RFR: 8300917: Regression 2x and bimodal startup on Mac aarch64 in b27

[Per Minborg]

On Wed, 25 Jan 2023 12:26:26 GMT, Per Minborg <pminborg at openjdk.org> wrote:

> This PR proposed to reduce contention in synchronized methods mainly by doing I/O operations outside synch blocks.

The potential performance improvement in determining if native access is enabled is a small part of the overall benchmarks in the `LoopOverOfAddress` benchmarks:


Baseline
Benchmark                                         Mode  Cnt  Score   Error  Units
LoopOverOfAddress.segment_loop_addr_size          avgt   30  0.563 ± 0.005  ms/op


PR
Benchmark                                         Mode  Cnt  Score   Error  Units
LoopOverOfAddress.segment_loop_addr_size          avgt   30  0.558 ± 0.002  ms/op

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PR: https://git.openjdk.org/jdk/pull/12193