So it looks like both list and tuple are about within 5% of using co_extra directly. Using a tuple instead of a list is about a wash except for make_v2 where list is 1.4x slower for some reason (which I didn't dig into).
I would say that using a tuple and copying the tuple on updates makes sense as we don't expect these to change very often and we don't expect collisions to happen very often. > -----Original Message----- > From: Python-Dev [mailto:python-dev- > bounces+dinov=microsoft....@python.org] On Behalf Of Chris Angelico > Sent: Tuesday, August 30, 2016 2:11 PM > To: python-dev <python-dev@python.org> > Subject: Re: [Python-Dev] Update on PEP 523 and adding a co_extra field to > code objects > > On Wed, Aug 31, 2016 at 4:55 AM, Serhiy Storchaka <storch...@gmail.com> > wrote: > > On 30.08.16 21:20, Antoine Pitrou wrote: > >> > >> On Tue, 30 Aug 2016 18:12:01 +0000 > >> Brett Cannon <br...@python.org> wrote: > >>>> > >>>> Why not make it always a list? List objects are reasonably cheap > >>>> in memory and access time... (unlike dicts) > >>> > >>> > >>> Because I would prefer to avoid any form of unnecessary performance > >>> overhead for the common case. > >> > >> > >> But the performance overhead of iterating over a 1-element list is > >> small enough (it's just an array access after a pointer dereference) > >> that it may not be larger than the overhead of the multiple tests and > >> conditional branches your example shows. > > > > > > Iterating over a tuple is even faster. It needs one pointer > > dereference less. > > > > And for memory efficiency we can use just a raw array of pointers. > > Didn't all this kind of thing come up when function annotations were > discussed? Insane schemes like dictionaries with UUID keys and so on. > The decision then was YAGNI. The decision now, IMO, should be the same. > Keep things simple. > > ChrisA > _______________________________________________ > Python-Dev mailing list > Python-Dev@python.org > https://na01.safelinks.protection.outlook.com/?url=https%3a%2f%2fmail.pyt > hon.org%2fmailman%2flistinfo%2fpython- > dev&data=01%7c01%7cdinov%40microsoft.com%7c9d750b06b2134a2145c70 > 8d3d11a4ab0%7c72f988bf86f141af91ab2d7cd011db47%7c1&sdata=szub1gs > DW2rdns3IQGV68J3tCqWiNcjqG77xYIfoORc%3d > Unsubscribe: > https://na01.safelinks.protection.outlook.com/?url=https%3a%2f%2fmail.pyt > hon.org%2fmailman%2foptions%2fpython- > dev%2fdinov%2540microsoft.com&data=01%7c01%7cdinov%40microsoft.co > m%7c9d750b06b2134a2145c708d3d11a4ab0%7c72f988bf86f141af91ab2d7c > d011db47%7c1&sdata=TEzMSyJLmAe2BVZGPugXAh6bga2xN1WQw3bR0z0b > %2fLg%3d _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
