1 files changed, 18 insertions, 0 deletions

diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 3d5604739493..3ae69550fa0b 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -852,6 +852,24 @@ done:
         flush_sample_queue(self, ops);
 out_err:
         ui_progress__delete(progress);
+
+        if (ops->lost == event__process_lost &&
+            self->hists.stats.total_lost != 0) {
+                ui__warning("Processed %Lu events and LOST %Lu!\n\n"
+                            "Check IO/CPU overload!\n\n",
+                            self->hists.stats.total_period,
+                            self->hists.stats.total_lost);
+        }
+        
+        if (self->hists.stats.nr_unknown_events != 0) {
+                ui__warning("Found %u unknown events!\n\n"
+                            "Is this an older tool processing a perf.data "
+                            "file generated by a more recent tool?\n\n"
+                            "If that is not the case, consider "
+                            "reporting to linux-kernel@vger.kernel.org.\n\n",
+                            self->hists.stats.nr_unknown_events);
+        }
+                
         return err;
 }