[ruby-core:99540] [Ruby master Feature#17109] Eliminate the performance impact of operands' order in array's | and &
From:
andrey.samsonov@...
Date:
2020-08-10 12:27:44 UTC
List:
ruby-core #99540
Issue #17109 has been updated by [email protected] (Andrey Samsonov). > > The order is preserved from the original array. My bad, I missed the comment. In this case, I think the optimisation is not worth a change in the spec. ---------------------------------------- Feature #17109: Eliminate the performance impact of operands' order in array's | and & https://bugs.ruby-lang.org/issues/17109#change-86999 * Author: [email protected] (Andrey Samsonov) * Status: Open * Priority: Normal ---------------------------------------- When I do intersection (`a & b`) or union (`a | b`), usually the array in one position is more likely longer than the one in the other position. I always try to remember in what order I should write `a` and` b` for the best performance. The right answers for current implementation are `longer & shorter` and` longer | shorter`. [Here](https://github.com/kryzhovnik/ruby/commit/3b5923746792db5a73bc80a2cb9fe982d41a9fa3) I suggest to make it simpler and eliminate the difference. Sorry I don't know C. Though I suppose my solution might be too blunt and verbose, I hope it demonstrates the idea. make benchmark ITEM=array_union COMPARE_RUBY=~/.rbenv/versions/2.8.0-dev/bin/ruby | |compare-ruby|built-ruby| |:-------------------------|-----------:|---------:| |small-& | 4.315M| 4.228M| | | 1.02x| -| |small-intersection | 4.157M| 4.106M| | | 1.01x| -| |big-& | 107.258k| 132.051k| | | -| 1.23x| |big-intersection | 103.245k| 128.052k| | | -| 1.24x| |big-reverse-intersection | 96.544k| 159.201k| | | -| 1.65x| My own [test](https://gist.github.com/kryzhovnik/288953a5c89df10e2611668703a1511c) shows 20-30% perf improvement of Array#union. -- https://bugs.ruby-lang.org/ Unsubscribe: <mailto:[email protected]?subject=unsubscribe> <http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>