[libcxx-commits] [PATCH] D119385: Use trivial relocation operations in std::vector, by porting D67524 and part of D61761 to work on top of the changes in D114732.

[Devin Jeanpierre via Phabricator via libcxx-commits]

devin.jeanpierre updated this revision to Diff 409751.
devin.jeanpierre added a comment.

Add benchmark. Unfortunately, I've failed to actually run it against clang -- I don't know how to run benchmarks against the (unreleased) version of clang that's in the current git repo, so all I've done is run it locally (against gcc, I think).

I have a superset of this benchmark I ran at work (using the internal version of benchmark), shows a 40% performance improvement for trivially relocatable types when using the current version of clang. For example (using unique_ptr with trivial_abi <https://libcxx.llvm.org//DesignDocs/UniquePtrTrivialAbi.html>):

  name                                                        old cpu/op  new cpu/op  delta                                             
  BM_Vector_Push_Copy<int*>                                   4.11ns ±38%  4.11ns ±44%   -0.05%  (p=0.021 n=2301+2238)             
  BM_Vector_Push_Move<std::shared_ptr<int>>                   13.3ns ±37%   9.1ns ±42%  -31.71%  (p=0.000 n=1678+1483)                  
  BM_Vector_Push_Move<std::unique_ptr<int>>                   7.05ns ±10%  4.36ns ± 8%  -38.11%  (p=0.000 n=1716+1957)  

My expectation is that this benchmark I have added here would also show the same, if only I knew how to run it. :)


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D119385/new/

https://reviews.llvm.org/D119385

Files:
  libcxx/benchmarks/vector_operations.bench.cpp
  libcxx/include/__memory/allocator_traits.h
  libcxx/include/memory
  libcxx/include/type_traits
  libcxx/include/vector
  libcxx/test/libcxx/containers/sequences/vector/insert_trivially_relocatable.pass.cpp
  libcxx/test/libcxx/type_traits/is_trivially_relocatable.pass.cpp
  libcxx/test/libcxx/utilities/meta/meta.unary.prop/is_trivially_relocatable.pass.cpp
  libcxx/test/std/containers/sequences/vector/vector.modifiers/insert_exception_safety.pass.cpp

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