RFR: 8309130: x86_64 AVX512 intrinsics for Arrays.sort methods (int, long, float and double arrays) [v42]

[Srinivas Vamsi Parasa]

> The goal is to develop faster sort routines for x86_64 CPUs by taking advantage of AVX512 instructions. This enhancement provides an order of magnitude speedup for Arrays.sort() using int, long, float and double arrays.
> 
> This PR shows upto ~7x improvement for 32-bit datatypes (int, float) and upto ~4.5x improvement for 64-bit datatypes (long, double) as shown in the performance data below.
> 
> 
> **Arrays.sort performance data using JMH benchmarks for arrays with random data** 
> 
> |	Arrays.sort benchmark	|	Array Size	|	Baseline (us/op)	|	AVX512 Sort (us/op)	|	Speedup	|
> |	---	|	---	|	---	|	---	|	---	|
> |	ArraysSort.doubleSort	|	10	|	0.034	|	0.035	|	1.0	|
> |	ArraysSort.doubleSort	|	25	|	0.116	|	0.089	|	1.3	|
> |	ArraysSort.doubleSort	|	50	|	0.282	|	0.291	|	1.0	|
> |	ArraysSort.doubleSort	|	75	|	0.474	|	0.358	|	1.3	|
> |	ArraysSort.doubleSort	|	100	|	0.654	|	0.623	|	1.0	|
> |	ArraysSort.doubleSort	|	1000	|	9.274	|	6.331	|	1.5	|
> |	ArraysSort.doubleSort	|	10000	|	323.339	|	71.228	|	**4.5**	|
> |	ArraysSort.doubleSort	|	100000	|	4471.871	|	1002.748	|	**4.5**	|
> |	ArraysSort.doubleSort	|	1000000	|	51660.742	|	12921.295	|	**4.0**	|
> |	ArraysSort.floatSort	|	10	|	0.045	|	0.046	|	1.0	|
> |	ArraysSort.floatSort	|	25	|	0.103	|	0.084	|	1.2	|
> |	ArraysSort.floatSort	|	50	|	0.285	|	0.33	|	0.9	|
> |	ArraysSort.floatSort	|	75	|	0.492	|	0.346	|	1.4	|
> |	ArraysSort.floatSort	|	100	|	0.597	|	0.326	|	1.8	|
> |	ArraysSort.floatSort	|	1000	|	9.811	|	5.294	|	1.9	|
> |	ArraysSort.floatSort	|	10000	|	323.955	|	50.547	|	**6.4**	|
> |	ArraysSort.floatSort	|	100000	|	4326.38	|	731.152	|	**5.9**	|
> |	ArraysSort.floatSort	|	1000000	|	52413.88	|	8409.193	|	**6.2**	|
> |	ArraysSort.intSort	|	10	|	0.033	|	0.033	|	1.0	|
> |	ArraysSort.intSort	|	25	|	0.086	|	0.051	|	1.7	|
> |	ArraysSort.intSort	|	50	|	0.236	|	0.151	|	1.6	|
> |	ArraysSort.intSort	|	75	|	0.416	|	0.332	|	1.3	|
> |	ArraysSort.intSort	|	100	|	0.63	|	0.521	|	1.2	|
> |	ArraysSort.intSort	|	1000	|	10.518	|	4.698	|	2.2	|
> |	ArraysSort.intSort	|	10000	|	309.659	|	42.518	|	**7.3**	|
> |	ArraysSort.intSort	|	100000	|	4130.917	|	573.956	|	**7.2**	|
> |	ArraysSort.intSort	|	1000000	|	49876.307	|	6712.812	|	**7.4**	|
> |	ArraysSort.longSort	|	10	|	0.036	|	0.037	|	1.0	|
> |	ArraysSort.longSort	|	25	|	0.094	|	0.08	|	1.2	|
> |	ArraysSort.longSort	|	50	|	0.218	|	0.227	|	1.0	|
> |	ArraysSort.longSort	|	75	|	0.466	|	0.402	|	1.2	|
> |	ArraysSort.longSort	|	100	|	0.76	|	0.58	|	1.3	|
> |	ArraysSort.longSort	|	1000	|	10.449	|	6.239	|	1.7	|
> |	ArraysSort.longSort	|	10000	|	307.074	|	70.284	|	**4.4**	|
> |	ArraysSor...

Srinivas Vamsi Parasa has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 45 commits:

 - fix code style and formatting
 - Merge branch 'master' of https://git.openjdk.java.net/jdk into avx512sort
 - Update CompileThresholdScaling only for the sort and partition intrinsics; update build script to remove nested if
 - change variable names of indexPivot* to pivotIndex*
 - Update DualPivotQuicksort.java
 - Rename arraySort and arrayPartition Java methods to sort and partition. Cleanup some comments
 - Remove the unnecessary exception in single pivot partitioning fallback method
 - Move functional interfaces close to the associated methods
 - Refactor the sort and partition intrinsics to accept method references for fallback functions
 - Refactor stub handling to use a generic function for all types
 - ... and 35 more: https://git.openjdk.org/jdk/compare/a1c9587c...a5262d86

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

Changes: https://git.openjdk.org/jdk/pull/14227/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14227&range=41
  Stats: 3410 lines in 22 files changed: 2902 ins; 292 del; 216 mod
  Patch: https://git.openjdk.org/jdk/pull/14227.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14227/head:pull/14227

PR: https://git.openjdk.org/jdk/pull/14227