On Tue, 12 May 2026 21:41:10 GMT, Volodymyr Paprotski <[email protected]> 
wrote:

>> This PR:
>> - changes existing AVX512 SHA3 intrinsic to be more parallel
>> - adds an AVX2 SHA3 intrinsic
>> - change `SHA3Parallel.java` to NR=4 (to be able to exploit the AVX512 
>> parallelism while keeping doubleKeccak for platforms where double 
>> parallelism is preferable. I experimented with NR=8 as well, does also gain 
>> a few percent, but I think NR=4 is sufficient tradeoff)
>> 
>> Performance gains:
>> - `MessageDigestBench.digest`:
>>   - AVX2: **16%-39%**
>>   - AVX512: **24%-33%**
>> - `SignatureBench.MLDSA.sign`
>>   - AVX2: **6-12%**
>>   - AVX512: **11%-18%**
>> - `SignatureBench.MLDSA.verify`
>>   - AVX2: **2%-14%**
>>   - AVX512: **31%-40%**
>> - `KEMBench.MLKEM`
>>   - AVX2: **~5%**
>>   - AVX512: **14%-23%**
>> - `KEMBench.JSSE_*`
>>   - appears unaffected
>> 
>> Note on intrinsics. (As noted in the code..) there are multiple entrypoints 
>> wrapping the same intrinsic..
>> - `SHA3.implCompress`: single blockSize of user data xored with keccak
>> - `DigestBase.implCompressMultiBlock`: loop over user data and xor with 
>> keccak
>> - `SHA3Parallel.doubleKeccak`: (still used for AVX2) no message data, just 
>> two state vectors
>> - `SHA3Parallel.quadKeccak`: (AVX512 benefit) no message data, four state 
>> vectors
>> 
>> Note 1: `make test 
>> TEST="micro:org.openjdk.bench.javax.crypto.full.MessageDigestBench 
>> micro:org.openjdk.bench.javax.crypto.full.SignatureBench.MLDSA 
>> micro:org.openjdk.bench.javax.crypto.full.KEMBench"`
>> Note 2: I have left more targeted fuzzing and benchmarks out of this PR, but 
>> they are preserved at [on my 
>> branch](https://github.com/vpaprotsk/jdk/compare/sha3-avx-quad...vpaprotsk:jdk:sha3-avx-quad-extras?expand=1).
>>  If there is something you rather see pulled in.. (otherwise, can include a 
>> diff in JBS for 'future reference')
>> 
>> ---------
>> - [X] I confirm that I make this contribution in accordance with the 
>> [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai).
>
> Volodymyr Paprotski has updated the pull request incrementally with one 
> additional commit since the last revision:
> 
>   comments from Andrew Dinn

src/hotspot/cpu/x86/assembler_x86.cpp line 3877:

> 3875:   }
> 3876:   vex_prefix(dst, 0, src->encoding(), VEX_SIMD_66, VEX_OPCODE_0F, 
> &attributes);
> 3877:   emit_int8(0x6F);

Should this not be 0x7F?

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/31125#discussion_r3238108363

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