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SubjectRe: [V4 PATCH] perf parse-events: Specially handle uncore event alias in small groups
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>> +static int
>> +parse_events__set_leader_for_uncore_aliase(char *name, struct list_head *list,
>> + struct parse_events_state *parse_state)
>> +{
>> + struct perf_evsel *evsel, *leader;
>> + uintptr_t *leaders;
>> + bool is_leader = true;
>> + int i, nr_pmu = 0, total_members, ret = 0;
>> +
>> + leader = list_first_entry(list, struct perf_evsel, node);
>> + evsel = list_last_entry(list, struct perf_evsel, node);
>> + total_members = evsel->idx - leader->idx + 1;
>> +
>> + leaders = calloc(total_members, sizeof(uintptr_t));
>> + if (!leaders)
>> + return 0;
>
> I see.. I meant we should return -ENOMEM in here, but
> we don't check it in the called anyway.. so perhaps
>
> if (WARN_ON(!leaders))
> return 0;
>

Sure. I will change it in V5.

>
>> +
>> + __evlist__for_each_entry(list, evsel) {
>> +
>> + /* Only split the uncore group which members use alias */
>> + if (!evsel->use_uncore_alias)
>> + goto out;
>> +
>> + /* The events must be from the same uncore block */
>> + if (!is_same_uncore_block(leader->pmu_name, evsel->pmu_name))
>> + goto out;
>> +
>> + if (!is_leader)
>> + continue;
>> + /*
>> + * If the event's PMU name starts to repeat, it must be a new
>> + * event. That can be used to distinguish the leader from
>> + * other members, even they have the same event name.
>> + */
>> + if ((leader != evsel) && (leader->pmu_name == evsel->pmu_name)) {
>> + is_leader = false;
>> + continue;
>> + }
>
> I still don't get why you don't 'break' in here.. you set is_leader to false,
> then the loop will never get pass the !is_leader condition above
>

All the members must use alias, and be from the same uncore block.
We have to go through the whole group to check the events.

Thanks,
Kan

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