Integrated: 8269404: Base64 Encoding optimization enhancements for x86 using AVX-512

[Scott Gibbons]

On Sat, 26 Jun 2021 14:39:53 GMT, Scott Gibbons <github.com+6704669+asgibbons at openjdk.org> wrote:

> Enhance the Base64 Encode intrinsic for x86 using AVX-512 to get better performance. Also allow for performance improvement on non-AVX-512 enabled platforms.
> 
> Added AVX-512 code for encoding Base64 blocks, including slight improvements for non-AVX-512 x86 platforms.
> 
> Running the Base64Decode benchmark, this change increases decode performance by an average of 2.6x with a maximum 9.7x for buffers > ~20k.  The numbers are given in the table below.
> 
> **Base Score** is without intrinsic support, **Optimized Score** is using this intrinsic, and **Gain** is **Base** / **Optimized**.
> 
> Benchmark Name | Base Score | Optimized Score | Gain
> -- | -- | -- | --
> testBase64Encode size 1 | 8.10 | 8.04 | 1.01
> testBase64Encode size 2 | 8.51 | 8.43 | 1.01
> testBase64Encode size 3 | 11.08 | 10.72 | 1.03
> testBase64Encode size 6 | 13.98 | 13.12 | 1.07
> testBase64Encode size 7 | 14.44 | 13.38 | 1.08
> testBase64Encode size 9 | 15.44 | 14.37 | 1.07
> testBase64Encode size 10 | 16.13 | 14.97 | 1.08
> testBase64Encode size 48 | 27.14 | 23.23 | 1.17
> testBase64Encode size 512 | 123.86 | 30.75 | 4.03
> testBase64Encode size 1000 | 224.42 | 37.71 | 5.95
> testBase64Encode size 20000 | 4202.11 | 430.16 | 9.77

This pull request has now been integrated.

Changeset: 9cac94d5
Author:    Scott Gibbons <scott.gibbons at intel.com>
Committer: Sandhya Viswanathan <sviswanathan at openjdk.org>
URL:       https://git.openjdk.java.net/jdk/commit/9cac94d581f240c10fe8fff2f803109a1ae30637
Stats:     710 lines in 5 files changed: 349 ins; 235 del; 126 mod

8269404: Base64 Encoding optimization enhancements for x86 using AVX-512

Reviewed-by: kvn, sviswanathan

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PR: https://git.openjdk.java.net/jdk/pull/4601