JrJackson vs Active Support vs GSON vs pure json

jr_vs_as_gson_vs_json.rb

require "bundler/inline"

gemfile(true) do
  source "https://rubygems.org"
  gem "benchmark-ips", require: "benchmark/ips"
  gem "jrjackson"
  gem "gson"
  gem "activesupport", require: "active_support/all"
end

require "json"

H = {
  a: {
    b: {
      c: [1,2,3,4,5],
      d: 1.4,
      e: :f,
      g: "abcdfesfgsegsegsegsegsegeges"
    }
  }
}.freeze

Benchmark.ips do |x|
  x.warmup = 20
  x.report("JRjackson") do
    JrJackson::Json.dump(H)
  end
  x.report("AS") do
    H.to_json
  end
  x.report("gson") do
    Gson::Encoder.new.encode(H)
  end
  x.report("json") do
    JSON.generate(H)
  end
  x.compare!
end

__END__
Warming up --------------------------------------
           JRjackson    48.792k i/100ms
                  AS     4.446k i/100ms
                gson    43.213k i/100ms
                json    23.096k i/100ms
Calculating -------------------------------------
            JRjackson    783.292k (± 3.7%) i/s -      3.952M
                   AS     53.123k (± 3.9%) i/s -    266.760k
                 gson    552.541k (± 5.6%) i/s -      2.766M
                 json    277.943k (± 3.8%) i/s -      1.409M

Comparison:
  JRjackson:   783292.4 i/s
       gson:   552541.4 i/s - 1.42x slower
       json:   277943.2 i/s - 2.82x slower
        AS:    53122.6 i/s - 14.75x slower