perf list: Add usage

Currently 'perf list' is not very helpful if you forget the syntax:

  $ perf list -h

  List of pre-defined events (to be used in -e):

After:
  $ perf list -h

   usage: perf list [hw|sw|cache|tracepoint|pmu|event_glob]

Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/527133AD.4030003@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-list.c b/tools/perf/builtin-list.c
index 45000e7d4398baceaa04130a38ffb9f2cb3492a0..011195e38f2173947550100e62927e908b429d30 100644 (file)
--- a/tools/perf/builtin-list.c
+++ b/tools/perf/builtin-list.c
@@ -14,20 +14,31 @@
 #include "util/parse-events.h"
 #include "util/cache.h"
 #include "util/pmu.h"
+#include "util/parse-options.h"
 
 int cmd_list(int argc, const char **argv, const char *prefix __maybe_unused)
 {
        int i;
+       const struct option list_options[] = {
+               OPT_END()
+       };
+       const char * const list_usage[] = {
+               "perf list [hw|sw|cache|tracepoint|pmu|event_glob]",
+               NULL
+       };
+
+       argc = parse_options(argc, argv, list_options, list_usage,
+                            PARSE_OPT_STOP_AT_NON_OPTION);
 
        setup_pager();
 
-       if (argc == 1) {
+       if (argc == 0) {
                print_events(NULL, false);
                return 0;
        }
 
-       for (i = 1; i < argc; ++i) {
-               if (i > 2)
+       for (i = 0; i < argc; ++i) {
+               if (i)
                        putchar('\n');
                if (strncmp(argv[i], "tracepoint", 10) == 0)
                        print_tracepoint_events(NULL, NULL, false);