perf sched: Add 'perf sched trace', improve documentation

Alias 'perf sched trace' to 'perf trace', for workflow completeness.

Add a bit of documentation for perf sched.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

tools/perf/builtin-sched.c

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index ede40c1..8db0fd2 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -1597,7 +1597,7 @@
 }
 
 static const char * const sched_usage[] = {
-	"perf sched [<options>] {record|latency|replay}",
+	"perf sched [<options>] {record|latency|replay|trace}",
 	NULL
 };
 
@@ -1719,6 +1719,11 @@
 				usage_with_options(replay_usage, replay_options);
 		}
 		__cmd_replay();
+	} else if (!strcmp(argv[0], "trace")) {
+		/*
+		 * Aliased to 'perf trace' for now:
+		 */
+		return cmd_trace(argc, argv, prefix);
 	} else {
 		usage_with_options(sched_usage, sched_options);
 	}