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

[Jatin Bhateja]

On Tue, 6 Jul 2021 15:02:17 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

>> Hi @dean-long , @vnkozlov ,
>> Since the idea is to test KNL settings on any latest X86 Server platform we should also turn off following options.
>> 
>>  if (is_intel()) { // Intel cpus specific settings
>>     if (is_knights_family()) {
>>       _features &= ~CPU_VZEROUPPER;
>>       _features &= ~CPU_AVX512BW;
>>       _features &= ~CPU_AVX512VL;
>> +      _features &= ~CPU_AVX512DQ;
>> +      _features &= ~CPU_AVX512_VNNI;
>> +      _features &= ~CPU_AVX512_VAES;
>> +      _features &= ~CPU_AVX512_VPOPCNTDQ;
>> +      _features &= ~CPU_AVX512_VPCLMULQDQ;
>> +      _features &= ~CPU_AVX512_VBMI;
>> +      _features &= ~CPU_AVX512_VBMI2;
>>     }
>>   }
>
> Tests listed in [8269828](https://bugs.openjdk.java.net/browse/JDK-8269828) passed with additional KNL CPU features switched off as @jatin-bhateja suggested. But it does not solve our internal testing issue.
> 
> I will change bug's subject and flag name to be specific that it is VM emulation instead of KNL CPU.

Hi @vnkozlov , 
Thanks for clarifications, configuration of  VM guest mentions AVX512DQ feature which is not supported by KNL.
Below is the KNL features list generated using Intel's SDE (SW Dev Emulator).



SPROMPT>sde -knl -- cpuid -1 | grep "AVX512" | grep "true"
      AVX512F: AVX-512 foundation instructions = true
      AVX512PF: prefetch instructions          = true
      AVX512ER: exponent & reciprocal instrs   = true
      AVX512CD: conflict detection instrs      = true
SPROMPT>sde -knl -- cpuid -1 | grep "AVX512" | grep "false"
      AVX512DQ: double & quadword instructions = false
      AVX512IFMA: fused multiply add           = false
      AVX512BW: byte & word instructions       = false
      AVX512VL: vector length                  = false
      AVX512VBMI: vector byte manipulation     = false
      AVX512_VBMI2: byte VPCOMPRESS, VPEXPAND  = false
      AVX512_VNNI: neural network instructions = false
      AVX512_BITALG: bit count/shiffle         = false
      AVX512: VPOPCNTDQ instruction            = false
      AVX512_4VNNIW: neural network instrs     = false
      AVX512_4FMAPS: multiply acc single prec  = false
      AVX512_VP2INTERSECT: intersect mask regs = false


Regards

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