Path: csiph.com!x330-a1.tempe.blueboxinc.net!usenet.pasdenom.info!aioe.org!news.stack.nl!newsfeed.xs4all.nl!newsfeed6.news.xs4all.nl!xs4all!post.news.xs4all.nl!not-for-mail Return-Path: X-Original-To: python-list@python.org Delivered-To: python-list@mail.python.org X-Spam-Status: OK 0.002 X-Spam-Evidence: '*H*': 1.00; '*S*': 0.00; 'help?': 0.03; 'cpython': 0.05; 'suppose': 0.05; 'sure.': 0.05; 'compiler': 0.07; 'interpreter': 0.07; 'python': 0.08; 'dict': 0.09; 'global,': 0.09; 'interpreter,': 0.09; 'namespace': 0.09; 'wrote:': 0.15; 'ideas?': 0.16; 'len': 0.16; 'lookup': 0.16; 'lot;': 0.16; 'received:192.168.1.40': 0.16; 'subject:Early': 0.16; 'object,': 0.16; 'pm,': 0.16; 'aug': 0.19; 'operations.': 0.19; '(which': 0.20; 'header:In-Reply-To:1': 0.22; 'assume': 0.23; 'uses.': 0.23; 'tue,': 0.23; 'modules': 0.25; 'string': 0.26; 'function': 0.26; 'replaced': 0.29; 'object': 0.30; "it'd": 0.30; 'chris': 0.32; 'done,': 0.32; 'does': 0.32; 'it.': 0.33; 'actually': 0.33; 'to:addr:python-list': 0.34; 'header:User-Agent:1': 0.34; 'normally': 0.34; "isn't": 0.35; 'actual': 0.35; 'some': 0.37; 'doing': 0.37; 'but': 0.37; 'could': 0.37; 'received:192': 0.38; 'takes': 0.38; 'subject:: ': 0.38; 'run': 0.39; 'received:192.168.1': 0.39; 'help': 0.39; 'either': 0.39; "there's": 0.39; 'to:addr:python.org': 0.39; 'called': 0.40; 'where': 0.40; 'kind': 0.60; 'address': 0.61; 'direct': 0.66; 'straight': 0.66; 'received:62': 0.67; 'profile': 0.71; 'introduce': 0.79; "(don't": 0.84; 'from:addr:t': 0.84; 'lookup,': 0.84; 'profiling': 0.84; 'significant.': 0.84 Date: Tue, 02 Aug 2011 20:10:15 +0200 From: Thomas Jollans User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:5.0) Gecko/20110628 Thunderbird/5.0 MIME-Version: 1.0 To: python-list@python.org Subject: Re: Early binding as an option References: <4E38315C.1000102@jollybox.de> In-Reply-To: X-Enigmail-Version: 1.2 OpenPGP: id=5C8691ED Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: General discussion list for the Python programming language List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Newsgroups: comp.lang.python Message-ID: Lines: 27 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1312308603 news.xs4all.nl 23923 [2001:888:2000:d::a6]:38053 X-Complaints-To: abuse@xs4all.nl Xref: x330-a1.tempe.blueboxinc.net comp.lang.python:10755 On 02/08/11 19:42, Chris Angelico wrote: > On Tue, Aug 2, 2011 at 6:18 PM, Thomas Jollans wrote: >> I suppose it would be possible to introduce a kind of "constant >> globals" namespace that a JIT compiler could then use to optimise, but >> how much would this help? > > Surely it must help a lot; looking up names is string operations. If > "len" could be replaced with "@10794928" where 10794928 is the actual > address of the len object, then it'd be doing no work that isn't > normally done, and would go straight to the object and call it. > > But I don't really know how to go about profiling this to be sure. Any ideas? Well, you could run a direct comparison of one function where len is global, and an identitical function where len is local (which does not do a dict lookup, am I right?) Of course the global dict lookup takes time, but I doubt that many modules look up the same name often enough for it to actually be significant. I don't really know enough about either profiling or the CPython interpreter, but I assume there's some function that's called to look up globals; you could profile the Python interpreter (don't ask me with which tool) and see how much time that function uses. Thomas