Mark Dickinson <dicki...@gmail.com> added the comment: Here's an updated patch, that errs on the conservative side:
- rotate instead of shifting, as suggested by Raymond. This costs very little, and I admit to feeling uncomfortable about the possibility of just throwing bits away - explicit check for -1 - special case for sizeof(void *) = 2*sizeof(long) All tests pass with the patch applied. I've left the 'convert to PyLong' code in as a safety net: it's used on platforms where sizeof(void *) > sizeof(long) but sizeof(void *) != 2*sizeof(long). I don't know of any such platforms in current use. Sample timings on 64-bit linux (non-debug trunk build, Core 2 Duo). before: dict creation (selected): 1.18751096725 dict creation (shuffled): 1.21234202385 dict creation: 1.00831198692 set creation (selected): 0.869561910629 set creation (shuffled): 0.867420911789 set creation: 0.77153301239 and after: dict creation (selected): 1.06817317009 dict creation (shuffled): 0.987659931183 dict creation: 0.662216901779 set creation (selected): 0.735805034637 set creation (shuffled): 0.659453868866 set creation: 0.445232152939 Added file: http://bugs.python.org/file13026/pointer_hash2.patch _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue5186> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
