[jdk17u-dev] Integrated: 8310268: RISC-V: misaligned memory access in String.Compare intrinsic

[Olga Mikhaltsova]

On Fri, 13 Oct 2023 21:24:51 GMT, Olga Mikhaltsova <omikhaltcova at openjdk.org> wrote:

> I'd like to backport JDK-8310268 to jdk17u. This fix is related only to RISC-V.
> 
> The patch applies cleanly.
> 
> Testing: tier1 tests successfully passed on a RISC-V HiFive board with Linux.
> 
> As it's described in the original fix, this performance improvement can be observed by running the StringCompareToDifferentLength benchmark. The results for jdk17u are as follow:
> 
> Before
> 
> Benchmark                                   (delta)  (size)  Mode  Cnt   Score   Error  Units
> StringCompareToDifferentLength.compareToLL        2       7  avgt    9   4.703 ± 0.090  ms/op
> StringCompareToDifferentLength.compareToLL        2       8  avgt    9   4.896 ± 0.059  ms/op
> StringCompareToDifferentLength.compareToLL        2      15  avgt    9  97.280 ± 2.008  ms/op
> StringCompareToDifferentLength.compareToLL        2      24  avgt    9   3.685 ± 0.031  ms/op
> StringCompareToDifferentLength.compareToLL        2      36  avgt    9  97.924 ± 1.230  ms/op
> StringCompareToDifferentLength.compareToLU        2       7  avgt    9  85.896 ± 3.747  ms/op
> StringCompareToDifferentLength.compareToLU        2       8  avgt    9   5.095 ± 0.065  ms/op
> StringCompareToDifferentLength.compareToLU        2      15  avgt    9  87.073 ± 0.639  ms/op
> StringCompareToDifferentLength.compareToLU        2      24  avgt    9   9.631 ± 0.021  ms/op
> StringCompareToDifferentLength.compareToLU        2      36  avgt    9  13.416 ± 0.088  ms/op
> StringCompareToDifferentLength.compareToUL        2       7  avgt    9  86.940 ± 0.923  ms/op
> StringCompareToDifferentLength.compareToUL        2       8  avgt    9   7.155 ± 0.068  ms/op
> StringCompareToDifferentLength.compareToUL        2      15  avgt    9  89.326 ± 0.864  ms/op
> StringCompareToDifferentLength.compareToUL        2      24  avgt    9  11.678 ± 0.104  ms/op
> StringCompareToDifferentLength.compareToUL        2      36  avgt    9  15.966 ± 0.344  ms/op
> StringCompareToDifferentLength.compareToUU        2       7  avgt    9  97.076 ± 0.818  ms/op
> StringCompareToDifferentLength.compareToUU        2       8  avgt    9   3.625 ± 0.035  ms/op
> StringCompareToDifferentLength.compareToUU        2      15  avgt    9  97.576 ± 1.118  ms/op
> StringCompareToDifferentLength.compareToUU        2      24  avgt    9   4.825 ± 0.070  ms/op
> StringCompareToDifferentLength.compareToUU        2      36  avgt    9   6.221 ± 0.035  ms/op
> 
> After
> 
> Benchmark                                   (delta)  (size)  Mode  Cnt   Score   Error  Units
> StringCompareToDifferentLength.compareToLL      ...

This pull request has now been integrated.

Changeset: 80460e38
Author:    Olga Mikhaltsova <omikhaltcova at openjdk.org>
URL:       https://git.openjdk.org/jdk17u-dev/commit/80460e38f3d9dc0198ad55ccde4e304162488cd0
Stats:     145 lines in 4 files changed: 25 ins; 44 del; 76 mod

8310268: RISC-V: misaligned memory access in String.Compare intrinsic

Reviewed-by: vkempik
Backport-of: d6245b6832ccd1da04616e8ba4b90321b2551971

-------------

PR: https://git.openjdk.org/jdk17u-dev/pull/1876