RFR: 8371571: Consolidate and enhance bulk memory segment ops benchmarks

[Maurizio Cimadamore]

On Wed, 12 Nov 2025 09:14:15 GMT, Per Minborg <pminborg at openjdk.org> wrote:

> Here are some examples of benchmark output (only one or two sizes are shown for brevity):
> 
> ```
> Benchmark                                 (alignment)  (segmentType)  (size)  Mode  Cnt  Score   Error  Units
> SegmentBulkHash.Array.array                       N/A            N/A       2  avgt   30  2.681 ± 0.137  ns/op
> SegmentBulkHash.Segment.hash                  ALIGNED           HEAP       2  avgt   30  3.531 ± 0.343  ns/op
> SegmentBulkHash.Segment.hash                  ALIGNED         NATIVE       2  avgt   30  5.070 ± 0.963  ns/op
> SegmentBulkHash.Segment.hash                UNALIGNED           HEAP       2  avgt   30  3.498 ± 0.238  ns/op
> SegmentBulkHash.Segment.hash                UNALIGNED         NATIVE       2  avgt   30  4.158 ± 0.154  ns/op
> SegmentBulkHash.Segment.hashLoopIntInt        ALIGNED           HEAP       2  avgt   30  4.470 ± 0.215  ns/op
> SegmentBulkHash.Segment.hashLoopIntInt        ALIGNED         NATIVE       2  avgt   30  3.906 ± 0.233  ns/op
> SegmentBulkHash.Segment.hashLoopIntInt      UNALIGNED           HEAP       2  avgt   30  4.531 ± 0.246  ns/op
> SegmentBulkHash.Segment.hashLoopIntInt      UNALIGNED         NATIVE       2  avgt   30  3.619 ± 0.095  ns/op
> SegmentBulkHash.Segment.hashLoopIntLong       ALIGNED           HEAP       2  avgt   30  4.226 ± 0.266  ns/op
> SegmentBulkHash.Segment.hashLoopIntLong       ALIGNED         NATIVE       2  avgt   30  3.223 ± 0.351  ns/op
> SegmentBulkHash.Segment.hashLoopIntLong     UNALIGNED           HEAP       2  avgt   30  4.125 ± 0.293  ns/op
> SegmentBulkHash.Segment.hashLoopIntLong     UNALIGNED         NATIVE       2  avgt   30  3.329 ± 0.221  ns/op
> SegmentBulkHash.Segment.hashLoopLongLong      ALIGNED           HEAP       2  avgt   30  3.603 ± 0.285  ns/op
> SegmentBulkHash.Segment.hashLoopLongLong      ALIGNED         NATIVE       2  avgt   30  3.048 ± 0.172  ns/op
> SegmentBulkHash.Segment.hashLoopLongLong    UNALIGNED           HEAP       2  avgt   30  3.666 ± 0.180  ns/op
> SegmentBulkHash.Segment.hashLoopLongLong    UNALIGNED         NATIVE       2  avgt   30  3.237 ± 0.257  ns/op
> ```
> 

Interesting -- the base version is faster for heap than native.
But the loop versions are the opposite. I wonder why?

(the other benchmarks don't seem to have this trait)

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

PR Comment: https://git.openjdk.org/jdk/pull/28260#issuecomment-3521960689