Commit 1a5474a7 authored by Namhyung Kim's avatar Namhyung Kim Committed by Arnaldo Carvalho de Melo
Browse files

perf tools: Print lost samples due to BPF filter 



Print the actual dropped sample count in the event stat.

  $ sudo perf record -o- -e cycles --filter 'period < 10000' \
      -e instructions --filter 'ip > 0x8000000000000000' perf test -w noploop | \
      perf report --stat -i-
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.058 MB - ]

  Aggregated stats:
                 TOTAL events:        469
                  MMAP events:        268  (57.1%)
                  COMM events:          2  ( 0.4%)
                  EXIT events:          1  ( 0.2%)
                SAMPLE events:         16  ( 3.4%)
                 MMAP2 events:         22  ( 4.7%)
          LOST_SAMPLES events:          2  ( 0.4%)
               KSYMBOL events:         89  (19.0%)
             BPF_EVENT events:         39  ( 8.3%)
                  ATTR events:          2  ( 0.4%)
        FINISHED_ROUND events:          1  ( 0.2%)
              ID_INDEX events:          1  ( 0.2%)
            THREAD_MAP events:          1  ( 0.2%)
               CPU_MAP events:          1  ( 0.2%)
          EVENT_UPDATE events:          2  ( 0.4%)
             TIME_CONV events:          1  ( 0.2%)
               FEATURE events:         20  ( 4.3%)
         FINISHED_INIT events:          1  ( 0.2%)
  cycles stats:
                SAMPLE events:          2
    LOST_SAMPLES (BPF) events:       4010
  instructions stats:
                SAMPLE events:         14
    LOST_SAMPLES (BPF) events:       3990

Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20240820154504.128923-2-namhyung@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 0fe2b18d

tools/perf/builtin-report.c

+7 −2
Original line number Diff line number Diff line
@@ -795,8 +795,13 @@ static int count_lost_samples_event(const struct perf_tool *tool, 


	evsel = evlist__id2evsel(rep->session->evlist, sample->id);

	if (evsel) {

		hists__inc_nr_lost_samples(evsel__hists(evsel),

					   event->lost_samples.lost);

		struct hists *hists = evsel__hists(evsel);

		u32 count = event->lost_samples.lost;



		if (event->header.misc & PERF_RECORD_MISC_LOST_SAMPLES_BPF)

			hists__inc_nr_dropped_samples(hists, count);

		else

			hists__inc_nr_lost_samples(hists, count);

	}

	return 0;

}

tools/perf/ui/stdio/hist.c

+2 −2
Original line number Diff line number Diff line
@@ -913,11 +913,11 @@ size_t events_stats__fprintf(struct events_stats *stats, FILE *fp) 
			continue;



		if (i && total) {

			ret += fprintf(fp, "%16s events: %10d  (%4.1f%%)\n",

			ret += fprintf(fp, "%20s events: %10d  (%4.1f%%)\n",

				       name, stats->nr_events[i],

				       100.0 * stats->nr_events[i] / total);

		} else {

			ret += fprintf(fp, "%16s events: %10d\n",

			ret += fprintf(fp, "%20s events: %10d\n",

				       name, stats->nr_events[i]);

		}

	}

tools/perf/util/events_stats.h

+14 −1
Original line number Diff line number Diff line
@@ -18,7 +18,18 @@ 
 * PERF_RECORD_LOST_SAMPLES event. The number of lost-samples events is stored

 * in .nr_events[PERF_RECORD_LOST_SAMPLES] while total_lost_samples tells

 * exactly how many samples the kernel in fact dropped, i.e. it is the sum of

 * all struct perf_record_lost_samples.lost fields reported.

 * all struct perf_record_lost_samples.lost fields reported without setting the

 * misc field in the header.

 *

 * The BPF program can discard samples according to the filter expressions given

 * by the user.  This number is kept in a BPF map and dumped at the end of perf

 * record in a PERF_RECORD_LOST_SAMPLES event.  To differentiate it from other

 * lost samples, perf tools sets PERF_RECORD_MISC_LOST_SAMPLES_BPF flag in the

 * header.misc field.  The number of dropped-samples events is stored in

 * .nr_events[PERF_RECORD_LOST_SAMPLES] while total_dropped_samples tells

 * exactly how many samples the BPF program in fact dropped, i.e. it is the sum

 * of all struct perf_record_lost_samples.lost fields reported with the misc

 * field set in the header.

 *

 * The total_period is needed because by default auto-freq is used, so

 * multiplying nr_events[PERF_EVENT_SAMPLE] by a frequency isn't possible to get
@@ -28,6 +39,7 @@ 
struct events_stats {

	u64 total_lost;

	u64 total_lost_samples;

	u64 total_dropped_samples;

	u64 total_aux_lost;

	u64 total_aux_partial;

	u64 total_aux_collision;
@@ -48,6 +60,7 @@ struct hists_stats { 
	u32 nr_samples;

	u32 nr_non_filtered_samples;

	u32 nr_lost_samples;

	u32 nr_dropped_samples;

};



void events_stats__inc(struct events_stats *stats, u32 type);

tools/perf/util/hist.c

+15 −4
Original line number Diff line number Diff line
@@ -2385,6 +2385,11 @@ void hists__inc_nr_lost_samples(struct hists *hists, u32 lost) 
	hists->stats.nr_lost_samples += lost;

}



void hists__inc_nr_dropped_samples(struct hists *hists, u32 lost)

{

	hists->stats.nr_dropped_samples += lost;

}



static struct hist_entry *hists__add_dummy_entry(struct hists *hists,

						 struct hist_entry *pair)

{
@@ -2729,18 +2734,24 @@ size_t evlist__fprintf_nr_events(struct evlist *evlist, FILE *fp) 


	evlist__for_each_entry(evlist, pos) {

		struct hists *hists = evsel__hists(pos);

		u64 total_samples = hists->stats.nr_samples;



		total_samples += hists->stats.nr_lost_samples;

		total_samples += hists->stats.nr_dropped_samples;



		if (symbol_conf.skip_empty && !hists->stats.nr_samples &&

		    !hists->stats.nr_lost_samples)

		if (symbol_conf.skip_empty && total_samples == 0)

			continue;



		ret += fprintf(fp, "%s stats:\n", evsel__name(pos));

		if (hists->stats.nr_samples)

			ret += fprintf(fp, "%16s events: %10d\n",

			ret += fprintf(fp, "%20s events: %10d\n",

				       "SAMPLE", hists->stats.nr_samples);

		if (hists->stats.nr_lost_samples)

			ret += fprintf(fp, "%16s events: %10d\n",

			ret += fprintf(fp, "%20s events: %10d\n",

				       "LOST_SAMPLES", hists->stats.nr_lost_samples);

		if (hists->stats.nr_dropped_samples)

			ret += fprintf(fp, "%20s events: %10d\n",

				       "LOST_SAMPLES (BPF)", hists->stats.nr_dropped_samples);

	}



	return ret;

tools/perf/util/hist.h

+1 −0
Original line number Diff line number Diff line
@@ -372,6 +372,7 @@ void hists__inc_stats(struct hists *hists, struct hist_entry *h); 
void hists__inc_nr_events(struct hists *hists);

void hists__inc_nr_samples(struct hists *hists, bool filtered);

void hists__inc_nr_lost_samples(struct hists *hists, u32 lost);

void hists__inc_nr_dropped_samples(struct hists *hists, u32 lost);



size_t hists__fprintf(struct hists *hists, bool show_header, int max_rows,

		      int max_cols, float min_pcnt, FILE *fp,