RFR: 8329031: CPUID feature detection for Advanced Performance Extensions (Intel® APX) [v3]

[Jatin Bhateja]

On Fri, 7 Jun 2024 15:10:57 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

>> Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Review comments addressed.
>
> src/hotspot/cpu/x86/vm_version_x86.cpp line 882:
> 
>> 880: 
>> 881: void VM_Version::report_apx_state_restore_warning() {
>> 882:   tty->print("warning: Unsuccessful EGPRs state restoration across signal handling, setting UseAPX to false.\n");
> 
> This print is fine during development but I would instead save some value in memory to indicate that OS does not save/restore APX. And then check it after we execute this assembler code. Similar how we do that for AVX.
> You would not need to do runtime call and this method then.
> Note: `tty->print()` can do "nasty"/unexpected things which you want to avoid.

Hi @vnkozlov , doing a lazy restored state comparison now to align with existing AVX handling.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18562#discussion_r1631865373