perf tools: Fix lost and unknown events handling

Fix it by explaining what can be happening and giving the number of processed
and lost events.

Also holler if unknown events were found, that can be due to processing a
perf.data file collected using a newer tool where newer events got added on
reporting using an older perf tool, that or a bug, so ask for a report to be
made.

Works on both --tui and --stdio.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

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;
 }