#!/usr/bin/env ruby
require 'benchmark'
require 'socket'
 
ITERATIONS = 100000
REQUEST = " " * 800
REQUEST_SIZE = REQUEST.size
RESPONSE = " " * 5 * 1024
RESPONSE_SIZE = RESPONSE.size
PASSWORD = "x" * 128
PASSWORD_SIZE = PASSWORD.size
 
def start
  benchmark_with_password_checking
  puts ""
  benchmark_without_password_checking
end
 
def benchmark_with_password_checking
  puts "Benchmarking with password checking..."
  parent, child = UNIXSocket.pair
  pid = fork do
    parent.close
    ITERATIONS.times do
      password = child.read(PASSWORD_SIZE)
      if password == PASSWORD
        child.read(REQUEST_SIZE)
        child.write(RESPONSE)
        # This flush here improves performance significantly!
        child.flush
      else
        child.close
        break
      end
    end
  end
  child.close
  
  result = Benchmark.measure do
    ITERATIONS.times do
      parent.write(PASSWORD)
      parent.write(REQUEST)
      parent.flush
      parent.read(RESPONSE_SIZE)
    end
  end
  parent.close
  Process.waitpid(pid)
  puts "User/system/real time: #{result}"
  printf "%.2f messages per second\n", ITERATIONS / result.real
end
 
def benchmark_without_password_checking
  puts "Benchmarking without password checking..."
  parent, child = UNIXSocket.pair
  pid = fork do
    parent.close
    ITERATIONS.times do
      child.read(REQUEST_SIZE)
      child.write(RESPONSE)
      # This flush here improves performance significantly!
      child.flush
    end
  end
  child.close
  
  result = Benchmark.measure do
    ITERATIONS.times do
      parent.write(REQUEST)
      # We do not call flush. For some reason it degrades performance.
      parent.read(RESPONSE_SIZE)
    end
  end
  parent.close
  Process.waitpid(pid)
  puts "Without password checking:"
  puts "User/system/real time: #{result}"
  printf "%.2f messages per second\n", ITERATIONS / result.real
end
 
start