Hi Babu,
On 5/10/2024 10:01 AM, Moger, Babu wrote:
> On 5/9/2024 10:18 PM, Reinette Chatre wrote:
>> On 5/9/2024 3:34 PM, Moger, Babu wrote:
>>> On 5/7/24 15:27, Reinette Chatre wrote:
>>>> 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"?
>
As I mentioned in [1] the "assign" concept is not clear (just to me perhaps?). It
really seems to be the marketing name percolating into the implementation. Why is
"assignable" needed to be in a "counter" variable name? Is a variable not by definition
"assignable"? Why not just, for example, "num_cntrs"? I believe that things to be
as simple and obvious as possible ... this just helps to reduce confusion.
My previous comment regarding counter scope is not addressed by a rename though and
I do not expect you to have the answer but I would like us to keep in mind how these
"counters" could end up getting used. We may just later, when soft-RMID/ABMC and MPAM
is understood, need to add a "counter scope" as well.
Reinette
[1] https://lore.kernel.org/lkml/0d94849c-828c-4f10-a6f8-e26cc4554909@xxxxxxxxx/
