perf_counter tools: when no command is feed to perfstat, display help and exit
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/Documentation/perf_counter/kerneltop.c b/Documentation/perf_counter/kerneltop.c
index 0bd3c13..81a68aa 100644
--- a/Documentation/perf_counter/kerneltop.c
+++ b/Documentation/perf_counter/kerneltop.c
@@ -387,6 +387,9 @@
argc -= optind;
argv += optind;
+ if (!argc)
+ display_help();
+
/*
* Enable counters and exec the command:
*/