RFR: 8287788: reuse intermediate segments allocated during FFM stub invocations [v2]

[Matthias Ernst]

On Mon, 20 Jan 2025 14:06:33 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

>> Matthias Ernst has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Implementation notes.
>
> test/micro/org/openjdk/bench/java/lang/foreign/points/PointsAlloc.java line 81:
> 
>> 79:             return Circle.byPtr(arena, NUM_CIRCLE_POINTS);
>> 80:         }
>> 81:     }
> 
> I think it would be better to put the new benchmark in a separate benchmark class (e.g. a new variant of the `CallOverheadXXX` benchmark. There should already be some examples of benchmarks that pass structs), where the time unit is set to nanoseconds, so we can measure just the overhead of a single call.

Done.

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PR Review Comment: https://git.openjdk.org/jdk/pull/23142#discussion_r1922633902