RFR: 8273297: AES/GCM non-AVX512+VAES CPUs suffer after 8267125 [v5]

[Andrew Haley]

On Wed, 22 Sep 2021 22:48:32 GMT, Smita Kamath <svkamath at openjdk.org> wrote:

>> Performance dropped up to 10% for 1k data after 8267125 for CPUs that do not support the new intrinsic. Tests run were crypto.full.AESGCMBench and crypto.full.AESGCMByteBuffer from the jmh micro benchmarks.
>> 
>> The problem is each instance of GHASH allocates 96 extra longs for the AVX512+VAES intrinsic regardless if the intrinsic is used. This extra table space should be allocated differently so that non-supporting CPUs do not suffer this penalty. This issue also affects non-Intel CPUs too.
>
> Smita Kamath has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Added htbl_entries constant to other architectures

Marked as reviewed by aph (Reviewer).

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PR: https://git.openjdk.java.net/jdk/pull/5402