perf report: Tell the user when a perf.data file has no samples

[root@emilia ~]# perf report --stdio
The perf.data file has no samples!
[root@emilia ~]#

The TUI shows a popup warning message with the same message.

Reported-by: Ingo Molnar <mingo@elte.hu>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index f9a99a1ce609..dddcc7ea2bec 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -350,6 +350,12 @@ static int __cmd_report(void)
                 perf_session__fprintf_dsos(session, stdout);
 
         next = rb_first(&session->hists_tree);
+
+        if (next == NULL) {
+                ui__warning("The %s file has no samples!\n", input_name);
+                goto out_delete;
+        }
+
         while (next) {
                 struct hists *hists;