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Benchmark vectorized `reverse` and `reverse_copy`, use traits, optimize `reverse_copy` tail by AlexGuteniev · Pull Request #5493 · microsoft/STL · GitHub
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Benchmark vectorized reverse and reverse_copy, use traits, optimize reverse_copy tail #5493

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Merged
merged 6 commits into from
May 17, 2025
Merged

Benchmark vectorized reverse and reverse_copy, use traits, optimize reverse_copy tail #5493

merged 6 commits into from
May 17, 2025

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@AlexGuteniev
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⚙️ Changes

  • Add benchmark, I think this is the only remaining vector algorithm without benchmarks.
  • Use traits to make maintaining easier. We are hiding the exact intrinsics, but we no longer pursue SSE2/SSE4.2 distinction, so that's fine.
  • Use AVX2 masked ops to process tail elements. Somehow this only resulted in an improvement for reverse_copy, but not for reverse. Possibly due to overlapping masked stores -- they do overlap, although overlapped part is masked out in at least one of them. (Commit history preserved this attempt).

⏱️ Benchmark results

Benchmark Before After
r<std::uint8_t>/3449 51.9 ns 46.4 ns
r<std::uint8_t>/63 8.69 ns 8.62 ns
r<std::uint8_t>/31 8.82 ns 8.71 ns
r<std::uint8_t>/15 3.29 ns 3.29 ns
r<std::uint8_t>/7 2.44 ns 2.10 ns
r<std::uint16_t>/3449 91.4 ns 94.4 ns
r<std::uint16_t>/63 4.88 ns 4.94 ns
r<std::uint16_t>/31 4.29 ns 3.99 ns
r<std::uint16_t>/15 3.46 ns 3.32 ns
r<std::uint16_t>/7 2.43 ns 2.13 ns
r<std::uint32_t>/3449 171 ns 173 ns
r<std::uint32_t>/63 4.49 ns 4.47 ns
r<std::uint32_t>/31 3.51 ns 3.62 ns
r<std::uint32_t>/15 2.81 ns 2.83 ns
r<std::uint32_t>/7 2.11 ns 2.12 ns
r<std::uint64_t>/3449 348 ns 342 ns
r<std::uint64_t>/63 5.95 ns 5.78 ns
r<std::uint64_t>/31 3.63 ns 3.61 ns
r<std::uint64_t>/15 2.86 ns 2.98 ns
r<std::uint64_t>/7 2.16 ns 2.14 ns
rc<std::uint8_t>/3449 49.0 ns 48.7 ns
rc<std::uint8_t>/63 8.66 ns 3.31 ns
rc<std::uint8_t>/31 8.26 ns 5.20 ns
rc<std::uint8_t>/15 4.31 ns 4.30 ns
rc<std::uint8_t>/7 2.60 ns 2.62 ns
rc<std::uint16_t>/3449 97.8 ns 101 ns
rc<std::uint16_t>/63 4.76 ns 3.39 ns
rc<std::uint16_t>/31 4.04 ns 2.85 ns
rc<std::uint16_t>/15 3.37 ns 3.08 ns
rc<std::uint16_t>/7 2.87 ns 2.84 ns
rc<std::uint32_t>/3449 171 ns 174 ns
rc<std::uint32_t>/63 4.21 ns 3.97 ns
rc<std::uint32_t>/31 3.52 ns 2.62 ns
rc<std::uint32_t>/15 3.27 ns 2.31 ns
rc<std::uint32_t>/7 2.46 ns 2.37 ns
rc<std::uint64_t>/3449 602 ns 603 ns
rc<std::uint64_t>/63 8.50 ns 7.02 ns
rc<std::uint64_t>/31 3.98 ns 4.03 ns
rc<std::uint64_t>/15 3.06 ns 2.84 ns
rc<std::uint64_t>/7 2.65 ns 2.28 ns

@AlexGuteniev AlexGuteniev requested a review from a team as a code owner May 11, 2025 12:01
@github-project-automation github-project-automation bot moved this to Initial Review in STL Code Reviews May 11, 2025
@StephanTLavavej StephanTLavavej added performance Must go faster test Related to test code labels May 11, 2025
@StephanTLavavej StephanTLavavej self-assigned this May 11, 2025
StephanTLavavej
StephanTLavavej reviewed May 15, 2025
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@StephanTLavavej StephanTLavavej removed their assignment May 15, 2025
@StephanTLavavej StephanTLavavej moved this from Initial Review to Ready To Merge in STL Code Reviews May 15, 2025
@StephanTLavavej StephanTLavavej mentioned this pull request May 15, 2025
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@StephanTLavavej StephanTLavavej moved this from Ready To Merge to Merging in STL Code Reviews May 16, 2025
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I'm mirroring this to the MSVC-internal repo - please notify me if any further changes are pushed.

@StephanTLavavej StephanTLavavej merged commit 2ce34fd into microsoft:main May 17, 2025
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@github-project-automation github-project-automation bot moved this from Merging to Done in STL Code Reviews May 17, 2025
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⏱️ 🚀 🐈

@StephanTLavavej StephanTLavavej mentioned this pull request May 17, 2025
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@AlexGuteniev AlexGuteniev deleted the reverse branch May 17, 2025 03:59
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