Raymond Hettinger added the comment: Serhiy, I've posted a patch so you can examine the effects in detail.
For something like set(range(n)), I would expect no change because the dataset is collision free due to Tim's design where hash(someint)==someint. That said, I'm trying to optimize the general case and don't really if rare cases are modestly slowed. The new code only kicks in when there is a collision. The logic for the initial probe is unchanged. The idea is to pickup some of the cache locality benefits of collision resolution by separate chaining, but not incurring the 100% malloc typically associated with chaining. When adjacent entries are in the same cache-line, the cost of the extra adjacent probe is much cheaper (nearly zero) than a probe somewhere else in memory. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue18771> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
