RFR: 8294073: Performance improvement for message digest implementations

[Xue-Lei Andrew Fan]

On Wed, 21 Sep 2022 18:29:08 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> @shipilev Good points and I agree with them.
>> 
>>> Are you getting +0.8% throughput on microbenchmarks?
>> 
>> Yes, I got it a few times. I tested on MacOS/M1 and Linux/AMD for 64/512/2048/16384 bytes.  As the improvement is not significant, the number was impacted by the platforms status/loading.  I can see improvement, but I did not get a stable +0.8%.
>> 
>> I got a more than +1% improvement in another algorithm implementation (SM3).  That's the reason I want to check out the JDK implementations.  But you let me convinced that this may not be worthy of the effort.  Thank you so much!
>> 
>>> https://bugs.openjdk.org/browse/JDK-8256523
>> 
>> Thank you so much for pointing this out.  From it, I learned something new that the Java inline may not work in some circumstance.  Impressed PR description!
>
>> But you let me convinced that this may not be worthy of the effort.
> 
> Let's think about it and not discount it right away. 1% improvement on OpenJDK scale is still quite significant, if we can show the non-interpreter modes benefit from it. Maybe older X86 and AArch64 are our targets, since it is not guaranteed to have SHA hardware intrinsics?

@shipilev Did you have further comment?  Thanks!

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PR: https://git.openjdk.org/jdk/pull/10365