Message 315412 - Python tracker

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Author	serhiy.storchaka
Recipients	rhettinger, serhiy.storchaka
Date	2018-04-17.20:32:06
SpamBayes Score	-1.0
Marked as misclassified	Yes
Message-id	<[email protected]>
In-reply-to

Content
Calling PyObject_LengthHint() adds an overhead. It is significant for short sequences. I work on a patch that reduces it. PR 6493 adds the second call of PyObject_LengthHint() and increases the overhead. As for this issue, in-place repeat overallocates too. >>> a = [0]; a *= 10; getsizeof(a) 200 I think it would be better to make it not preallocating. And maybe it would be worth to avoid overallocating if newsize > allocated + allocated/8 or something like.

Calling PyObject_LengthHint() adds an overhead. It is significant for short sequences. I work on a patch that reduces it. PR 6493 adds the second call of PyObject_LengthHint() and increases the overhead.

As for this issue, in-place repeat overallocates too.

>>> a = [0]; a *= 10; getsizeof(a)
200

I think it would be better to make it not preallocating.

And maybe it would be worth to avoid overallocating if newsize > allocated + allocated/8 or something like.

History
Date	User	Action	Args
2018-04-17 20:32:06	serhiy.storchaka	set	recipients: + serhiy.storchaka, rhettinger
2018-04-17 20:32:06	serhiy.storchaka	set	messageid: <[email protected]>
2018-04-17 20:32:06	serhiy.storchaka	link	issue33234 messages
2018-04-17 20:32:06	serhiy.storchaka	create