jruby_atom.rb

#!/usr/bin/env ruby

require 'concurrent'
require 'benchmark'

NUM      = 50_000_000
WARM_UPS = NUM

def jruby?
  defined? JRUBY_VERSION
end

def version
  gem_dir = Gem::Specification.find_by_name('concurrent-ruby').gem_dir
  File.open(File.join(gem_dir, 'VERSION'), 'r').read
rescue
  'unknown'
end

puts "~~~ Ruby version: #{RUBY_VERSION}"
if jruby?
  puts "~~~ JRuby version: #{JRUBY_VERSION}"
else
  puts "~~~ Ruby engine: #{RUBY_ENGINE}"
end
puts "~~~ Gem version: #{version}"

Benchmark.bm do |stats|

  puts "Benchmarking #{Concurrent::Atom}..."

  ref   = Concurrent::Atom.new('foo')
  value = nil

  puts 'Before JVM warm-up...' if jruby?
  stats.report do
    NUM.times { value = ref.value }
  end

  if jruby?
    WARM_UPS.times { value = ref.value }

    puts 'After JVM warm-up...'
    stats.report do
      NUM.times { value = ref.value }
    end
  end
end