with_indifferent_access #fetch String
                        19.782k i/100ms
Hash#with_indifferent_access #[] Symbol
                        20.016k i/100ms
Hash#with_indifferent_access #[] String
                        23.079k i/100ms
-------------------------------------------------
Common Hash#fetch access
                          6.053M (±10.4%) i/s -     29.864M
Common Hash#[] access
                          8.306M (±10.1%) i/s -     40.980M
HashWithIndifferentAccess#fetch Symbol
                          1.932M (±12.8%) i/s -      9.465M
HashWithIndifferentAccess#fetch String
                          1.994M (± 7.6%) i/s -      9.935M
HashWithIndifferentAccess #[] Symbol
                          1.422M (± 5.6%) i/s -      7.113M
HashWithIndifferentAccess #[] String
                          3.804M (± 9.7%) i/s -     18.808M
Hash#with_indifferent_access #fetch Symbol
                        410.034k (± 5.4%) i/s -      2.056M
Hash#with_indifferent_access #fetch String
                        414.702k (± 6.3%) i/s -      2.077M
Hash#with_indifferent_access #[] Symbol
                        381.347k (± 5.6%) i/s -      1.902M
Hash#with_indifferent_access #[] String
                        470.877k (± 6.0%) i/s -      2.354M

Comparison:
Common Hash#[] access:  8306261.5 i/s
Common Hash#fetch access:  6053147.2 i/s - 1.37x slower
HashWithIndifferentAccess #[] String:  3803546.0 i/s - 2.18x slower
HashWithIndifferentAccess#fetch String:  1993671.6 i/s - 4.17x slower
HashWithIndifferentAccess#fetch Symbol:  1932004.0 i/s - 4.30x slower
HashWithIndifferentAccess #[] Symbol:  1422367.3 i/s - 5.84x slower
Hash#with_indifferent_access #[] String:   470876.8 i/s - 17.64x slower
Hash#with_indifferent_access #fetch String:   414701.6 i/s - 20.03x slower
Hash#with_indifferent_access #fetch Symbol:   410033.7 i/s - 20.26x slower
Hash#with_indifferent_access #[] Symbol:   381347.2 i/s - 21.78x slower