On Mon, 26 Jan 2026 04:25:44 GMT, Ben Perez <[email protected]> wrote:
>> An aarch64 implementation of the `MontgomeryIntegerPolynomial256.mult()`
>> method and `IntegerPolynomial.conditionalAssign()`. Since 64-bit
>> multiplication is not supported on Neon and manually performing this
>> operation with 32-bit limbs is slower than with GPRs, a hybrid neon/gpr
>> approach is used. Neon instructions are used to compute intermediate values
>> used in the last two iterations of the main "loop", while the GPRs compute
>> the first few iterations. At the method level this improves performance by
>> ~9% and at the API level roughly 5%.
>>
>> Performance no intrinsic:
>>
>> Benchmark (isMontBench) Mode Cnt Score
>> Error Units
>> PolynomialP256Bench.benchMultiply true thrpt 8 2427.562 ±
>> 24.923 ops/s
>> PolynomialP256Bench.benchMultiply false thrpt 8 1757.495 ±
>> 41.805 ops/s
>> PolynomialP256Bench.benchSquare true thrpt 8 2435.202 ±
>> 20.822 ops/s
>> PolynomialP256Bench.benchSquare false thrpt 8 2420.390 ±
>> 33.594 ops/s
>>
>> Benchmark (algorithm) (dataSize) (keyLength)
>> (provider) Mode Cnt Score Error Units
>> SignatureBench.ECDSA.sign SHA256withECDSA 1024 256
>> thrpt 40 8439.881 ± 29.838 ops/s
>> SignatureBench.ECDSA.sign SHA256withECDSA 16384 256
>> thrpt 40 7990.614 ± 30.998 ops/s
>> SignatureBench.ECDSA.verify SHA256withECDSA 1024 256
>> thrpt 40 2677.737 ± 8.400 ops/s
>> SignatureBench.ECDSA.verify SHA256withECDSA 16384 256
>> thrpt 40 2619.297 ± 9.737 ops/s
>>
>> Benchmark (algorithm) (keyLength)
>> (kpgAlgorithm) (provider) Mode Cnt Score Error Units
>> KeyAgreementBench.EC.generateSecret ECDH 256
>> EC thrpt 40 1905.369 ± 3.745 ops/s
>>
>> Benchmark (algorithm) (keyLength)
>> (kpgAlgorithm) (provider) Mode Cnt Score Error Units
>> KeyAgreementBench.EC.generateSecret ECDH 256
>> EC thrpt 40 1903.997 ± 4.092 ops/s
>>
>>
>> Performance with intrinsic
>>
>> Benchmark (isMontBench) Mode Cnt Score
>> Error Units
>> PolynomialP256Bench.benchMultiply true thrpt 8 2676.599 ±
>> 24.722 ops/s
>> PolynomialP256Bench.benchMultiply false thrpt 8 1770.589 ±
>> 2.584 op...
>
> Ben Perez has updated the pull request incrementally with one additional
> commit since the last revision:
>
> Added conditionalAssign() intrinsic, changed mult intrinsic to use hybrid
> neon/gpr approach
src/hotspot/cpu/aarch64/stubGenerator_aarch64.cpp line 7933:
> 7931: __ ldr(b9, Address(bLimbs, 64));
> 7932: __ ldr(b10, Address(bLimbs, 72));
> 7933:
You could use the existing macro generator method `vs_ldpq` to plant these load
instructions
vs_ldpq(a_vec, aLimbs);
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/27946#discussion_r2727688196
