perf evsel: Add function to compute group PMU name

The computed name respects software events and aux event groups, such
that the pmu_name is changed to be that of the aux event leader or
group leader for software events. This is done as a later change will
split events that are in different PMUs into different groups.

Committer notes:

Added a stub for this new function so that 'perf test python' passes.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.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: Kan Liang <kan.liang@linux.intel.com>
Cc: Kim Phillips <kim.phillips@amd.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Steinar H. Gunderson <sesse@google.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Link: https://lore.kernel.org/r/20230312021543.3060328-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 24 insertions, 0 deletions

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 798f072b2763..3dda8a25cf50 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -821,6 +821,30 @@ out_unknown:
 	return "unknown";
 }
 
+const char *evsel__group_pmu_name(const struct evsel *evsel)
+{
+	const struct evsel *leader;
+
+	/* If the pmu_name is set use it. pmu_name isn't set for CPU and software events. */
+	if (evsel->pmu_name)
+		return evsel->pmu_name;
+	/*
+	 * Software events may be in a group with other uncore PMU events. Use
+	 * the pmu_name of the group leader to avoid breaking the software event
+	 * out of the group.
+	 *
+	 * Aux event leaders, like intel_pt, expect a group with events from
+	 * other PMUs, so substitute the AUX event's PMU in this case.
+	 */
+	leader  = evsel__leader(evsel);
+	if ((evsel->core.attr.type == PERF_TYPE_SOFTWARE || evsel__is_aux_event(leader)) &&
+	    leader->pmu_name) {
+		return leader->pmu_name;
+	}
+
+	return "cpu";
+}
+
 const char *evsel__metric_id(const struct evsel *evsel)
 {
 	if (evsel->metric_id)