[11] RFR (XS): JDK-8198293: AARCH64 - Add CPU detection code for Cavium Thunder X2

[Dmitry Samersoff]

Dmitry,

I would prefer to have this code better readable/maintainable ever at
the cost of some extra lines.

i.e.

if (_cpu == CPU_CAVIUM) {
  if (_model == CAVIUM_THUNDER_X) //0xA1 {
      ...
  }
  if (_model == CAVIUM_THUNDER_X2) //0xAF {
    ...
  }
}
else if (_cpu == CPU_BROADCOM ) {
   if (_model == 0x516) {
       ...
   }
}

-Dmitry


On 19.02.2018 17:22, Dmitry Chuyko wrote:
> I also made webrev for convenience.
> 
> webrev: http://cr.openjdk.java.net/~dchuyko/8198293/webrev.00/
> rfe: https://bugs.openjdk.java.net/browse/JDK-8198293
> 
> -Dmitry
> 
> On 02/16/2018 07:37 PM, Dmitry Chuyko wrote:
>>
>> rfe link corrected: https://bugs.openjdk.java.net/browse/JDK-8198293
>>
>> On 02/16/2018 07:35 PM, Dmitry Chuyko wrote:
>>>
>>> Hello,
>>>
>>> Please review a small change in vendor specific features for Cavium CPUs.
>>>
>>> T88 should be determined more accurate with its model number.
>>> T99 may have 2 vendor-model combinations.
>>>
>>> Flag values for T99 are raw first approximation, I've created a
>>> separate sub-task to check them more precisely.
>>>
>>> rfe: https://bugs.openjdk.java.net/browse/JDK-8198293
>>> patch: below
>>>
>>> -Dmitry
>>>
>>> diff -r 82d9d5744e5f src/hotspot/cpu/aarch64/vm_version_aarch64.cpp
>>> --- a/src/hotspot/cpu/aarch64/vm_version_aarch64.cpp    Fri Feb 16
>>> 12:18:09 2018 +0100
>>> +++ b/src/hotspot/cpu/aarch64/vm_version_aarch64.cpp    Fri Feb 16
>>> 19:15:44 2018 +0300
>>> @@ -193,7 +193,9 @@
>>>    }
>>>  
>>>    // Enable vendor specific features
>>> -  if (_cpu == CPU_CAVIUM) {
>>> +
>>> +  // ThunderX
>>> +  if (_cpu == CPU_CAVIUM && (_model == 0xA1)) {
>>>      if (_variant == 0) _features |= CPU_DMB_ATOMICS;
>>>      if (FLAG_IS_DEFAULT(AvoidUnalignedAccesses)) {
>>>        FLAG_SET_DEFAULT(AvoidUnalignedAccesses, true);
>>> @@ -202,6 +204,20 @@
>>>        FLAG_SET_DEFAULT(UseSIMDForMemoryOps, (_variant > 0));
>>>      }
>>>    }
>>> +  // ThunderX2
>>> +  if ((_cpu == CPU_CAVIUM && (_model == 0xAF)) ||
>>> +      (_cpu == CPU_BROADCOM && (_model == 0x516))) {
>>> +    if (FLAG_IS_DEFAULT(AvoidUnalignedAccesses)) {
>>> +      FLAG_SET_DEFAULT(AvoidUnalignedAccesses, true);
>>> +    }
>>> +    if (FLAG_IS_DEFAULT(UseSIMDForMemoryOps)) {
>>> +      FLAG_SET_DEFAULT(UseSIMDForMemoryOps, true);
>>> +    }
>>> +    if (FLAG_IS_DEFAULT(UseFPUForSpilling)) {
>>> +      FLAG_SET_DEFAULT(UseFPUForSpilling, true);
>>> +    }
>>> +  }
>>> +
>>>    if (_cpu == CPU_ARM && (_model == 0xd03 || _model2 == 0xd03))
>>> _features |= CPU_A53MAC;
>>>    if (_cpu == CPU_ARM && (_model == 0xd07 || _model2 == 0xd07))
>>> _features |= CPU_STXR_PREFETCH;
>>>    // If an olde style /proc/cpuinfo (cpu_lines == 1) then if _model
>>> is an A57 (0xd07)
>>>
>>
> 


-- 
Dmitry Samersoff
http://devnull.samersoff.net
* There will come soft rains ...

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