perf report: Fix the output for stdio events list

Changing the output header for reporting forced groups via --groups
option on non grouped events, like:

  $ perf record -e 'cycles,instructions'
  $ perf report --stdio --group

Before:

  # Samples: 24  of event 'anon group { cycles:u, instructions:u }'

After:

  # Samples: 24  of events 'cycles:u, instructions:u'

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Fixes: ad52b8cb4886 ("perf report: Add support to display group output for non group events")
Link: http://lkml.kernel.org/r/20180307155020.32613-2-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 16 insertions, 4 deletions

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index e937894654b2..1ac8d9236efd 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -622,22 +622,34 @@ const char *perf_evsel__group_name(struct perf_evsel *evsel)
 	return evsel->group_name ?: "anon group";
 }
 
+/*
+ * Returns the group details for the specified leader,
+ * with following rules.
+ *
+ *  For record -e '{cycles,instructions}'
+ *    'anon group { cycles:u, instructions:u }'
+ *
+ *  For record -e 'cycles,instructions' and report --group
+ *    'cycles:u, instructions:u'
+ */
 int perf_evsel__group_desc(struct perf_evsel *evsel, char *buf, size_t size)
 {
-	int ret;
+	int ret = 0;
 	struct perf_evsel *pos;
 	const char *group_name = perf_evsel__group_name(evsel);
 
-	ret = scnprintf(buf, size, "%s", group_name);
+	if (!evsel->forced_leader)
+		ret = scnprintf(buf, size, "%s { ", group_name);
 
-	ret += scnprintf(buf + ret, size - ret, " { %s",
+	ret += scnprintf(buf + ret, size - ret, "%s",
 			 perf_evsel__name(evsel));
 
 	for_each_group_member(pos, evsel)
 		ret += scnprintf(buf + ret, size - ret, ", %s",
 				 perf_evsel__name(pos));
 
-	ret += scnprintf(buf + ret, size - ret, " }");
+	if (!evsel->forced_leader)
+		ret += scnprintf(buf + ret, size - ret, " }");
 
 	return ret;
 }