[lilliput-jdk17u:lilliput] Integrated: 8310156: [Lilliput/JDK17] Specialize full-GC loops

[Roman Kennke]

On Thu, 15 Jun 2023 15:59:34 GMT, Roman Kennke <rkennke at openjdk.org> wrote:

> We already ported most of [JDK-8305896](https://bugs.openjdk.org/browse/JDK-8305896) to Lilliput/JDK17. What's missing is the specialization of the full-GC loops so that performance on the legacy path is not impacted and performance on the alt-GC-forwarding path is minimized.
> 
> This corresponds to: https://github.com/openjdk/jdk/pull/13582/commits/6bbd29525b2864be37d96750ddc78f73d8eb0b65
> 
> However, the changes differ significantly:
> - G1 serial compaction is different
> - There is no humongous compaction in JDK17 G1
> - Serial GC has seen some refactors of the relevant loops between JDK17 and JDK22
> 
> I see failing tests with Shenandoah, but they are pre-existing and should be investigated separately.
> 
> Testing:
>  - [x] hotspot_gc
>  - [x] hotspot_gc -UCOH
>  - [x] tier1 -XX:+UseG1GC
>  - [x] tier1 -XX:+UseSerialGC
>  - [x] tier1 -XX:+UseShenandoahGC (not clean, but no regressions, either)
>  - [x] tier1 -XX:+UseG1GC -UCOH
>  - [x] tier1 -XX:+UseSerialGC -UCOH
>  - [x] tier1 -XX:+UseShenandoahGC -UCOH (not clean, but no regressions, either)

This pull request has now been integrated.

Changeset: eee9bfe1
Author:    Roman Kennke <rkennke at openjdk.org>
URL:       https://git.openjdk.org/lilliput-jdk17u/commit/eee9bfe1f2ebdb2627907fa63a2c239da3aff533
Stats:     316 lines in 24 files changed: 204 ins; 13 del; 99 mod

8310156: [Lilliput/JDK17] Specialize full-GC loops

Reviewed-by: shade

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PR: https://git.openjdk.org/lilliput-jdk17u/pull/32