Re: [PATCH v6 1/7] perf evlist: Add perf_evlist__go_system_wide() helper

[Yang Jihong <yangjihong1@huawei.com>]

Hello,

On 2023/8/25 12:51, Ian Rogers wrote:
> On Sun, Aug 20, 2023 at 6:30 PM Yang Jihong <yangjihong1@huawei.com> wrote:
>>
>> For dummy events that keep tracking, we may need to modify its cpu_maps.
>> For example, change the cpu_maps to record sideband events for all CPUS.
>> Add perf_evlist__go_system_wide() helper to support this scenario.
>>
>> Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
>> Acked-by: Adrian Hunter <adrian.hunter@intel.com>
>> ---
>>   tools/lib/perf/evlist.c                  | 9 +++++++++
>>   tools/lib/perf/include/internal/evlist.h | 2 ++
>>   2 files changed, 11 insertions(+)
>>
>> diff --git a/tools/lib/perf/evlist.c b/tools/lib/perf/evlist.c
>> index b8b066d0dc5e..3acbbccc1901 100644
>> --- a/tools/lib/perf/evlist.c
>> +++ b/tools/lib/perf/evlist.c
>> @@ -738,3 +738,12 @@ int perf_evlist__nr_groups(struct perf_evlist *evlist)
>>          }
>>          return nr_groups;
>>   }
>> +
>> +void perf_evlist__go_system_wide(struct perf_evlist *evlist, struct perf_evsel *evsel)
>> +{
>> +       if (!evsel->system_wide) {
>> +               evsel->system_wide = true;
>> +               if (evlist->needs_map_propagation)
>> +                       __perf_evlist__propagate_maps(evlist, evsel);
>> +       }
>> +}
> 
> I think this should be:
> 
> void evsel__set_system_wide(struct evsel *evsel)
> {
>          if (evsel->system_wide)
>                 return;
>          evsel->system_wide = true;
>          if (evsel->evlist->core.needs_map_propagation)
> ...
> 
> The API being on evlist makes it look like all evsels are affected.
> 
This part of the code is implemented according to Adrian's suggestion.
Refer to:

https://lore.kernel.org/linux-perf-users/206972a3-d44d-1c75-3fbc-426427614543@intel.com/

The logic of both is the same, and either is OK for me.
If really want to change it, please let me know.

Thanks,
Yang