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

[Andrey Turbanov]

On Tue, 17 Jan 2023 17:24:20 GMT, Jatin Bhateja <jbhateja 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

test/micro/org/openjdk/bench/java/util/TestAdler32.java line 39:

> 37:     private byte[] bytes;
> 38: 
> 39:     @Param({"64", "128", "256", "512", "1024",  "2048", "5012", "8192", "16384", "32768", "65536"})

nit:
Suggestion:

    @Param({"64", "128", "256", "512", "1024", "2048", "5012", "8192", "16384", "32768", "65536"})

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

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