diff options
| author | Tomas Glozar <tglozar@redhat.com> | 2025-01-23 15:23:36 +0100 |
|---|---|---|
| committer | Steven Rostedt (Google) <rostedt@goodmis.org> | 2025-01-24 13:46:16 -0500 |
| commit | d6fcd28ffeaaa6a1733303096637e6bf15704efb (patch) | |
| tree | aaa91f5e70192988844df28cee35f33ac612ad6f | |
| parent | b91cfd9f75c02e7f4463f8416d99138630c4dfd0 (diff) | |
rtla: Count missed trace events
Add function collect_missed_events to trace.c to act as a callback for
tracefs_follow_missed_events, summing the number of total missed events
into a new field missing_events of struct trace_instance.
In case record->missed_events is negative, trace->missed_events is set
to UINT64_MAX to signify an unknown number of events was missed.
The callback is activated on initialization of the trace instance.
Cc: John Kacur <jkacur@redhat.com>
Cc: Luis Goncalves <lgoncalv@redhat.com>
Cc: Gabriele Monaco <gmonaco@redhat.com>
Link: https://lore.kernel.org/20250123142339.990300-2-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
| -rw-r--r-- | tools/tracing/rtla/src/trace.c | 34 | ||||
| -rw-r--r-- | tools/tracing/rtla/src/trace.h | 1 |
2 files changed, 35 insertions, 0 deletions
diff --git a/tools/tracing/rtla/src/trace.c b/tools/tracing/rtla/src/trace.c index 80b14b8a3c2e..94e490782f14 100644 --- a/tools/tracing/rtla/src/trace.c +++ b/tools/tracing/rtla/src/trace.c @@ -127,6 +127,31 @@ collect_registered_events(struct tep_event *event, struct tep_record *record, } /* + * collect_missed_events - record number of missed events + * + * If rtla cannot keep up with events generated by tracer, events are going + * to fall out of the ring buffer. + * Collect how many events were missed so it can be reported to the user. + */ +static int +collect_missed_events(struct tep_event *event, struct tep_record *record, + int cpu, void *context) +{ + struct trace_instance *trace = context; + + if (trace->missed_events == UINT64_MAX) + return 0; + + if (record->missed_events > 0) + trace->missed_events += record->missed_events; + else + /* Events missed but no data on how many */ + trace->missed_events = UINT64_MAX; + + return 0; +} + +/* * trace_instance_destroy - destroy and free a rtla trace instance */ void trace_instance_destroy(struct trace_instance *trace) @@ -181,6 +206,15 @@ int trace_instance_init(struct trace_instance *trace, char *tool_name) */ tracefs_trace_off(trace->inst); + /* + * Collect the number of events missed due to tracefs buffer + * overflow. + */ + trace->missed_events = 0; + tracefs_follow_missed_events(trace->inst, + collect_missed_events, + trace); + return 0; out_err: diff --git a/tools/tracing/rtla/src/trace.h b/tools/tracing/rtla/src/trace.h index c3e03f7df770..a6e88709604b 100644 --- a/tools/tracing/rtla/src/trace.h +++ b/tools/tracing/rtla/src/trace.h @@ -17,6 +17,7 @@ struct trace_instance { struct tracefs_instance *inst; struct tep_handle *tep; struct trace_seq *seq; + unsigned long long missed_events; }; int trace_instance_init(struct trace_instance *trace, char *tool_name); |