[DEPRECATED] Take a look at https://github.com/okuramasafumi/alba/blob/master/benchmark/local.rb

benchmark.rb

require "bundler/setup"
require "active_record"
require "logger"
require "oj"

ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")
# ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :posts, force: true do |t|
    t.string :body
  end

  create_table :comments, force: true do |t|
    t.integer :post_id
    t.string :body
    t.integer :commenter_id
  end

  create_table :users, force: true do |t|
    t.string :name
  end
end

class Post < ActiveRecord::Base
  has_many :comments
  has_many :commenters, through: :comments, class_name: 'User', source: :commenter

  def attributes
    {id: nil, body: nil, commenter_names: commenter_names}
  end

  def commenter_names
    commenters.pluck(:name)
  end
end

class Comment < ActiveRecord::Base
  belongs_to :post
  belongs_to :commenter, class_name: 'User'

  def attributes
    {id: nil, body: nil}
  end
end

class User < ActiveRecord::Base
  has_many :comments
end

require "alba"
Alba.backend = :oj

class AlbaCommentResource
  include ::Alba::Resource
  attributes :id, :body
end

class AlbaPostResource
  include ::Alba::Resource
  attributes :id, :body
  many :comments, resource: AlbaCommentResource
  attribute :commenter_names do
    commenters.pluck(:name)
  end
end

require "jbuilder"
class Post
  def to_builder
    Jbuilder.new do |post|
      post.call(self, :id, :body, :comments, :commenter_names)
    end
  end

  def commenter_names
    commenters.pluck(:name)
  end
end

class Comment
  def to_builder
    Jbuilder.new do |comment|
      comment.call(self, :id, :body)
    end
  end
end

require "fast_jsonapi"
class FastCommentSerializer
  include FastJsonapi::ObjectSerializer
  attributes :id, :body
end

class FastPostSerializer
  include FastJsonapi::ObjectSerializer
  attributes :id, :body
  attribute :commenter_names do |object|
    object.commenters.pluck(:name)
  end
  has_many :comments, serializer: FastCommentSerializer
end

require "active_model_serializers"

class AMSCommentSerializer < ActiveModel::Serializer
  attributes :id, :body
end

class AMSPostSerializer < ActiveModel::Serializer
  attributes :id, :body
  has_many :comments, serializer: AMSCommentSerializer
  attribute :commenter_names
  def commenter_names
    object.commenters.pluck(:name)
  end
end

require "blueprinter"

class CommentBlueprint < Blueprinter::Base
  fields :id, :body
end

class PostBlueprint < Blueprinter::Base
  fields :id, :body, :commenter_names
  association :comments, blueprint: CommentBlueprint
  def commenter_names
    commenters.pluck(:name)
  end
end

require "jsonapi"
require "jsonapi/renderer"
require "jsonapi/serializable"

class SerializablePost < JSONAPI::Serializable::Resource
  type 'posts'
  attributes :id, :body
  attribute :commenter_names do
    @object.commenters.pluck(:name)
  end
  has_many :comments do
    attributes :data, :body
  end
end

# require "jsonapi-resources"
# class PostResource < JSONAPI::Resource
#   attributes :id, :body
#   attribute :commenter_names do
#     @object.commenters.pluck(:name)
#   end
#   has_many :comments do
#     attributes :data, :body
#   end
# end

require "representable"

class CommentRepresenter < Representable::Decorator
  include Representable::JSON

  property :id
  property :body
end

class PostRepresenter < Representable::Decorator
  include Representable::JSON

  property :id
  property :body
  property :commenter_names
  collection :comments

  def commenter_names
    commenters.pluck(:name)
  end
end

post = Post.create!(body: 'post')
user1 = User.create!(name: 'John')
user2 = User.create!(name: 'Jane')
post.comments.create!(commenter: user1, body: 'Comment1')
post.comments.create!(commenter: user2, body: 'Comment2')
post.reload

alba = Proc.new { AlbaPostResource.new(post).serialize }
jbuilder = Proc.new { post.to_builder.target! }
fast_jsonapi = Proc.new { ActiveSupport::JSON.encode(FastPostSerializer.new(post).serializable_hash) }
ams = Proc.new { AMSPostSerializer.new(post, {}).to_json }
rails = Proc.new { ActiveSupport::JSON.encode(post.serializable_hash(include: :comments)) }
blueprinter = Proc.new { PostBlueprint.render(post) }
jsonapi = Proc.new do
  # Doesn't work
  # renderer = JSONAPI::Serializable::Renderer.new
  # renderer.render(post, class: {Post: SerializablePost})
end
representable = Proc.new { PostRepresenter.new(post).to_json }
alba_inline = Proc.new do
  Alba.serialize(post) do
    attributes :id, :body
    attribute :commenter_names do
      commenters.pluck(:name)
    end
    many :comments do
      attributes :id, :body
    end
  end
end
[alba, jbuilder, fast_jsonapi, ams, rails, blueprinter, jsonapi, representable, alba_inline].each {|x| puts x.call }

require 'benchmark'
time = 10000
Benchmark.bmbm do |x|
  x.report(:alba) { time.times(&alba) }
  x.report(:jbuilder) { time.times(&jbuilder) }
  x.report(:fast_jsonapi) { time.times(&fast_jsonapi) }
  x.report(:ams) { time.times(&ams) }
  x.report(:rails) { time.times(&rails) }
  x.report(:blueprinter) { time.times(&blueprinter) }
  x.report(:representable) { time.times(&representable) }
  x.report(:alba_inline) { time.times(&alba_inline) }
end

Gemfile

# frozen_string_literal: true

source "https://rubygems.org"

git_source(:github) {|repo_name| "https://github.com/#{repo_name}" }

gem "rails"
gem "sqlite3"
gem "jbuilder"
gem "active_model_serializers"
gem "fast_jsonapi"
gem "jsonapi"
gem "jsonapi-serializable"
gem "jsonapi-resources"
gem "blueprinter"
gem "representable"
gem "jsonapi-serializer"
gem "alba"
gem "ruby-prof"
gem "oj"
gem "multi_json"

Gemfile.lock

GEM
  remote: https://rubygems.org/
  specs:
    actioncable (6.0.3.2)
      actionpack (= 6.0.3.2)
      nio4r (~> 2.0)
      websocket-driver (>= 0.6.1)
    actionmailbox (6.0.3.2)
      actionpack (= 6.0.3.2)
      activejob (= 6.0.3.2)
      activerecord (= 6.0.3.2)
      activestorage (= 6.0.3.2)
      activesupport (= 6.0.3.2)
      mail (>= 2.7.1)
    actionmailer (6.0.3.2)
      actionpack (= 6.0.3.2)
      actionview (= 6.0.3.2)
      activejob (= 6.0.3.2)
      mail (~> 2.5, >= 2.5.4)
      rails-dom-testing (~> 2.0)
    actionpack (6.0.3.2)
      actionview (= 6.0.3.2)
      activesupport (= 6.0.3.2)
      rack (~> 2.0, >= 2.0.8)
      rack-test (>= 0.6.3)
      rails-dom-testing (~> 2.0)
      rails-html-sanitizer (~> 1.0, >= 1.2.0)
    actiontext (6.0.3.2)
      actionpack (= 6.0.3.2)
      activerecord (= 6.0.3.2)
      activestorage (= 6.0.3.2)
      activesupport (= 6.0.3.2)
      nokogiri (>= 1.8.5)
    actionview (6.0.3.2)
      activesupport (= 6.0.3.2)
      builder (~> 3.1)
      erubi (~> 1.4)
      rails-dom-testing (~> 2.0)
      rails-html-sanitizer (~> 1.1, >= 1.2.0)
    active_model_serializers (0.10.10)
      actionpack (>= 4.1, < 6.1)
      activemodel (>= 4.1, < 6.1)
      case_transform (>= 0.2)
      jsonapi-renderer (>= 0.1.1.beta1, < 0.3)
    activejob (6.0.3.2)
      activesupport (= 6.0.3.2)
      globalid (>= 0.3.6)
    activemodel (6.0.3.2)
      activesupport (= 6.0.3.2)
    activerecord (6.0.3.2)
      activemodel (= 6.0.3.2)
      activesupport (= 6.0.3.2)
    activestorage (6.0.3.2)
      actionpack (= 6.0.3.2)
      activejob (= 6.0.3.2)
      activerecord (= 6.0.3.2)
      marcel (~> 0.3.1)
    activesupport (6.0.3.2)
      concurrent-ruby (~> 1.0, >= 1.0.2)
      i18n (>= 0.7, < 2)
      minitest (~> 5.1)
      tzinfo (~> 1.1)
      zeitwerk (~> 2.2, >= 2.2.2)
    alba (0.5.0)
    blueprinter (0.25.0)
    builder (3.2.4)
    case_transform (0.2)
      activesupport
    concurrent-ruby (1.1.6)
    crass (1.0.6)
    declarative (0.0.20)
    declarative-option (0.1.0)
    erubi (1.9.0)
    fast_jsonapi (1.5)
      activesupport (>= 4.2)
    globalid (0.4.2)
      activesupport (>= 4.2.0)
    i18n (1.8.5)
      concurrent-ruby (~> 1.0)
    jbuilder (2.10.0)
      activesupport (>= 5.0.0)
    jsonapi (0.1.1.beta6)
      jsonapi-parser (= 0.1.1.beta3)
      jsonapi-renderer (= 0.1.1.beta1)
    jsonapi-parser (0.1.1.beta3)
    jsonapi-renderer (0.1.1.beta1)
    jsonapi-resources (0.10.2)
      activerecord (>= 4.1)
      concurrent-ruby
      railties (>= 4.1)
    jsonapi-serializable (0.1.3)
      jsonapi-renderer (~> 0.1)
    jsonapi-serializer (2.0.0)
      activesupport (>= 4.2)
    loofah (2.6.0)
      crass (~> 1.0.2)
      nokogiri (>= 1.5.9)
    mail (2.7.1)
      mini_mime (>= 0.1.1)
    marcel (0.3.3)
      mimemagic (~> 0.3.2)
    method_source (1.0.0)
    mimemagic (0.3.5)
    mini_mime (1.0.2)
    mini_portile2 (2.4.0)
    minitest (5.14.1)
    multi_json (1.15.0)
    nio4r (2.5.2)
    nokogiri (1.10.10)
      mini_portile2 (~> 2.4.0)
    oj (3.10.8)
    rack (2.2.3)
    rack-test (1.1.0)
      rack (>= 1.0, < 3)
    rails (6.0.3.2)
      actioncable (= 6.0.3.2)
      actionmailbox (= 6.0.3.2)
      actionmailer (= 6.0.3.2)
      actionpack (= 6.0.3.2)
      actiontext (= 6.0.3.2)
      actionview (= 6.0.3.2)
      activejob (= 6.0.3.2)
      activemodel (= 6.0.3.2)
      activerecord (= 6.0.3.2)
      activestorage (= 6.0.3.2)
      activesupport (= 6.0.3.2)
      bundler (>= 1.3.0)
      railties (= 6.0.3.2)
      sprockets-rails (>= 2.0.0)
    rails-dom-testing (2.0.3)
      activesupport (>= 4.2.0)
      nokogiri (>= 1.6)
    rails-html-sanitizer (1.3.0)
      loofah (~> 2.3)
    railties (6.0.3.2)
      actionpack (= 6.0.3.2)
      activesupport (= 6.0.3.2)
      method_source
      rake (>= 0.8.7)
      thor (>= 0.20.3, < 2.0)
    rake (13.0.1)
    representable (3.0.4)
      declarative (< 0.1.0)
      declarative-option (< 0.2.0)
      uber (< 0.2.0)
    ruby-prof (1.4.1)
    sprockets (4.0.2)
      concurrent-ruby (~> 1.0)
      rack (> 1, < 3)
    sprockets-rails (3.2.1)
      actionpack (>= 4.0)
      activesupport (>= 4.0)
      sprockets (>= 3.0.0)
    sqlite3 (1.4.2)
    thor (1.0.1)
    thread_safe (0.3.6)
    tzinfo (1.2.7)
      thread_safe (~> 0.1)
    uber (0.1.0)
    websocket-driver (0.7.3)
      websocket-extensions (>= 0.1.0)
    websocket-extensions (0.1.5)
    zeitwerk (2.4.0)

PLATFORMS
  ruby

DEPENDENCIES
  active_model_serializers
  alba
  blueprinter
  fast_jsonapi
  jbuilder
  jsonapi
  jsonapi-resources
  jsonapi-serializable
  jsonapi-serializer
  multi_json
  oj
  rails
  representable
  ruby-prof
  sqlite3

BUNDLED WITH
   2.1.4

Result

                    user     system      total        real
alba            2.820060   0.022638   2.842698 (  2.895920)
jbuilder        3.771705   0.034647   3.806352 (  3.901307)
fast_jsonapi    4.239389   0.041856   4.281245 (  4.393856)
ams             4.844297   0.049414   4.893711 (  5.092888)
rails           6.527143   0.065684   6.592827 (  6.759237)
blueprinter     3.641437   0.036881   3.678318 (  3.813814)
representable   4.165615   0.040480   4.206095 (  4.318423)
alba_inline     4.100987   0.039418   4.140405 (  4.300006)

correct link to benchmark https://github.com/okuramasafumi/alba/tree/main/benchmark/collection.rb