perf parse-events: Don't reorder ungrouped events by PMU

The pmu_group_name by default returns "cpu" which on non-hybrid/ARM
means that ungrouped software, and hardware events are all going to
sort by the original insertion index.

However, on hybrid and ARM wildcard expansion may mean the PMU name is
set and events will be unnecessarily reordered - triggering the
reordering warning.
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Kan Liang <kan.liang@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ahmad Yasin <ahmad.yasin@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Caleb Biggers <caleb.biggers@intel.com>
Cc: Edward Baker <edward.baker@intel.com>
Cc: Florian Fischer <florian.fischer@muhq.space>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kang Minchul <tegongkang@gmail.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Perry Taylor <perry.taylor@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Samantha Alt <samantha.alt@intel.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: Weilin Wang <weilin.wang@intel.com>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Cc: Yang Jihong <yangjihong1@huawei.com>
Link: https://lore.kernel.org/r/20230502223851.2234828-5-irogers@google.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/parse-events.c

@@ -2140,25 +2140,32 @@ static int evlist__cmp(void *state, const struct list_head *l, const struct list
 	int *leader_idx = state;
 	int lhs_leader_idx = *leader_idx, rhs_leader_idx = *leader_idx, ret;
 	const char *lhs_pmu_name, *rhs_pmu_name;
+	bool lhs_has_group = false, rhs_has_group = false;
 
 	/*
 	 * First sort by grouping/leader. Read the leader idx only if the evsel
 	 * is part of a group, as -1 indicates no group.
 	 */
-	if (lhs_core->leader != lhs_core || lhs_core->nr_members > 1)
+	if (lhs_core->leader != lhs_core || lhs_core->nr_members > 1) {
+		lhs_has_group = true;
 		lhs_leader_idx = lhs_core->leader->idx;
-	if (rhs_core->leader != rhs_core || rhs_core->nr_members > 1)
+	}
+	if (rhs_core->leader != rhs_core || rhs_core->nr_members > 1) {
+		rhs_has_group = true;
 		rhs_leader_idx = rhs_core->leader->idx;
+	}
 
 	if (lhs_leader_idx != rhs_leader_idx)
 		return lhs_leader_idx - rhs_leader_idx;
 
-	/* Group by PMU. Groups can't span PMUs. */
-	lhs_pmu_name = evsel__group_pmu_name(lhs);
-	rhs_pmu_name = evsel__group_pmu_name(rhs);
-	ret = strcmp(lhs_pmu_name, rhs_pmu_name);
-	if (ret)
-		return ret;
+	/* Group by PMU if there is a group. Groups can't span PMUs. */
+	if (lhs_has_group && rhs_has_group) {
+		lhs_pmu_name = evsel__group_pmu_name(lhs);
+		rhs_pmu_name = evsel__group_pmu_name(rhs);
+		ret = strcmp(lhs_pmu_name, rhs_pmu_name);
+		if (ret)
+			return ret;
+	}
 
 	/* Architecture specific sorting. */
 	return arch_evlist__cmp(lhs, rhs);