Women in Technology

Article:		Untwisting Python Network Programming
Subject:		performance
Date:		2006-08-14 08:16:53
From:		radix
Response to: Why untwisting?
How were these numbers reached? Can you show us any python code or commands that you used to find them? I notice that your synchronous version of the telnet code immediately closes the socket whereas the twisted version is waiting for the *server* to end the connection; this could definitely be affecting your times. If you add a transport.loseConnection call after your write call, the semantics should line up better, and I imagine performance will be closer to what we expect. Also, why are you calling the private "_write" method in the telnet example?

Showing messages 1 through 1 of 1.

• performance
  2006-08-17 04:57:06  Kendrew [View]
  
  
  The time includes starting the interpreter and doing the whole script. It is true that the import statements (and any networking delay) contributes the majority to the execution time in these small programs. In fact, before measuring I did some tidying of the import statements so that only required items are imported before use.
  
  For the telnet, I measure again with the addition of transport.loseConnection() and using StatefulTelnetProtocol instead of Telnet. The Twisted telnet runs faster than before, as expected:
  
  

  
  
  Using core modules:
  
      start server (no net): 0.5809 sec
  
          send mails (smtp): 1.3601 sec
  
          view mails (pop3): 0.7007 sec
  
        delete mails (pop3): 0.5187 sec
  
       stop server (telnet): 0.5124 sec
  
       
  
  Using Twisted:
  
      start server (no net): 0.5959 sec
  
          send mails (smtp): 2.2488 sec
  
          view mails (pop3): 1.4274 sec
  
        delete mails (pop3): 1.3074 sec
  
       stop server (telnet): 1.3213 sec
  
  

  
  
  If you're interested, there is the Python program to measure the timing. It just invokes various usages of the two networking programs and takes the average.
  
  

  
  
  #!/usr/bin/python
  
  # file: mail-timeit.py
  
  # Measures the timing of invoking mail-core.py and mail-twisted.py
  
  
  
  from time import sleep
  
  from timeit import Timer
  
  cmdline = ''
  
  
  
  def doit(cmd, arg, array, rest):
  
      global cmdline
  
      cmdline = cmd + ' ' + arg
  
      print; print cmdline
  
      array.append(Timer('os.system(cmdline)',
  
                  'import os; from __main__ import cmdline').timeit(1))
  
      sleep(rest)
  
      
  
  def dostat(cmd, times):
  
      stat = [[], [], [], [], []] # for 1, s, v, d, 0
  
      
  
      for i in range(times):
  
          doit(cmd, '1', stat[0], 12)
  
          doit(cmd, 's', stat[1], 5)
  
          doit(cmd, 'v', stat[2], 1)
  
          doit(cmd, 'd', stat[3], 1)
  
          doit(cmd, '0', stat[4], 2)
  
  
  
      return stat
  
  
  
  def avgstat(stat, fr, to):
  
      return [ sum(i[fr:to]) / (to-fr) for i in stat ]
  
  
  
  def printavgs(avgs):
  
      labels = [
  
              'start server (no net)', 
  
              'send mails (smtp)',
  
              'view mails (pop3)',
  
              'delete mails (pop3)',
  
              'stop server (telnet)']
  
      for i, j in zip(labels, avgs):
  
          print '%25s: %.4f sec' % (i, j)
  
      
  
  if __name__ == '__main__':
  
      times = 11
  
  
  
      stat1 = dostat('mail-core.py', times)
  
      avgs1 = avgstat(stat1, 1, times)
  
  
  
      stat2 = dostat('mail-twisted.py', times)
  
      avgs2 = avgstat(stat2, 1, times)
  
  
  
      # print stat1
  
      printavgs(avgs1)
  
      # print stat2
  
      printavgs(avgs2)
  
  
  
  # end of mail-timeit.py