[PATCH] D93233: [libc++] Replaces std::sort by Bitset sorting algorithm.

[MinJae Hwang via Phabricator via llvm-commits]

minjaehwang added a comment.

I worked on performance improvements and wrote a documentation what bitset sort is and why it is faster. Thanks to LLVM's ability to generate SIMD instructions, bitset sort lets LLVM to generate SIMD instructions for the critical path (bitset partition).

The documentation and the newer implementation is here - https://github.com/minjaehwang/bitsetsort. This implementation is faster than pdqsort for all randomized inputs. For example, in the case of uint64 256k set, bitset sort only takes 15ns per element while pdqsort takes 24ns per element.

Bitset sort shows a little regression on patterns such as ascending or descending. This is something I can work on but I do believe that speed-ups in randomized inputs triumphs the regression in these patterns because these are so small in difference.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D93233/new/

https://reviews.llvm.org/D93233