perf evlist: Add perf_evlist__set_tracking_event()

Add a function to change which event is used to track mmap, comm and
task events.

This is needed with Instruction Tracing because the Instruction Tracing
event must come first but cannot be used for tracking because it will be
disabled under some circumstances.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1406786474-9306-10-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/evlist.c

@@ -122,6 +122,7 @@ void perf_evlist__add(struct perf_evlist *evlist, struct perf_evsel *entry)
 {
 	list_add_tail(&entry->node, &evlist->entries);
 	entry->idx = evlist->nr_entries;
+	entry->tracking = !entry->idx;
 
 	if (!evlist->nr_entries++)
 		perf_evlist__set_id_pos(evlist);
@@ -1295,3 +1296,19 @@ void perf_evlist__to_front(struct perf_evlist *evlist,
 
 	list_splice(&move, &evlist->entries);
 }
+
+void perf_evlist__set_tracking_event(struct perf_evlist *evlist,
+				     struct perf_evsel *tracking_evsel)
+{
+	struct perf_evsel *evsel;
+
+	if (tracking_evsel->tracking)
+		return;
+
+	evlist__for_each(evlist, evsel) {
+		if (evsel != tracking_evsel)
+			evsel->tracking = false;
+	}
+
+	tracking_evsel->tracking = true;
+}

tools/perf/util/evlist.h

@@ -262,4 +262,7 @@ void perf_evlist__to_front(struct perf_evlist *evlist,
 #define evlist__for_each_safe(evlist, tmp, evsel) \
 	__evlist__for_each_safe(&(evlist)->entries, tmp, evsel)
 
+void perf_evlist__set_tracking_event(struct perf_evlist *evlist,
+				     struct perf_evsel *tracking_evsel);
+
 #endif /* __PERF_EVLIST_H */

tools/perf/util/evsel.c

@@ -162,6 +162,7 @@ void perf_evsel__init(struct perf_evsel *evsel,
 		      struct perf_event_attr *attr, int idx)
 {
 	evsel->idx	   = idx;
+	evsel->tracking	   = !idx;
 	evsel->attr	   = *attr;
 	evsel->leader	   = evsel;
 	evsel->unit	   = "";
@@ -561,7 +562,7 @@ void perf_evsel__config(struct perf_evsel *evsel, struct record_opts *opts)
 {
 	struct perf_evsel *leader = evsel->leader;
 	struct perf_event_attr *attr = &evsel->attr;
-	int track = !evsel->idx; /* only the first counter needs these */
+	int track = evsel->tracking;
 	bool per_cpu = opts->target.default_per_cpu && !opts->target.per_thread;
 
 	attr->sample_id_all = perf_missing_features.sample_id_all ? 0 : 1;

tools/perf/util/evsel.h

@@ -86,6 +86,7 @@ struct perf_evsel {
 	bool			no_aux_samples;
 	bool			immediate;
 	bool			system_wide;
+	bool			tracking;
 	/* parse modifier helper */
 	int			exclude_GH;
 	int			nr_members;

tools/perf/util/record.c

@@ -115,7 +115,7 @@ void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts)
 
 	evlist__for_each(evlist, evsel) {
 		perf_evsel__config(evsel, opts);
-		if (!evsel->idx && use_comm_exec)
+		if (evsel->tracking && use_comm_exec)
 			evsel->attr.comm_exec = 1;
 	}