Re: [PATCH v18 3/8] numa: Extend CLI to provide memory side cache information

[Tao Xu <tao3.xu@intel.com>]

On 11/28/2019 10:46 AM, Tao Xu wrote:
> On 11/27/2019 5:56 PM, Markus Armbruster wrote:
>> Tao Xu <tao3.xu@intel.com> writes:
>>
>>> From: Liu Jingqi <jingqi.liu@intel.com>
>>>
>>> Add -numa hmat-cache option to provide Memory Side Cache Information.
>>> These memory attributes help to build Memory Side Cache Information
>>> Structure(s) in ACPI Heterogeneous Memory Attribute Table (HMAT).
>>
>> Please mention this requires -machine hmat=on.
> 
> OK I will add these for 3 related patches.
>>
>>> Reviewed-by: Igor Mammedov <imammedo@redhat.com>
>>> Reviewed-by: Daniel Black <daniel@linux.ibm.com>
>>> Signed-off-by: Liu Jingqi <jingqi.liu@intel.com>
>>> Signed-off-by: Tao Xu <tao3.xu@intel.com>
>> [...]
>>> diff --git a/qapi/machine.json b/qapi/machine.json
>>> index c741649d7b..3d0ba226a9 100644
>>> --- a/qapi/machine.json
>>> +++ b/qapi/machine.json
>>> @@ -428,10 +428,12 @@
>>>   #
>>>   # @hmat-lb: memory latency and bandwidth information (Since: 5.0)
>>>   #
>>> +# @hmat-cache: memory side cache information (Since: 5.0)
>>> +#
>>>   # Since: 2.1
>>>   ##
>>>   { 'enum': 'NumaOptionsType',
>>> -  'data': [ 'node', 'dist', 'cpu', 'hmat-lb' ] }
>>> +  'data': [ 'node', 'dist', 'cpu', 'hmat-lb', 'hmat-cache' ] }
>>>   ##
>>>   # @NumaOptions:
>>> @@ -447,7 +449,8 @@
>>>       'node': 'NumaNodeOptions',
>>>       'dist': 'NumaDistOptions',
>>>       'cpu': 'NumaCpuOptions',
>>> -    'hmat-lb': 'NumaHmatLBOptions' }}
>>> +    'hmat-lb': 'NumaHmatLBOptions',
>>> +    'hmat-cache': 'NumaHmatCacheOptions' }}
>>>   ##
>>>   # @NumaNodeOptions:
>>> @@ -647,6 +650,77 @@
>>>       '*latency': 'uint64',
>>>       '*bandwidth': 'size' }}
>>> +##
>>> +# @HmatCacheAssociativity:
>>> +#
>>> +# Cache associativity in the Memory Side Cache
>>> +# Information Structure of HMAT
>>> +#
>>> +# For more information of @HmatCacheAssociativity see
>>> +# the chapter 5.2.27.5: Table 5-147 of ACPI 6.3 spec.
>>
>>    # Cache associativity in the Memory Side Cache Information Structure
>>    # of HMAT
>>    #
>>    # For more information of @HmatCacheAssociativity, see chapter
>>    # 5.2.27.5: Table 5-147 of ACPI 6.3 spec.
>>
>>> +#
>>> +# @none: None
>>
>> What does cache associativity @none mean?  A none-associative cache?  I
>> guess it makes sense to people familiar with the ACPI spec...
>>
> 
> This means this proximity domain has no memory cache, thus none for 
> Cache associativity, I will add more description about this.

Read again about ACPI spec, there is no description about 'none'. In
linux kernel HMAT code, this is handle as "other", maybe means not 
provided. I will also add a check when level is none, the associativity, 
policy and line_size should be none or 0.