On Thu, 20 Jul 2023 01:27:41 GMT, Glavo <d...@openjdk.org> wrote: >> The changes to `Arrays.hashCode(Object[])` in JDK-8312164 caused its >> performance is reduced by about 80%. >> >> This PR reverts this change. > >> A similar performance decrease have been discussed here: [#14752 >> (comment)](https://github.com/openjdk/jdk/pull/14752#discussion_r1250888931) >> >> Can you check whether adding `@ForceInline` on `Objects.equals` help with >> JIT? If it helps, then I think adding `@ForceInline` might be a better >> solution. > > I added `@ForceInline` on `Objects.hashCode(Object)`, but the JMH results did > not change.
@Glavo I have created a test case with polymorphic objects in an array: https://github.com/liachmodded/jdk/tree/explore/arrays-hash-poly Can you see if you can produce the same outcome on your patch, and how the existing `Objects.equals` behave on the polymorphicObjects case? Benchmark (size) Mode Cnt Score Error Units ArraysHashCode.objects 1 avgt 15 0.770 ± 0.011 ns/op ArraysHashCode.objects 10 avgt 15 4.704 ± 0.059 ns/op ArraysHashCode.objects 100 avgt 15 54.610 ± 0.384 ns/op ArraysHashCode.objects 10000 avgt 15 6053.742 ± 35.244 ns/op Benchmark (size) Mode Cnt Score Error Units ArraysHashCode.polymorphicObjects 1 avgt 15 0.921 ± 0.069 ns/op ArraysHashCode.polymorphicObjects 10 avgt 15 23.322 ± 1.076 ns/op ArraysHashCode.polymorphicObjects 100 avgt 15 211.325 ± 2.200 ns/op ArraysHashCode.polymorphicObjects 10000 avgt 15 81850.916 ± 2427.661 ns/op ------------- PR Comment: https://git.openjdk.org/jdk/pull/14944#issuecomment-1642998263
