perf: Report lost events in perf trace debug mode
Account and report lost events in perf trace debugging mode,
useful to check the reliability of the traces.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 83df8db4..294da72 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -11,7 +11,7 @@
static char const *script_name;
static char const *generate_script_lang;
-static bool debug_ordering;
+static bool debug_mode;
static u64 last_timestamp;
static u64 nr_unordered;
@@ -92,7 +92,7 @@
}
if (session->sample_type & PERF_SAMPLE_RAW) {
- if (debug_ordering) {
+ if (debug_mode) {
if (data.time < last_timestamp) {
pr_err("Samples misordered, previous: %llu "
"this: %llu\n", last_timestamp,
@@ -116,6 +116,15 @@
return 0;
}
+static u64 nr_lost;
+
+static int process_lost_event(event_t *event, struct perf_session *session __used)
+{
+ nr_lost += event->lost.lost;
+
+ return 0;
+}
+
static struct perf_event_ops event_ops = {
.sample = process_sample_event,
.comm = event__process_comm,
@@ -123,6 +132,7 @@
.event_type = event__process_event_type,
.tracing_data = event__process_tracing_data,
.build_id = event__process_build_id,
+ .lost = process_lost_event,
.ordered_samples = true,
};
@@ -141,8 +151,10 @@
ret = perf_session__process_events(session, &event_ops);
- if (debug_ordering)
+ if (debug_mode) {
pr_err("Misordered timestamps: %llu\n", nr_unordered);
+ pr_err("Lost events: %llu\n", nr_lost);
+ }
return ret;
}
@@ -554,8 +566,8 @@
"generate perf-trace.xx script in specified language"),
OPT_STRING('i', "input", &input_name, "file",
"input file name"),
- OPT_BOOLEAN('d', "debug-ordering", &debug_ordering,
- "check that samples time ordering is monotonic"),
+ OPT_BOOLEAN('d', "debug-mode", &debug_mode,
+ "do various checks like samples ordering and lost events"),
OPT_END()
};