Message 272891 - Python tracker

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Author	vstinner
Recipients	python-dev, serhiy.storchaka, vstinner, yselivanov, ztane
Date	2016-08-16.22:22:40
SpamBayes Score	-1.0
Marked as misclassified	Yes
Message-id	<1471386160.14.0.569274814256.issue27128@psf.upfronthosting.co.za>
In-reply-to

Content
> 5) Reverted changes in Objects/descrobject.c. They added a regression in > namedtuple attributes access. Oh, I now understand. The change makes "namedtuple.attr" slower. With fastcall-3.patch attached to this issue, the fast path is not taken on this benchmark, and so you loose the removed optimization (tuple cached in the modified descriptor function). In fact, you need the "full" fastcall change to make this attribute lookup faster: https://bugs.python.org/issue26814#msg263999 So yeah, it's better to wait until more changes are merged.

> 5) Reverted changes in Objects/descrobject.c. They added a regression in
> namedtuple attributes access.

Oh, I now understand. The change makes "namedtuple.attr" slower. With fastcall-3.patch attached to this issue, the fast path is not taken on this benchmark, and so you loose the removed optimization (tuple cached in the modified descriptor function).

In fact, you need the "full" fastcall change to make this attribute lookup *faster*:
https://bugs.python.org/issue26814#msg263999

So yeah, it's better to wait until more changes are merged.

History
Date	User	Action	Args
2016-08-16 22:22:40	vstinner	set	recipients: + vstinner, python-dev, serhiy.storchaka, yselivanov, ztane
2016-08-16 22:22:40	vstinner	set	messageid: <1471386160.14.0.569274814256.issue27128@psf.upfronthosting.co.za>
2016-08-16 22:22:40	vstinner	link	issue27128 messages
2016-08-16 22:22:40	vstinner	create