RFR: 8287788: reuse intermediate segments allocated during FFM stub invocations [v6]

[Jorn Vernee]

On Mon, 20 Jan 2025 18:32:55 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

>> Matthias Ernst has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   whitespace :scream:
>
> test/micro/org/openjdk/bench/java/lang/foreign/CallOverheadByValue.java line 54:
> 
>> 52: @State(org.openjdk.jmh.annotations.Scope.Thread)
>> 53: @OutputTimeUnit(TimeUnit.NANOSECONDS)
>> 54: @Fork(value = 1, jvmArgs = {"--enable-native-access=ALL-UNNAMED", "-Djava.library.path=micro/native"})
> 
> Please set the fork value to at least 3, so we can spot bimodal results.

Actually, on my machine I'm already seeing some bimodal results, where sometimes the `byValue` case takes twice as long.

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PR Review Comment: https://git.openjdk.org/jdk/pull/23142#discussion_r1922754343