Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.python > #26525

Re: On-topic: alternate Python implementations

Path csiph.com!newsfeed.hal-mli.net!feeder3.hal-mli.net!newsfeed.hal-mli.net!feeder1.hal-mli.net!newsfeed.xs4all.nl!newsfeed6.news.xs4all.nl!xs4all!post.news.xs4all.nl!not-for-mail
Return-Path <python-python-list@m.gmane.org>
X-Original-To python-list@python.org
Delivered-To python-list@mail.python.org
X-Spam-Status OK 0.001
X-Spam-Evidence '*H*': 1.00; '*S*': 0.00; 'argument': 0.04; 'subject:Python': 0.05; 'case.': 0.05; 'cpython': 0.05; 'objects,': 0.07; 'repeated': 0.07; 'python': 0.09; 'received:80.91': 0.09; 'received:80.91.229': 0.09; 'received:gmane.org': 0.09; 'received:list': 0.09; 'runtime': 0.09; 'tuple': 0.09; 'cases': 0.15; 'ecosystem.': 0.16; 'from:addr:behnel.de': 0.16; 'from:addr:stefan_ml': 0.16; 'from:name:stefan behnel': 0.16; 'iteration': 0.16; 'language)': 0.16; 'message-id:@dough.gmane.org': 0.16; 'received:80.91.229.3': 0.16; 'received:plane.gmane.org': 0.16; 'stefan': 0.17; '(or': 0.18; 'code.': 0.20; 'subject:skip:i 10': 0.22; 'paul': 0.24; 'header:In-Reply-To:1': 0.25; 'header:User-Agent:1': 0.26; 'common': 0.26; 'implemented': 0.27; "doesn't": 0.28; 'header:X -Complaints-To:1': 0.28; "d'aprano": 0.29; 'loop,': 0.29; 'signatures': 0.29; 'steven': 0.29; 'writes:': 0.29; 'case,': 0.29; 'saves': 0.30; 'function': 0.30; 'compatible': 0.30; 'code': 0.31; 'file': 0.32; 'quickly': 0.32; 'received:84': 0.32; 'apply,': 0.33; 'function.': 0.33; 'turns': 0.33; 'problem': 0.33; 'to:addr:python-list': 0.33; "can't": 0.34; 'faster': 0.35; 'something': 0.35; 'there': 0.35; 'add': 0.36; 'received:org': 0.36; 'but': 0.36; 'expensive': 0.36; 'optimization': 0.37; 'does': 0.37; 'uses': 0.37; 'being': 0.37; 'subject:: ': 0.38; 'some': 0.38; 'things': 0.38; 'performance': 0.39; 'to:addr:python.org': 0.39; 'called': 0.39; 'where': 0.40; 'subject:-': 0.40; 'header:Received:5': 0.40; 'most': 0.61; 'back': 0.62; 'export': 0.62; 'worth': 0.63; 'offer': 0.65; 'fact,': 0.69; 'unusual': 0.71; 'average.': 0.84; 'exercised': 0.84; 'packing': 0.84; 'received:arcor-ip.net': 0.84; 'received:pools.arcor-ip.net': 0.84; 'ridiculously': 0.84
X-Injected-Via-Gmane http://gmane.org/
To python-list@python.org
From Stefan Behnel <stefan_ml@behnel.de>
Subject Re: On-topic: alternate Python implementations
Date Sun, 05 Aug 2012 07:37:48 +0200
References <501cbdf8$0$29978$c3e8da3$5496439d@news.astraweb.com> <mailman.2924.1344062061.4697.python-list@python.org> <501cff63$0$29978$c3e8da3$5496439d@news.astraweb.com> <mailman.2930.1344079082.4697.python-list@python.org> <7x1ujmabs9.fsf@ruckus.brouhaha.com> <501dc461$0$29978$c3e8da3$5496439d@news.astraweb.com> <7x1ujm9kyu.fsf@ruckus.brouhaha.com>
Mime-Version 1.0
Content-Type text/plain; charset=UTF-8
Content-Transfer-Encoding 7bit
X-Gmane-NNTP-Posting-Host dslb-084-056-051-236.pools.arcor-ip.net
User-Agent Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120714 Thunderbird/14.0
In-Reply-To <7x1ujm9kyu.fsf@ruckus.brouhaha.com>
X-BeenThere python-list@python.org
X-Mailman-Version 2.1.12
Precedence list
List-Id General discussion list for the Python programming language <python-list.python.org>
List-Unsubscribe <http://mail.python.org/mailman/options/python-list>, <mailto:python-list-request@python.org?subject=unsubscribe>
List-Archive <http://mail.python.org/pipermail/python-list>
List-Post <mailto:python-list@python.org>
List-Help <mailto:python-list-request@python.org?subject=help>
List-Subscribe <http://mail.python.org/mailman/listinfo/python-list>, <mailto:python-list-request@python.org?subject=subscribe>
Newsgroups comp.lang.python
Message-ID <mailman.2957.1344145080.4697.python-list@python.org> (permalink)
Lines 29
NNTP-Posting-Host 2001:888:2000:d::a6
X-Trace 1344145080 news.xs4all.nl 6966 [2001:888:2000:d::a6]:60904
X-Complaints-To abuse@xs4all.nl
Xref csiph.com comp.lang.python:26525

Show key headers only | View raw

Paul Rubin, 05.08.2012 03:38:
> Steven D'Aprano writes:
>> Runtime optimizations that target the common case, but fall back to 
>> unoptimized code in the rare cases that the optimization doesn't apply, 
>> offer the opportunity of big speedups for most code at the cost of 
>> trivial slowdowns when you do something unusual.
> 
> The problem is you can't always tell if the unusual case is being
> exercised without an expensive dynamic check, which in some cases must
> be repeated in every iteration of a critical inner loop, even though it
> turns out that the program never actually uses the unusual case.

Cython does a lot of optimistic optimisations. That's where a large part of
that huge C file comes from that Cython generates from even simple Python code.

For example, in CPython, C function calls are so ridiculously faster than
Python function calls that it's worth some effort if it saves you from
packing an argument tuple to call into a Python function. In fact, we've
been thinking about ways to export C signatures from Python function
objects, so that code implemented in C (or a C compatible language) can be
called directly from other code implemented in C. That's very common in the
CPython ecosystem.

There are a lot of simple things that quickly add up into a much better
performance on average.

Stefan

Back to comp.lang.python | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

On-topic: alternate Python implementations Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-04 06:15 +0000
  Re: On-topic: alternate Python implementations Chris Angelico <rosuav@gmail.com> - 2012-08-04 16:34 +1000
    Re: On-topic: alternate Python implementations Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-04 10:54 +0000
      Re: On-topic: alternate Python implementations Stefan Krah <stefan-usenet@bytereef.org> - 2012-08-04 13:18 +0200
        Re: On-topic: alternate Python implementations Paul Rubin <no.email@nospam.invalid> - 2012-08-04 08:59 -0700
          Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-04 18:55 +0200
            Re: On-topic: alternate Python implementations Paul Rubin <no.email@nospam.invalid> - 2012-08-04 11:18 -0700
              Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-04 21:06 +0200
                Re: On-topic: alternate Python implementations Paul Rubin <no.email@nospam.invalid> - 2012-08-04 13:43 -0700
                Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-04 23:24 +0200
              Re: On-topic: alternate Python implementations MRAB <python@mrabarnett.plus.com> - 2012-08-04 20:24 +0100
          Re: On-topic: alternate Python implementations Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-05 00:54 +0000
            Re: On-topic: alternate Python implementations Paul Rubin <no.email@nospam.invalid> - 2012-08-04 18:38 -0700
              Re: On-topic: alternate Python implementations Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-05 02:19 +0000
                Re: On-topic: alternate Python implementations John Nagle <nagle@animats.com> - 2012-08-06 22:57 -0700
              Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-05 07:37 +0200
            Re: On-topic: alternate Python implementations Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-08-04 23:09 -0400
      Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-04 13:32 +0200
  Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-04 08:40 +0200
    Re: On-topic: alternate Python implementations Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-04 07:49 +0000
      Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-04 11:10 +0200
        Re: On-topic: alternate Python implementations Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2012-08-04 14:51 +0200
          Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-04 15:53 +0200
            Re: On-topic: alternate Python implementations Ulrich Eckhardt <ulrich.eckhardt@dominolaser.com> - 2012-08-08 10:29 +0200
          Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-04 16:03 +0200
      Re: On-topic: alternate Python implementations Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-08-04 11:05 +0100
      Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-04 12:59 +0200
      Re: On-topic: alternate Python implementations Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-08-04 19:24 +0100
        Re: On-topic: alternate Python implementations Temia Eszteri <lamialily@cleverpun.com> - 2012-08-04 11:34 -0700
        Re: On-topic: alternate Python implementations Ben Finney <ben+python@benfinney.id.au> - 2012-08-06 01:21 +1000
      Re: On-topic: alternate Python implementations Zero Piraeus <schesis@gmail.com> - 2012-08-04 14:42 -0400
      Re: On-topic: alternate Python implementations Zero Piraeus <schesis@gmail.com> - 2012-08-04 14:56 -0400
      Re: On-topic: alternate Python implementations Ethan Furman <ethan@stoneleaf.us> - 2012-08-05 07:27 -0700
  Re: On-topic: alternate Python implementations Tim Roberts <timr@probo.com> - 2012-08-04 13:07 -0700
  Re: On-topic: alternate Python implementations jwp <james.pye@gmail.com> - 2012-08-04 15:05 -0700
  Re: On-topic: alternate Python implementations Jürgen A. Erhard <jae+python@jaerhard.com> - 2012-08-05 01:25 +0200
  Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-05 07:46 +0200
  Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-05 09:51 +0200
  Re: On-topic: alternate Python implementations Jürgen A. Erhard <jae+python@jaerhard.com> - 2012-08-05 14:28 +0200
  Re: On-topic: alternate Python implementations alex23 <wuwei23@gmail.com> - 2012-08-05 20:40 -0700
    Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-06 08:21 +0200
  Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-06 08:46 +0200
  Alternate Python extensions (was alternate Python implementations) rusi <rustompmody@gmail.com> - 2012-08-06 21:23 -0700
    Re: Alternate Python extensions (was alternate Python implementations) Stefan Behnel <stefan_ml@behnel.de> - 2012-08-07 07:09 +0200

csiph-web