[jdk17u-dev] RFR: 8284578: Relax InterpreterCodelet stub alignment [v6]

[Dmitry Chuyko]

On Fri, 30 Dec 2022 10:35:28 GMT, Dmitry Chuyko <dchuyko at openjdk.org> wrote:

>> This change improves density of interpreter codelets. I have no intent to backport JDK-8281467 [1] (Allow larger OptoLoopAlignment and CodeEntryAlignment), entire JDK-8283298 [2] (productize CodeCacheSegmentSize) and its related change in stubRoutines.cpp JDK-8282355 [3].
>> 
>> However I suppose that Modification of MethodHandles::generate_adapters() from JDK-8283298 which makes blob size more accurate is related to this fix, so I included it here. JDK-8283298 modifications of TemplateInterpreter::initialize_stub() are overwritten by the changes from the original JDK-8284578 patch.
>> 
>> So this patch consists of
>> - Original JDK-8284578 altered to be applicable without JDK-8283298 and JDK-8264207 [4] (can be backported afterwards).
>> - MethodHandles::generate_adapters() and copyrights from JDK-8283298.
>> 
>> Testing: tier1, tier2 on x86 and aarch64 (release)
>> 
>> [0] https://bugs.openjdk.org/browse/JDK-8284578
>> [1] https://bugs.openjdk.org/browse/JDK-8281467
>> [2] https://bugs.openjdk.org/browse/JDK-8283298
>> [3] https://bugs.openjdk.org/browse/JDK-8282355
>> [4] https://bugs.openjdk.org/browse/JDK-8264207
>
> Dmitry Chuyko has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision:
> 
>  - Merge branch 'openjdk:master' into JDK-8284578
>  - Merge branch 'openjdk:master' into JDK-8284578
>  - Merge branch 'openjdk:master' into JDK-8284578
>  - Backport 2241a057050ed521cfbfbe8a758353e621dee15f

PPC was mentioned originally as the most impacted platform, however experiments on x86 and aarch64 stopped no performance improvement (interpreter, startup). So the change should be considered as an optional clean-up, closing for now.

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PR: https://git.openjdk.org/jdk17u-dev/pull/753