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 <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/event.h

···
 	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

···
 	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);
···
 				    stats->nr_events[PERF_RECORD_SAMPLE] + stats->total_lost_samples,
 				    drop_rate * 100.0);
 		}
+	}
+
+	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) {