RFR: 8352075: Perf regression accessing fields [v4]

[Hannes Greule]

On Mon, 5 May 2025 13:57:10 GMT, Radim Vansa <rvansa at openjdk.org> wrote:

> How does the order of iteration cooperate with `@Contended`, though? In `FieldLayoutBuilder::regular_field_sorting` we separate static and contended fields; doesn't that break the requirement?

Hm, I'm not familiar enough with the code there. There seem to be some rather basic tests here https://github.com/openjdk/jdk/tree/1501a5e41e59162a374cf5b8cfc37faced48a6ed/test/hotspot/jtreg/serviceability/jvmti/GetClassFields and here https://github.com/openjdk/jdk/tree/1501a5e41e59162a374cf5b8cfc37faced48a6ed/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassFields (I think https://github.com/openjdk/jdk/blob/1501a5e41e59162a374cf5b8cfc37faced48a6ed/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GetClassFields/getclfld007/getclfld007.cpp#L129 actually tests the order), but nothing with `@Contended` involved. Maybe it is worth to expand the test coverage first?

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PR Comment: https://git.openjdk.org/jdk/pull/24847#issuecomment-2851151806