On Wed, Apr 25, 2018 at 10:58:43AM -0700, kan.li...@linux.intel.com wrote:
SNIP
> -void parse_events__set_leader(char *name, struct list_head *list)
> +/*
> + * Check if the two uncore PMUs are from the same uncore block
> + * The format of the uncore PMU name is uncore_#blockname_#pmuidx
> + */
> +static bool is_same_uncore_block(const char *pmu_name_a, const char
> *pmu_name_b)
> +{
> + char *end_a, *end_b;
> +
> + end_a = strrchr(pmu_name_a, '_');
> + end_b = strrchr(pmu_name_b, '_');
> +
> + if (!end_a || !end_b)
> + return false;
> +
> + if ((end_a - pmu_name_a) != (end_b - pmu_name_b))
> + return false;
> +
> + return (strncmp(pmu_name_a, pmu_name_b, end_a - pmu_name_a) == 0);
> +}
> +
> +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 = 0, nr_pmu = 0, total_members, ret = 0;
> +
> + leader = list_entry(list->next, struct perf_evsel, node);
> + evsel = list_entry(list->prev, struct perf_evsel, node);
could you please use list_last_entry and list_first_entry in here?
> + total_members = evsel->idx - leader->idx + 1;
> +
> + leaders = calloc(total_members, sizeof(uintptr_t));
> + if (!leaders)
> + return ret;
returns 0 in here
> +
> + __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;
setting "is_leader = false" basically breaks the loop,
because of that !leader check above, so why continue?
> + continue;
> + }
> + /* The name is always alias name */
> + WARN_ON(strcmp(leader->name, evsel->name));
> +
> + leaders[nr_pmu++] = (uintptr_t) evsel;
> + }
> +
> + /* only one event alias */
> + if (nr_pmu == total_members) {
> + parse_state->nr_groups--;
> + goto handled;
> + }
> +
> + __evlist__for_each_entry(list, evsel) {
> + if (i >= nr_pmu)
> + i = 0;
> + evsel->leader = (struct perf_evsel *) leaders[i++];
> + }
it's not so obvious from the code how the groups
are set.. please describe that logic in the comment
thanks,
jirka
> +
> + for (i = 0; i < nr_pmu; i++) {
> + evsel = (struct perf_evsel *) leaders[i];
> + evsel->nr_members = total_members / nr_pmu;
> + evsel->group_name = name ? strdup(name) : NULL;
> + }
> +
> + parse_state->nr_groups += nr_pmu - 1;
> +
> +handled:
> + ret = 1;
> +out:
> + free(leaders);
> + return ret;
> +}
