download_benchmark.rb

require 'thread'
require 'pp'

def download_time(url)
  `curl --silent -w "%{time_total}" --output /dev/null #{url}`.to_f
end

def compare_download_times(urls,opts={})
  tests = opts[:tests] || 1000
  concurrency = opts[:concurrency] || 1

  results = {}
  urls.each { |url| results[url] = [] }

  threads = []
  pending_tests = tests
  tests_per_thread = tests/concurrency
  mutex = Mutex.new
  concurrency.times do |c|
    if c < (concurrency-1)
      current_tests = tests_per_thread
    else
      current_tests = pending_tests
    end
    pending_tests -= current_tests

    threads << Thread.new do
      urls.each do |url|
        current_tests.times do |i|
          time = download_time(url)
          mutex.synchronize do
            results[url] << time
          end
        end
      end
    end
  end
  threads.each(&:join)
  table = []
  results.each do |url,times|
    table << { url: url,times: times, sum: times.reduce(0,&:+),mean: times.reduce(0,&:+)/times.length, tests: times.length }
  end
  table
end

pp(compare_download_times ['https://s3.amazonaws.com/makeitreal/rodri.jpg','http://ricardorojass.github.io/images/avatar-484cbd85.jpg'], tests: 50, concurrency: 15)


# [{:url=>"https://s3.amazonaws.com/makeitreal/rodri.jpg",
#   :times=>
#    [1.479, 1.499, 1.722, 0.804, 0.879, 1.168, 0.948, 1.043, 0.972, 0.837],
#   :sum=>11.350999999999999,
#   :mean=>1.1351,
#   :tests=>10},
#  {:url=>"http://ricardorojass.github.io/images/avatar-484cbd85.jpg",
#   :times=>
#    [0.898, 0.398, 0.385, 0.369, 0.381, 0.392, 0.395, 0.411, 0.384, 0.365],
#   :sum=>4.378,
#   :mean=>0.4378,
#   :tests=>10}]

#
# [{:url=>"https://s3.amazonaws.com/makeitreal/rodri.jpg",
#   :times=>
#    [1.732,...]
#   :sum=>82.97699999999999,
#   :mean=>1.6595399999999998,
#   :tests=>50},
#  {:url=>"http://ricardorojass.github.io/images/avatar-484cbd85.jpg",
#   :times=>
#    [0.964, ...]
#   :sum=>48.01800000000002,
#   :mean=>0.9603600000000004,
#   :tests=>50}]