[PATCH v2 8/8] drm/xe/pmu: Add PMU support for engine busyness

[Umesh Nerlige Ramappa]

On Thu, Dec 19, 2024 at 11:17:16AM +0530, Riana Tauro wrote:
>
>
>On 12/18/2024 8:21 PM, Riana Tauro wrote:
>>
>>
>>On 12/18/2024 7:43 PM, Lucas De Marchi wrote:
>>>On Wed, Dec 18, 2024 at 10:42:53AM +0530, Riana Tauro wrote:
>>>>Hi Lucas
>>>>
>>>>On 12/13/2024 11:28 AM, Lucas De Marchi wrote:
>>>>>On Thu, Nov 21, 2024 at 12:09:04PM +0530, Riana Tauro wrote:
>>>>>>PMU provides two counters (<engine>-busy-ticks-gt<n>,
>>>>>><engine>-total-ticks-gt<n>) to calculate engine busyness. 
>>>>>>When querying
>>>>>>engine busyness, user must group these 2 counters using the perf_event
>>>>>>group mechanism to ensure both counters are sampled together.
>>>>>>
>>>>>>To list engine busyness counters use the following
>>>>>>
>>>>>>./perf list
>>>>>> xe_0000_03_00.0/bcs0-busy-ticks-gt0/               [Kernel PMU event]
>>>>>
>>>>>this will need a rebase on latest versions of the pmu patches as we
>>>>>moved to have gt as a param rather than mangling the event name.
>>>>
>>>>In case of multiple gts, there might be different engines for each gt
>>>>So should we display a common name and unsupported in case the 
>>>>engine does not belong to the gt?
>>>>
>>>>sudo ./perf stat -e xe_0000_00_02.0/vcs0-busy-ticks,gt_id=0/ -I 1000
>>>
>>>why is engine not a param, like gt?
>Wouldn't it be better to have engine name in the event name? Otherwise 
>anyone using perf tool needs to find the engine class to name mapping
>
>@Umesh any inputs here?

sorry, I am not clear on how even gt_id is being passed here. How does 
the gt_id fit into the struct perf_event_attr {} that we pass as the 
event configuration? Are we using the config1/config2 fields to pass 
these additional params?

fwiu, whether we pass engine as a parameter or use the name in the 
event, we would still need to validate if the engine belongs to that gt.

Thanks,
Umesh

>>are you suggesting to have both engine and instance too as parameters?
>>Something like this?
>>
>>xe_0000_00_02.0/busy-ticks,engine_class=1,engine_instance=0,gt_id=0/
>>
>>
>>>
>>>Lucas De Marchi
>>
>