[jdk17] RFR: 8269825: [TESTBUG] Missing testing for x86 KNL platforms [v2]

[Vladimir Kozlov]

On Tue, 6 Jul 2021 21:46:22 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

>> Knights family of X86 Intel CPU (KNL) does not support some of avx512 features (AVX512VL/BW) and have other restrictions. We may not have such kind of machines in our testing environment and may miss bugs as JBS history shows (look recent fixes for KNL).
>> On other hand we have some Windows VM instances which seem emulate KNL configuration and limit avx512 instructions on CPU which supports full set. Recent bug JDK-8269775 shows such example.
>> I suggest to add -XX:+UseKNLSetting x86 diagnostic flag to emulate KNL settings in HotSpot VM to test such configuration.
>
> Vladimir Kozlov has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:
> 
>  - Exclude more CPU features to emulate KNL cpu
>  - Merge branch 'master' into JDK-8269825
>  - 8269825: [TESTBUG] Missing testing for x86 KNL platforms

The update changes were suggested by Jatin.

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PR: https://git.openjdk.java.net/jdk17/pull/205