Re: [RFC PATCH v3 03/17] x86/resctrl: Detect Assignable Bandwidth Monitoring feature details

Moger, Babu
2024-05-10T17:01:48Z

Hi Reinette,

On 5/9/2024 10:18 PM, Reinette Chatre wrote:
> Hi Babu,
>
> On 5/9/2024 3:34 PM, Moger, Babu wrote:
>> Hi Reinette,
>>
>> On 5/7/24 15:27, Reinette Chatre wrote:
>>> Hi Babu,
>>>
>>> On 5/6/2024 12:09 PM, Moger, Babu wrote:
>>>> On 5/3/24 18:26, Reinette Chatre wrote:
>>>>> On 3/28/2024 6:06 PM, Babu Moger wrote:
>>>
>>> ...
>>>
>>>>>> + * @mbm_assign_cntrs: Maximum number of assignable counters
>>>>>> */
>>>>>> struct rdt_resource {
>>>>>> int rid;
>>>>>> @@ -188,6 +198,8 @@ struct rdt_resource {
>>>>>> struct list_head evt_list;
>>>>>> unsigned long fflags;
>>>>>> bool cdp_capable;
>>>>>> + bool mbm_assign_capable;
>>>>>> + u32 mbm_assign_cntrs;
>>>>>> };
>>>>>
>>>>> Please check tabs vs spaces (in this whole series please).
>>>>
>>>> Sure. Will do.
>>>>
>>>>>
>>>>> I'm thinking that a new "MBM specific" struct within
>>>>> struct rdt_resource will be helpful to clearly separate the MBM related
>>>>> data. This will be similar to struct resctrl_cache for
>>>>> cache allocation and struct resctrl_membw for memory bandwidth
>>>>> allocation.
>>>>
>>>> Did you mean to move all the fields for monitoring to move to new struct?
>>>>
>>>> Struct resctrl_mbm {
>>>> int num_rmid;
>>>> bool mbm_assign_capable;
>>>> u32 mbm_assign_cntrs;
>>>> }:
>>>>
>>>
>>> Indeed, so not actually MBM specific but monitoring specific as you state (with
>>> appropriate naming?). This is purely to help organize data within struct rdt_resource
>>> and (similar to struct resctrl_cache and struct resctrl_membw) not a new
>>> structure expected to be passed around. I think evt_list can also be a member.
>>
>> How about this?
>>
>> Lets keep assign_capable in main structure(like we have mon_capable) and
>> move rest of them into new structure.
>>
>> Struct resctrl_mon {
>> int num_rmid;
>> struct list_head evt_list;
>> u32 num_assign_cntrs;
>> }:
>
> This looks like a good start. It certainly supports ABMC. I do not yet
> have a clear understanding about how this will support MPAM and soft-RMID/ABMC
> since the current implementation has an implicit scope of one counter per event per
> monitor group. It thus seem reasonable to have a new generic name of "cntrs".

How about renaming it to "assignable_counters"?

--
- Babu Moger