perf session: Warn when AUX data has been lost

By default 'perf record' will postprocess the perf.data file to
determine build-ids.  When that happens, the number of lost perf events
is displayed.

Make that also happen for AUX events.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1443186956-18718-7-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/event.h

@@ -257,6 +257,7 @@ struct events_stats {
 	u64 total_non_filtered_period;
 	u64 total_lost;
 	u64 total_lost_samples;
+	u64 total_aux_lost;
 	u64 total_invalid_chains;
 	u32 nr_events[PERF_RECORD_HEADER_MAX];
 	u32 nr_non_filtered_samples;

tools/perf/util/session.c

@@ -1101,6 +1101,9 @@ static int machines__deliver_event(struct machines *machines,
 	case PERF_RECORD_UNTHROTTLE:
 		return tool->unthrottle(tool, event, sample, machine);
 	case PERF_RECORD_AUX:
+		if (tool->aux == perf_event__process_aux &&
+		    (event->aux.flags & PERF_AUX_FLAG_TRUNCATED))
+			evlist->stats.total_aux_lost += 1;
 		return tool->aux(tool, event, sample, machine);
 	case PERF_RECORD_ITRACE_START:
 		return tool->itrace_start(tool, event, sample, machine);
@@ -1346,6 +1349,13 @@ static void perf_session__warn_about_errors(const struct perf_session *session)
 		}
 	}
 
+	if (session->tool->aux == perf_event__process_aux &&
+	    stats->total_aux_lost != 0) {
+		ui__warning("AUX data lost %" PRIu64 " times out of %u!\n\n",
+			    stats->total_aux_lost,
+			    stats->nr_events[PERF_RECORD_AUX]);
+	}
+
 	if (stats->nr_unknown_events != 0) {
 		ui__warning("Found %u unknown events!\n\n"
 			    "Is this an older tool processing a perf.data "