Message 274233 - Python tracker

Message274233

Author	vstinner
Recipients	benjamin.peterson, ezio.melotti, lemburg, pitrou, serhiy.storchaka, vstinner
Date	2016-09-02.11:38:39
SpamBayes Score	-1.0
Marked as misclassified	Yes
Message-id	<1472816319.38.0.247037755651.issue16334@psf.upfronthosting.co.za>
In-reply-to

Content
Unicode escape encodecs were modified by the issue #25353 to use the _PyBytesWriter API. Sadly, I didn't benchmark my change before pushing it :-/ Your patch basically reverts my change. > Py3.2 Py3.3 Py3.6 Py3.6+patch > 195 (+136%) 109 (+323%) 258 (+79%) 461 encode unicode-escape 'A'10000 > 391 (+1310%) 333 (+1556%) 575 (+859%) 5514 encode raw-unicode-escape 'A'10000 I'm surprised that the revert makes raw-unicode-escape encoder so much faster. Does it mean that the _PyBytesWriter API is so inefficient? The most efficient case for _PyBytesWriter is when you only call _PyBytesWriter_Alloc() and _PyBytesWriter_Finish() and the output string has exactly the allocated length. It should be the case when 'A'*10000 is encoded, no?

Content

Unicode escape encodecs were modified by the issue #25353 to use the _PyBytesWriter API. Sadly, I didn't benchmark my change before pushing it :-/

Your patch basically reverts my change.

> Py3.2        Py3.3        Py3.6        Py3.6+patch
> 195 (+136%)  109 (+323%)  258 (+79%)   461    encode  unicode-escape  'A'*10000
> 391 (+1310%) 333 (+1556%) 575 (+859%)  5514   encode  raw-unicode-escape  'A'*10000

I'm surprised that the revert makes raw-unicode-escape encoder so much faster. Does it mean that the _PyBytesWriter API is so inefficient?

The most efficient case for _PyBytesWriter is when you only call _PyBytesWriter_Alloc() and _PyBytesWriter_Finish() and the output string has exactly the allocated length. It should be the case when 'A'*10000 is encoded, no?

History
Date	User	Action	Args
2016-09-02 11:38:39	vstinner	set	recipients: + vstinner, lemburg, pitrou, benjamin.peterson, ezio.melotti, serhiy.storchaka
2016-09-02 11:38:39	vstinner	set	messageid: <1472816319.38.0.247037755651.issue16334@psf.upfronthosting.co.za>
2016-09-02 11:38:39	vstinner	link	issue16334 messages
2016-09-02 11:38:39	vstinner	create