RFR: 8300208: Optimize Adler32 stub for AVX-512 targets.

[Jatin Bhateja]

On Fri, 27 Jan 2023 01:38:22 GMT, Sandhya Viswanathan <sviswanathan at openjdk.org> wrote:

>> Patch optimizes Adler32 stub for AVX512 target.
>> 
>> Main computation loop now uses zero extended lane widening load vector operation.
>> 
>> New sequence also honors AVX3Thresholds so that implementation uses existing AVX2 instruction sequence on relevant targets
>> if input size is smaller than threshold limit (default 4096).
>> 
>> Following are the result of an [existing JMH micro ](https://github.com/openjdk/jdk/blob/master/test/micro/org/openjdk/bench/java/util/TestAdler32.java)on various targets.
>> 
>> **System Configurations : Turbo frequency scaling is disabled, all the data is collected at fixed frequency of 2.8 GHz.
>> SUT1   : Intel® Xeon® Platinum 8480+ Processor (Sapphire Rapids)  56C 2S
>> SUT2   : Intel(R) Xeon(R) Platinum 8380 CPU (Icelake Server) 40C 2S
>> SUT3   : Intel(R) Xeon(R) Platinum 8280 CPU (Cascadelake Server) 28C 2S**
>> 
>> 
>> ![image](https://user-images.githubusercontent.com/59989778/212934730-68717a61-191f-4dba-8c83-2eddf6007a47.png)
>> 
>> ![image](https://user-images.githubusercontent.com/59989778/212934945-cada95ad-c93c-487f-bacc-928a2e3b5c21.png)
>> 
>> ![image](https://user-images.githubusercontent.com/59989778/212935059-511aca3b-c736-40a2-bff6-89caf0664828.png)
>> 
>> 
>> Please review and share your feedback.
>> 
>> Best Regards,
>> Jatin
>
> Could you please also update the test/hotspot/jtreg/compiler/intrinsics/zip/TestAdler32.java to throw Exception on failure?

Hi @sviswa7 , your comments have been addressed.

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PR: https://git.openjdk.org/jdk/pull/12045