Ruby/Rails Performance: OpenURI vs NET:HTTP vs Curb vs Rest-Client

I'm accessing different servers for data and I tried different methods in different classes, using the basic http::net, curb, rest-client and open-uri

(1) How to measure performance in Ruby / Rails in General? (2) Which method do you think is faster?

Sample code from all 4 different methods:

  url = "..."
  begin 
    io_output = open(url, :http_basic_authentication => [@user_id, @user_password])
  rescue => e
    error = e.message #for debugging return this
    return '-'
  else 
    output = io_output.read 

or

require 'net/https'
uri = URI.parse("...")
http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = true 
http.verify_mode = OpenSSL::SSL::VERIFY_PEER 
data = http.get(uri.request_uri) #http request status
res = Net::HTTP.get_response(uri)
puts res.body if res.is_a?(Net::HTTPSuccess)

or

require 'curb'
url = "..."
c = Curl::Easy.new(url) do |curl| 
curl.headers["Content-type"] = "application/json"
curl.headers["Authorization"] = "Token ..."
end
c.perform
puts c.body_str

or

url = "..." 
resource = RestClient::Resource.new(url, 
       :headers => { :Authorization => "Token ...",  
       :content_type => "application/json"})  
 begin 
 output = resource.get
rescue => e
error = e.message #for debugging return this
return '-'
else ...
end 

I get this kind of results with the next benchmark, by retrieving data from Google.

Warming up --------------------------------------
             OpenURI     3.000  i/100ms
           Net::HTTP     3.000  i/100ms
                curb     3.000  i/100ms
         rest_client     3.000  i/100ms
Calculating -------------------------------------
             OpenURI     34.848  (±11.5%) i/s -    687.000  in  20.013469s
           Net::HTTP     35.433  (±14.1%) i/s -    594.000  in  20.006947s
                curb     31.612  (±19.0%) i/s -    465.000  in  20.021108s
         rest_client     34.331  (±11.7%) i/s -    675.000  in  20.044486s

Comparison:
           Net::HTTP:       35.4 i/s
             OpenURI:       34.8 i/s - same-ish: difference falls within error
         rest_client:       34.3 i/s - same-ish: difference falls within error
                curb:       31.6 i/s - same-ish: difference falls within error

And here is a source code of the benchmark

require 'benchmark/ips'
require 'open-uri'
require 'net/http'
require 'curb'
require 'rest-client'

google_uri = URI('http://www.google.com/')
google_uri_string = google_uri.to_s

Benchmark.ips do |x|
  x.config(time: 20, warmup: 10)
  x.report('OpenURI') { open(google_uri_string) }
  x.report('Net::HTTP') { Net::HTTP.get(google_uri) }
  x.report('curb') { Curl.get(google_uri_string) }
  x.report('rest_client') { RestClient.get(google_uri_string) }
  x.compare!
end

ENVIRONMENT:

1. AWS EC2 server
2. Ruby version - 2.5.1p57
3. Gems: curb-0.9.6, rest-client-2.0.2, benchmark-ips-2.7.2

NOTES:

Don't forget to install gems before running this benchmark

gem install curb rest-client benchmark-ips

To get more accurate results run in a stable network environment, like production servers