rspec with Stackprof http://blog.kazu69.net/2015/10/20/use-stackprof-improve-performance-of-rspec/

Gemfile

# Gemfile
group :test do
...
  gem 'stackprof'
...
end

ls.sh

ls tmp
stackprof-api-v1-hogescontroller-get-show-capacity-over-returns-capacity-over.dump

profile.sh

bundle exec stackprof tmp/stackprof-*

==================================
  Mode: cpu(2000)
  Samples: 606 (0.00% miss rate)
  GC: 50 (8.25%)
==================================
     TOTAL    (pct)     SAMPLES    (pct)     FRAME
       552  (49.1%)         552  (49.1%)     block in ActiveRecord::ConnectionAdapters::AbstractMysqlAdapter#execute
        88   (7.8%)          88   (7.8%)     block in Logger::LogDevice#write
        25   (2.2%)          21   (1.9%)     ActiveSupport::HashWithIndifferentAccess#update
        18   (1.6%)          18   (1.6%)     ActiveSupport::HashWithIndifferentAccess#convert_value
        16   (1.4%)          16   (1.4%)     block (2 levels) in <class:Array>
        18   (1.6%)          15   (1.3%)     ActiveRecord::Type::DateTime#fallback_string_to_time
        42   (3.7%)          14   (1.2%)     block in ActiveSupport::Dependencies::Loadable#require
        17   (1.5%)          12   (1.1%)     ActiveSupport::TimeZone#parse
        15   (1.3%)          10   (0.9%)     ActiveRecord::LazyAttributeHash#assign_default_value
        10   (0.9%)          10   (0.9%)     Arel::Collectors::Bind#<<
        62   (5.5%)           9   (0.8%)     ActiveRecord::Attribute#value
        32   (2.8%)           9   (0.8%)     block in FactoryGirl::Evaluator.define_attribute
         7   (0.6%)           7   (0.6%)     ActiveRecord::Attribute#initialize
        22   (2.0%)           7   (0.6%)     ActiveRecord::LazyAttributeHash#[]
         6   (0.5%)           6   (0.5%)     block in <top (required)>
         8   (0.7%)           6   (0.5%)     ActiveSupport::TimeWithZone#localtime
        24   (2.1%)           6   (0.5%)     ActiveSupport::HashWithIndifferentAccess#[]=
         6   (0.5%)           6   (0.5%)     ActiveRecord::Type::TimeValue#fast_string_to_time
        49   (4.4%)           5   (0.4%)     ActiveRecord::AttributeMethods::Dirty#store_original_raw_attribute
         5   (0.4%)           5   (0.4%)     ActiveSupport::Logger::SimpleFormatter#call
         5   (0.4%)           5   (0.4%)     ThreadSafe::NonConcurrentCacheBackend#[]
         5   (0.4%)           5   (0.4%)     ActiveRecord::ConnectionAdapters::Mysql2Adapter#each_hash
         4   (0.4%)           4   (0.4%)     block in ActiveSupport::Dependencies#search_for_file
         4   (0.4%)           4   (0.4%)     block in ActiveSupport::HashWithIndifferentAccess#update
       147  (13.1%)           4   (0.4%)     ActiveRecord::AttributeMethods::Dirty#write_attribute
         4   (0.4%)           4   (0.4%)     LolipopAccount#setup_date
         4   (0.4%)           4   (0.4%)     ActiveRecord::Associations#association_instance_get
         7   (0.6%)           4   (0.4%)     FactoryGirl::AttributeList#each
       607  (54.0%)           4   (0.4%)     ActiveSupport::Callbacks#run_callbacks
         4   (0.4%)           4   (0.4%)     block in Arel::InsertManager#insert

run.sh

DEST=stackprof INTERVAL=2000 be rspec spec/controllers/api/v1/account_relocations_controller_spec.rb

spec_helper.rb

RSpec.configure do |config|
...
  config.around(:each) do |example|
    dest = ENV.fetch('DEST', 'stackprof-test-')
    path = Rails.root.join("tmp/#{dest}-#{example.full_description.parameterize}.dump")
    interval = ENV.fetch('INTERVAL', 1000).to_i
    StackProf.run(mode: :cpu, out: path.to_s, interval: interval) do
      example.run
    end
  end
...
end