Message 286607 - Python tracker

Message286607

Author	methane
Recipients	christian.heimes, lemburg, methane, rhettinger
Date	2017-02-01.09:50:43
SpamBayes Score	-1.0
Marked as misclassified	Yes
Message-id	<1485942644.07.0.463511504547.issue29410@psf.upfronthosting.co.za>
In-reply-to

Content
> it seems as if it would make sense to not use a fixed > hash algorithm for all strings lengths, but instead a > hybrid one to increase performance for short strings > (which are used a lot in Python). > > Is there a good hash algorithm with provides better > performance for short strings than siphash ? There is undocumented option "Py_HASH_CUTOFF" to use DJBX33A for short string. See https://github.com/python/cpython/blob/master/Include/pyhash.h#L98

Content

> it seems as if it would make sense to not use a fixed
> hash algorithm for all strings lengths, but instead a
> hybrid one to increase performance for short strings
> (which are used a lot in Python).
>
> Is there a good hash algorithm with provides better
> performance for short strings than siphash ?

There is undocumented option "Py_HASH_CUTOFF" to use DJBX33A for short string.

See https://github.com/python/cpython/blob/master/Include/pyhash.h#L98

History
Date	User	Action	Args
2017-02-01 09:50:44	methane	set	recipients: + methane, lemburg, rhettinger, christian.heimes
2017-02-01 09:50:44	methane	set	messageid: <1485942644.07.0.463511504547.issue29410@psf.upfronthosting.co.za>
2017-02-01 09:50:44	methane	link	issue29410 messages
2017-02-01 09:50:43	methane	create