New submission from Raymond Hettinger: Speed-up frozenset_hash(). Switching to an entry++ style loop instead of set_next() eliminates much of the loop overhead. Removing the key=NULL or key==dummy checks eliminates the unpredictable branches and makes the loop vectorizable. Those benefits outweigh the extra work of doing a multiplication for every row in set table rather than just the non-null, non-dummy entries.
To make sure the overall hash value is unchanged, there are two final clean-up steps to undo the effect of including dummy and null entries. ---------- assignee: serhiy.storchaka components: Interpreter Core files: fashhash_nobranch.diff keywords: patch messages: 247735 nosy: rhettinger, serhiy.storchaka priority: low severity: normal stage: patch review status: open title: Branchless, vectorizable frozen set hash type: performance versions: Python 3.6 Added file: http://bugs.python.org/file40079/fashhash_nobranch.diff _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue24762> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
