[PATCH v2 5/6] perf tool: Allow system-wide 'perf stat' without 'command'

[Lin Ming <ming.m.lin@intel.com>]

There are package level counters, for example Intel uncore counters,
can't be limited to process. So we should allow 'perf stat' to run without 'command'.

$ sudo perf stat -a -C 0 -e uncore:cycle
^C
 Performance counter stats for 'CPU 0':

        56,547,314 uncore:cycle

Signed-off-by: Lin Ming <ming.m.lin@intel.com>
---
 tools/perf/builtin-stat.c |   11 +++++++++--
 1 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 1d08c80..84546ff 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -958,7 +958,14 @@ static void print_stat(int argc, const char **argv)
 	if (!csv_output) {
 		fprintf(stderr, "\n");
 		fprintf(stderr, " Performance counter stats for ");
-		if(target_pid == -1 && target_tid == -1) {
+		if (system_wide) {
+			fprintf(stderr, "\'CPU ");
+			for (i = 0; i < evsel_list->cpus->nr; i++) {
+				fprintf(stderr, "%d", evsel_list->cpus->map[i]);
+				if (i < evsel_list->cpus->nr - 1)
+					fprintf(stderr, ",");
+			}
+		} else if (target_pid == -1 && target_tid == -1) {
 			fprintf(stderr, "\'%s", argv[0]);
 			for (i = 1; i < argc; i++)
 				fprintf(stderr, " %s", argv[i]);
@@ -1166,7 +1173,7 @@ int cmd_stat(int argc, const char **argv, const char *prefix __used)
 	} else if (big_num_opt == 0) /* User passed --no-big-num */
 		big_num = false;
 
-	if (!argc && target_pid == -1 && target_tid == -1)
+	if (!system_wide && !argc && target_pid == -1 && target_tid == -1)
 		usage_with_options(stat_usage, options);
 	if (run_count <= 0)
 		usage_with_options(stat_usage, options);
-- 
1.7.5.1