Rakefile

ACCESS_KEY_ID = 'xxx'
SECRET_ACCESS_KEY = 'xxx'

COUNT_OF_REQUETS = 100

task :test do
  ec2 = AWS::EC2.new(access_key_id: ACCESS_KEY_ID, secret_access_key: SECRET_ACCESS_KEY)

  results = ec2.regions.map do |region|
    mean = `ab -c 1 -n #{COUNT_OF_REQUETS} #{region.endpoint}/ping | perl -n -e'/([\\d\\.]+)(?= \\[ms\\] \\(mean\\))/ && print $1'`.to_f
    {name: region.name, mean: mean}
  end

  results.sort { |a, b| a[:mean] <=> b[:mean] }.each do |r|
    puts "[#{r[:name]}]"
    puts r[:mean]
  end
end