RFR: 8255351: Add detection for Graviton 1 & 2 CPUs

Mon Nov 23 22:08:59 UTC 2020

On Mon, 23 Nov 2020 21:19:34 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

>> This commit adds detection for Graviton 1 (as Cortex-A72) and for Graviton 2 (as Neoverse N1) and enables UseSIMDForMemoryOps for them.
>> 
>> The patch passed jtreg tier1-2 and all gtest tests with linux-aarch64-server-release build.
>
> src/hotspot/cpu/aarch64/vm_version_aarch64.cpp line 169:
> 
>> 167:   if (_cpu == CPU_ARM && (_model == 0xd08 || _model2 == 0xd08)) {
>> 168:     if (FLAG_IS_DEFAULT(UseSIMDForMemoryOps)) {
>> 169:       FLAG_SET_DEFAULT(UseSIMDForMemoryOps, true);
> 
> What about A73? Should this flag be true for it too?

Hi Vladimir,
Thank you for reviewing the changes.
Yes, it can be enabled. However I found only HiKey960/970 by Linaro use A73. Other devices are phones.
I can do this if Linaro engineers agree.

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PR: https://git.openjdk.java.net/jdk/pull/1315