Integrated: 8298472: AArch64: Detect Ampere-1 and Ampere-1A CPUs and set default options

[Patrick Zhang]

On Fri, 6 Jan 2023 08:27:28 GMT, Patrick Zhang <qpzhang at openjdk.org> wrote:

> This patch is to add CPU detection for Ampere-1 and Ampere-1A and set -XX:+UseSIMDForMemoryOps by default. In addition, an `enum Ampere_CPU_Model ` got introduced in order to clearly describe all Ampere CPUs in `src/hotspot/cpu/aarch64/vm_version_aarch64.hpp`.
> 
> Tests done:
> 1. Jtreg tier1 sanity check on Ampere Altra AArch64 platforms, and Ampere-1 systems as well. No new issue found.
> 4. GitHub Actions (GHA) sanity tests: https://github.com/cnqpzhang/jdk/actions/runs/3845722221
> 3. OpenJDK bundled JMH, `make run-test TEST="micro:java.lang.ArrayCopy*" `, SIMD vs NoSIMD ratios are mostly positive. For example, `java.lang.ArrayCopyAligned.testChar` with `-p length=600` showed +42% improvement on Ampere-1. 
> 2. Ran [JMH JDK Microbenchmarks](https://github.com/openjdk/jmh-jdk-microbenchmarks), ~1500 cases. No obvious perf regression found.
> 
> Signed-off-by: Patrick Zhang <patrick at os.amperecomputing.com>

This pull request has now been integrated.

Changeset: 70684574
Author:    Patrick Zhang <qpzhang at openjdk.org>
Committer: Nick Gasson <ngasson at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/706845743699efb01994e2d12c65023a3e972b77
Stats:     18 lines in 2 files changed: 15 ins; 0 del; 3 mod

8298472: AArch64: Detect Ampere-1 and Ampere-1A CPUs and set default options

Reviewed-by: aph, ngasson

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PR: https://git.openjdk.org/jdk/pull/11878