perf evsel: Add iterator to iterate over events ordered by CPU

Add some common code that is needed to iterate over all events
in CPU order. Used in followon patches

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: http://lore.kernel.org/lkml/20191121001522.180827-6-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/evlist.c

@@ -342,6 +342,38 @@ static int perf_evlist__nr_threads(struct evlist *evlist,
 		return perf_thread_map__nr(evlist->core.threads);
 }
 
+void evlist__cpu_iter_start(struct evlist *evlist)
+{
+	struct evsel *pos;
+
+	/*
+	 * Reset the per evsel cpu_iter. This is needed because
+	 * each evsel's cpumap may have a different index space,
+	 * and some operations need the index to modify
+	 * the FD xyarray (e.g. open, close)
+	 */
+	evlist__for_each_entry(evlist, pos)
+		pos->cpu_iter = 0;
+}
+
+bool evsel__cpu_iter_skip_no_inc(struct evsel *ev, int cpu)
+{
+	if (ev->cpu_iter >= ev->core.cpus->nr)
+		return true;
+	if (cpu >= 0 && ev->core.cpus->map[ev->cpu_iter] != cpu)
+		return true;
+	return false;
+}
+
+bool evsel__cpu_iter_skip(struct evsel *ev, int cpu)
+{
+	if (!evsel__cpu_iter_skip_no_inc(ev, cpu)) {
+		ev->cpu_iter++;
+		return false;
+	}
+	return true;
+}
+
 void evlist__disable(struct evlist *evlist)
 {
 	struct evsel *pos;