Re: threading

From	Marko Rauhamaa <marko@pacujo.net>
Newsgroups	comp.lang.python
Subject	Re: threading
Date	2014-04-09 20:31 +0300
Organization	A noiseless patient Spider
Message-ID	<87k3ayl893.fsf@elektro.pacujo.net> (permalink)
References	(4 earlier) <mailman.8986.1396914468.18130.python-list@python.org> <877g70wg8p.fsf@elektro.pacujo.net> <mailman.9071.1397049831.18130.python-list@python.org> <87lhveobeq.fsf@elektro.pacujo.net> <mailman.9080.1397054818.18130.python-list@python.org>

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"Frank Millman" <frank@chagford.com>:

> I am finding difficulty in understanding the benefit of going async in
> my case. If most requests require a blocking handler, it seems that I
> might as well stick with each request being handled by a thread,
> independent of all other threads.

When the underlying facilities only provide blocking access, you are
forced to use threads (or processes).

One area where asynchronous programming was always the method of choice
is graphical user interfaces. The GUI of an application must always be
responsive to the user and must be prepared to handle any of numerous
stimuli.

Network protocol layers are also usually implemented asynchronously. The
protocol standards read like asynchronous programs so the translation
into executable programs is most natural in the asynchronous style.
Here, too, the networking entities must be ready for different stimuli
in any state, so threads are usually not a good fit.

Kernel programming makes use of threads and processes. However, the
asynchronous style is there in a big way in the form of interrupt
handlers, hooks and system calls.

Really, the threading model is only good for a relatively small subset
of programming objectives, and over the lifetime of the solution, you
will often come to realize threading wasn't that good a fit after all.
Namely, in any given state, you will have to be prepared to handle more
than one stimulus. Also, over time you will learn to dread the race
conditions that are endemic in thread programming. Those are the kinds
of problems that make you check out the current job postings. Only
there's no escape: in your next job, they are going to make you find and
fix the race conditions in your predecessor's code.


Marko

Thread

Re: threading Ben Finney <ben+python@benfinney.id.au> - 2014-04-07 13:05 +1000
  Re: threading Roy Smith <roy@panix.com> - 2014-04-06 23:48 -0400
    Re: threading Chris Angelico <rosuav@gmail.com> - 2014-04-07 13:56 +1000
      Re: threading Roy Smith <roy@panix.com> - 2014-04-07 08:26 -0400
        Re: threading Chris Angelico <rosuav@gmail.com> - 2014-04-07 22:34 +1000
          Re: threading Roy Smith <roy@panix.com> - 2014-04-07 09:22 -0400
            Re: threading Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-04-07 14:41 +0100
            Re: threading Marko Rauhamaa <marko@pacujo.net> - 2014-04-07 16:49 +0300
              Re: threading Chris Angelico <rosuav@gmail.com> - 2014-04-08 00:27 +1000
                Re: threading Marko Rauhamaa <marko@pacujo.net> - 2014-04-07 17:51 +0300
                Re: threading Chris Angelico <rosuav@gmail.com> - 2014-04-08 01:12 +1000
            Re: threading Chris Angelico <rosuav@gmail.com> - 2014-04-08 00:24 +1000
      Re: threading Rick Johnson <rantingrickjohnson@gmail.com> - 2014-04-08 18:09 -0700
        Re: threading "Neil D. Cerutti" <neilc@norwich.edu> - 2014-04-09 09:50 -0400
          Re: threading Rick Johnson <rantingrickjohnson@gmail.com> - 2014-04-09 08:51 -0700
            Re: threading MRAB <python@mrabarnett.plus.com> - 2014-04-09 18:47 +0100
              Re: threading Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-04-10 11:35 +1200
                Re: threading Roy Smith <roy@panix.com> - 2014-04-09 19:53 -0400
                Re: threading Andrew Berg <robotsondrugs@gmail.com> - 2014-04-09 19:02 -0500
                Re: threading Steven D'Aprano <steve@pearwood.info> - 2014-04-10 02:43 +0000
                Re: threading Chris Angelico <rosuav@gmail.com> - 2014-04-10 13:08 +1000
                Re: threading Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-04-10 09:23 +0100
                Re: threading Chris Angelico <rosuav@gmail.com> - 2014-04-10 19:11 +1000
            Re: threading Chris Angelico <rosuav@gmail.com> - 2014-04-10 04:00 +1000
            Re: threading Steven D'Aprano <steve@pearwood.info> - 2014-04-10 03:44 +0000
              Re: threading Chris Angelico <rosuav@gmail.com> - 2014-04-10 13:54 +1000
    Re: threading Ben Finney <ben+python@benfinney.id.au> - 2014-04-07 15:22 +1000
    Re: threading Ethan Furman <ethan@stoneleaf.us> - 2014-04-08 11:09 -0700
    Re: threading Sturla Molden <sturla.molden@gmail.com> - 2014-04-08 21:41 +0200
      Re: threading Grant Edwards <invalid@invalid.invalid> - 2014-04-08 20:30 +0000
        Re: threading Sturla Molden <sturla.molden@gmail.com> - 2014-04-09 00:32 +0200
          Re: threading Rustom Mody <rustompmody@gmail.com> - 2014-04-08 19:17 -0700
  Re: threading Marko Rauhamaa <marko@pacujo.net> - 2014-04-07 08:10 +0300
    Re: threading Paul Rubin <no.email@nospam.invalid> - 2014-04-06 22:39 -0700
      Re: threading Marko Rauhamaa <marko@pacujo.net> - 2014-04-07 08:46 +0300
      Re: threading Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-04-07 19:47 -0400
        Re: threading Marko Rauhamaa <marko@pacujo.net> - 2014-04-08 08:19 +0300
          Re: threading Sturla Molden <sturla.molden@gmail.com> - 2014-04-08 10:47 +0000
            Re: threading Marko Rauhamaa <marko@pacujo.net> - 2014-04-08 15:10 +0300
              Re: threading Sturla Molden <sturla.molden@gmail.com> - 2014-04-08 16:37 +0000
                Re: threading Marko Rauhamaa <marko@pacujo.net> - 2014-04-08 20:17 +0300
            Re: threading Roy Smith <roy@panix.com> - 2014-04-08 09:19 -0400
              Re: threading Sturla Molden <sturla.molden@gmail.com> - 2014-04-08 15:44 +0000
                Re: threading Paul Rubin <no.email@nospam.invalid> - 2014-04-08 09:38 -0700
                Re: threading Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-04-09 14:42 +0100
          Re: threading "Frank Millman" <frank@chagford.com> - 2014-04-09 15:23 +0200
            Re: threading Marko Rauhamaa <marko@pacujo.net> - 2014-04-09 16:55 +0300
              Re: threading "Frank Millman" <frank@chagford.com> - 2014-04-09 16:46 +0200
                Re: threading Marko Rauhamaa <marko@pacujo.net> - 2014-04-09 20:31 +0300
                Re: threading Chris Angelico <rosuav@gmail.com> - 2014-04-10 03:52 +1000
                Re: threading Mark H Harris <harrismh777@gmail.com> - 2014-04-10 08:29 -0500
                Re: threading Sturla Molden <sturla.molden@gmail.com> - 2014-04-09 19:20 +0000
          Re: threading Chris Angelico <rosuav@gmail.com> - 2014-04-09 23:47 +1000
            Re: threading Roy Smith <roy@panix.com> - 2014-04-09 10:44 -0400
          Re: threading "Frank Millman" <frank@chagford.com> - 2014-04-09 16:30 +0200
            Re: threading Roy Smith <roy@panix.com> - 2014-04-09 10:52 -0400
              Re: threading Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-04-10 11:19 +1200
            Re: threading Marko Rauhamaa <marko@pacujo.net> - 2014-04-09 19:48 +0300
          Re: threading Chris Angelico <rosuav@gmail.com> - 2014-04-10 00:44 +1000
          Re: threading Sturla Molden <sturla.molden@gmail.com> - 2014-04-09 15:29 +0000
          Re: threading Terry Reedy <tjreedy@udel.edu> - 2014-04-09 12:14 -0400
          Re: threading Chris Angelico <rosuav@gmail.com> - 2014-04-10 02:25 +1000
          Re: threading Sturla Molden <sturla.molden@gmail.com> - 2014-04-09 16:32 +0000
          Re: threading Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-04-09 19:44 -0400
          Re: threading Chris Angelico <rosuav@gmail.com> - 2014-04-10 11:05 +1000
          Re: threading "Frank Millman" <frank@chagford.com> - 2014-04-10 11:17 +0200
          Re: threading Chris Angelico <rosuav@gmail.com> - 2014-04-10 19:40 +1000
          Re: threading "Frank Millman" <frank@chagford.com> - 2014-04-10 13:10 +0200
            Re: threading Marko Rauhamaa <marko@pacujo.net> - 2014-04-10 14:43 +0300
              Re: threading Roy Smith <roy@panix.com> - 2014-04-10 08:56 -0400
              Re: threading Sturla Molden <sturla.molden@gmail.com> - 2014-04-10 15:24 +0000
                Re: threading Marko Rauhamaa <marko@pacujo.net> - 2014-04-10 19:20 +0300
              Re: threading Chris Angelico <rosuav@gmail.com> - 2014-04-11 01:32 +1000
                Re: threading Marko Rauhamaa <marko@pacujo.net> - 2014-04-10 19:25 +0300
                Re: threading Chris Angelico <rosuav@gmail.com> - 2014-04-11 03:08 +1000
                Re: threading Rustom Mody <rustompmody@gmail.com> - 2014-04-10 11:14 -0700
                Re: threading Marko Rauhamaa <marko@pacujo.net> - 2014-04-10 22:44 +0300
                Re: threading Rustom Mody <rustompmody@gmail.com> - 2014-04-10 13:21 -0700
                Re: threading Marko Rauhamaa <marko@pacujo.net> - 2014-04-10 23:44 +0300
                Re: threading Rustom Mody <rustompmody@gmail.com> - 2014-04-10 22:15 -0700
                Re: threading Rustom Mody <rustompmody@gmail.com> - 2014-04-10 23:50 -0700
                Re: threading Marko Rauhamaa <marko@pacujo.net> - 2014-04-11 18:36 +0300
                Re: threading Chris Angelico <rosuav@gmail.com> - 2014-04-12 01:53 +1000
                Re: threading Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-04-11 16:58 +0100
                Re: threading Rustom Mody <rustompmody@gmail.com> - 2014-04-11 11:54 -0700
                Re: threading Marko Rauhamaa <marko@pacujo.net> - 2014-04-11 22:27 +0300
                Re: threading Sturla Molden <sturla.molden@gmail.com> - 2014-04-11 01:51 +0200
                Re: threading Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-04-11 05:35 +0000
                Re: threading Sturla Molden <sturla.molden@gmail.com> - 2014-04-11 09:26 +0000
                Re: threading Roy Smith <roy@panix.com> - 2014-04-11 08:36 -0400
                Re: threading Grant Edwards <invalid@invalid.invalid> - 2014-04-11 16:18 +0000
                Re: threading Sturla Molden <sturla.molden@gmail.com> - 2014-04-11 02:21 +0200
                Re: threading Terry Reedy <tjreedy@udel.edu> - 2014-04-10 20:23 -0400
          Re: threading Chris Angelico <rosuav@gmail.com> - 2014-04-10 21:19 +1000
      Re: threading Sturla Molden <sturla.molden@gmail.com> - 2014-04-08 02:06 +0000
        Re: threading alister <alister.nospam.ware@ntlworld.com> - 2014-04-08 11:07 +0000
          Re: threading Roy Smith <roy@panix.com> - 2014-04-08 09:13 -0400
            Re: threading Chris Angelico <rosuav@gmail.com> - 2014-04-08 23:23 +1000
              Re: threading alister <alister.nospam.ware@ntlworld.com> - 2014-04-08 14:15 +0000
                Re: threading Sturla Molden <sturla.molden@gmail.com> - 2014-04-08 16:06 +0000
            Re: threading Sturla Molden <sturla.molden@gmail.com> - 2014-04-08 15:40 +0000
              Re: threading Paul Rubin <no.email@nospam.invalid> - 2014-04-08 09:46 -0700
                Re: threading Chris Angelico <rosuav@gmail.com> - 2014-04-09 02:46 +1000
                Re: threading Sturla Molden <sturla.molden@gmail.com> - 2014-04-08 17:17 +0000
          Re: threading Sturla Molden <sturla.molden@gmail.com> - 2014-04-08 15:19 +0000

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