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Re: print statements and profiling a function slowed performance

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On Thu, 26 Jun 2014 11:44:29 -0700 (PDT), CM <cmpython@gmail.com> declaimed
the following:

>1. print statements were slowing down my code enough to
>really notice a particular transition. It went from about
>2-3 seconds to a bit under 1 second. What at first seemed
>unresponsive now seems almost snappy. The only difference
>was removing a lot of print statements I had used for
>debugging (Python 2.5, on a single core 1.97 Ghz machine).
>
	Lots of I/O will slow anything down -- consider; every I/O operation
will trigger an OS level process swap, since they are synchronous and
handled by the OS.

	Last fall I was collecting data for a number of candidate hardware
platforms (apologies for the vagueness, but I suspect the details would
fall under some sort of proprietary information clause at my place of
employment).

	The biggest finding was that the console (and even disk) logging of
actions* resulted in a large latency in the throughput of those hardware
platforms.

* I'm stretching to reveal that what the platforms were logging were
considered "exceptional" events by the providers, but for our application
would be "normal"; hence we were effectively flooding them with lots of
data that triggered exception processing and associated logging. Data that
didn't trigger the exception could pass with less than 1mSec delay, but
once a batch of exception data arrived the delays grew to 10mSec or more --
mostly as the log I/O was delaying processing of subsequent packets.

-- 
	Wulfraed                 Dennis Lee Bieber         AF6VN
    wlfraed@ix.netcom.com    HTTP://wlfraed.home.netcom.com/

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print statements and profiling a function slowed performance CM <cmpython@gmail.com> - 2014-06-26 11:44 -0700
  Re: print statements and profiling a function slowed performance Michael Torrie <torriem@gmail.com> - 2014-06-26 13:14 -0600
    Re: print statements and profiling a function slowed performance CM <cmpython@gmail.com> - 2014-06-26 13:36 -0700
      Re: print statements and profiling a function slowed performance Chris Angelico <rosuav@gmail.com> - 2014-06-27 12:06 +1000
      Re: print statements and profiling a function slowed performance Michael Torrie <torriem@gmail.com> - 2014-06-26 19:59 -0600
      Re: print statements and profiling a function slowed performance Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-06-28 09:41 -0400
      Re: print statements and profiling a function slowed performance Chris Angelico <rosuav@gmail.com> - 2014-06-28 23:50 +1000
      Re: print statements and profiling a function slowed performance Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-06-29 02:14 -0400
      Re: print statements and profiling a function slowed performance Chris Angelico <rosuav@gmail.com> - 2014-06-29 17:14 +1000
  Re: print statements and profiling a function slowed performance Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-06-26 20:27 +0100
    Re: print statements and profiling a function slowed performance CM <cmpython@gmail.com> - 2014-06-26 13:37 -0700
      Re: print statements and profiling a function slowed performance Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-27 02:55 +0000
        Re: print statements and profiling a function slowed performance Chris Angelico <rosuav@gmail.com> - 2014-06-27 13:14 +1000
        Re: print statements and profiling a function slowed performance Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-06-27 16:55 +0100
        Re: print statements and profiling a function slowed performance Skip Montanaro <skip@pobox.com> - 2014-06-27 11:05 -0500
        Re: print statements and profiling a function slowed performance Ian Kelly <ian.g.kelly@gmail.com> - 2014-06-27 15:35 -0600
        Re: print statements and profiling a function slowed performance Skip Montanaro <skip@pobox.com> - 2014-06-27 19:12 -0500
        Re: print statements and profiling a function slowed performance Chris Angelico <rosuav@gmail.com> - 2014-06-28 10:29 +1000
          Re: print statements and profiling a function slowed performance Marko Rauhamaa <marko@pacujo.net> - 2014-06-28 22:20 +0300
            Re: print statements and profiling a function slowed performance Chris Angelico <rosuav@gmail.com> - 2014-06-29 09:30 +1000
            Re: print statements and profiling a function slowed performance Rustom Mody <rustompmody@gmail.com> - 2014-06-28 19:25 -0700
              Re: print statements and profiling a function slowed performance Chris Angelico <rosuav@gmail.com> - 2014-06-29 12:32 +1000
        Re: print statements and profiling a function slowed performance Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-06-28 02:06 +0100
  Re: print statements and profiling a function slowed performance Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-06-26 22:11 -0400

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