RFR: 8322770: Implement C2 VectorizedHashCode on AArch64 [v20]
Mikhail Ablakatov
duke at openjdk.org
Fri Sep 27 12:45:58 UTC 2024
> Hello,
>
> Please review the following PR for [JDK-8322770 Implement C2 VectorizedHashCode on AArch64](https://bugs.openjdk.org/browse/JDK-8322770). It follows previous work done in https://github.com/openjdk/jdk/pull/16629 and https://github.com/openjdk/jdk/pull/10847 for RISC-V and x86 respectively.
>
> The code to calculate a hash code consists of two parts: a vectorized loop of Neon instruction that process 4 or 8 elements per iteration depending on the data type and a fully unrolled scalar "loop" that processes up to 7 tail elements.
>
> At the time of writing this I don't see potential benefits from providing SVE/SVE2 implementation, but it could be added as a follow-up or independently later if required.
>
> # Performance
>
> ## Neoverse N1
>
>
> --------------------------------------------------------------------------------------------
> Version Baseline This patch
> --------------------------------------------------------------------------------------------
> Benchmark (size) Mode Cnt Score Error Score Error Units
> --------------------------------------------------------------------------------------------
> ArraysHashCode.bytes 1 avgt 15 1.249 ? 0.060 1.247 ? 0.062 ns/op
> ArraysHashCode.bytes 10 avgt 15 8.754 ? 0.028 4.387 ? 0.015 ns/op
> ArraysHashCode.bytes 100 avgt 15 98.596 ? 0.051 26.655 ? 0.097 ns/op
> ArraysHashCode.bytes 10000 avgt 15 10150.578 ? 1.352 2649.962 ? 216.744 ns/op
> ArraysHashCode.chars 1 avgt 15 1.286 ? 0.062 1.246 ? 0.054 ns/op
> ArraysHashCode.chars 10 avgt 15 8.731 ? 0.002 5.344 ? 0.003 ns/op
> ArraysHashCode.chars 100 avgt 15 98.632 ? 0.048 23.023 ? 0.142 ns/op
> ArraysHashCode.chars 10000 avgt 15 10150.658 ? 3.374 2410.504 ? 8.872 ns/op
> ArraysHashCode.ints 1 avgt 15 1.189 ? 0.005 1.187 ? 0.001 ns/op
> ArraysHashCode.ints 10 avgt 15 8.730 ? 0.002 5.676 ? 0.001 ns/op
> ArraysHashCode.ints 100 avgt 15 98.559 ? 0.016 24.378 ? 0.006 ns/op
> ArraysHashCode.ints 10000 avgt 15 10148.752 ? 1.336 2419.015 ? 0.492 ns/op
> ArraysHashCode.multibytes 1 avgt 15 1.037 ? 0.001 1.037 ? 0.001 ns/op
> ArraysHashCode.multibytes 10 avgt 15 5.4...
Mikhail Ablakatov has updated the pull request incrementally with one additional commit since the last revision:
fixup: use xaddwv2 where required in unit tests
-------------
Changes:
- all: https://git.openjdk.org/jdk/pull/18487/files
- new: https://git.openjdk.org/jdk/pull/18487/files/b55d4baa..7d1c6b77
Webrevs:
- full: https://webrevs.openjdk.org/?repo=jdk&pr=18487&range=19
- incr: https://webrevs.openjdk.org/?repo=jdk&pr=18487&range=18-19
Stats: 12 lines in 2 files changed: 0 ins; 0 del; 12 mod
Patch: https://git.openjdk.org/jdk/pull/18487.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/18487/head:pull/18487
PR: https://git.openjdk.org/jdk/pull/18487
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