RFR: 8360776: Disable Intel APX by default and enable it with -XX:+UnlockExperimentalVMOptions -XX:+UseAPX in all builds [v2]

[Tobias Hartmann]

On Mon, 30 Jun 2025 18:30:24 GMT, Srinivas Vamsi Parasa <sparasa at openjdk.org> wrote:

>> Currently, APX is not enabled consistently between product and debug builds.
>> 
>> If the hardware supports Intel APX:
>> 
>> 1) In product builds, APX is disabled by default, even if the user explicitly enables it using `-XX:+UnlockExperimentalVMOptions -XX:+UseAPX`.
>> 
>> 2) In debug builds, APX is enabled by default regardless of whether the user explicitly enables it or not.
>> 
>> **The goal of this PR is to enable APX for both product and debug builds if and only if the user explicitly enables it using `-XX:+UnlockExperimentalVMOptions -XX:+UseAPX`.**
>
> Srinivas Vamsi Parasa has refreshed the contents of this pull request, and previous commits have been removed. The incremental views will show differences compared to the previous content of the PR. The pull request contains one new commit since the last revision:
> 
>   8360776: Enable -XX:+UseAPX as experimental feature in all builds

Testing is clean.

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PR Comment: https://git.openjdk.org/jdk/pull/26029#issuecomment-3027027518