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Re: print statements and profiling a function slowed performance

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On Fri, Jun 27, 2014 at 4:35 PM, Ian Kelly <ian.g.kelly@gmail.com> wrote:
> That's got to count for
> something, compared to a raw print that has to wait for the I/O to
> finish.

A raw print basically just tosses some bytes in a stdio buffer (at
least in Unix-land). Stdio does whatever little it does, then passes
the bytes off to the operating system. The underlying OS is then
responsible to see that the bytes get to disk or syslog, or wherever.
It's hard for me to see how that process would be any more time
consuming than the necessary thread switching, followed by what is
essentially the same activity. I haven't looked at the logging module
in awhile (I eventually just rolled my own much simpler version which
only supports what I need), but I don't think it used threads to
perform the actual I/O when it was first written.

Aside... The actual straw that broke the camel's back was that at
work...  One of our C++ programmers wrote a threaded logging module
(to speed up logging by handling it in a thread  - hmmm... sounds
familiar) then wrapped it for use in our Python-based platform. Time
passed, that guy moved on, and I became the sole maintainer of this
particular code base. Finally tired of our applications deadlocking at
inopportune times, I tossed out the threaded stuff and rewrote just
the small bit of the logging module's features I needed in Python. No
performance hit. No deadlocks.

threading-doesn't-always-speed-things-up-ly, y'rs,

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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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