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Message-ID: <20240820154504.128923-2-namhyung@kernel.org>
Date: Tue, 20 Aug 2024 08:45:03 -0700
From: Namhyung Kim <namhyung@...nel.org>
To: Arnaldo Carvalho de Melo <acme@...nel.org>,
Ian Rogers <irogers@...gle.com>,
Kan Liang <kan.liang@...ux.intel.com>
Cc: Jiri Olsa <jolsa@...nel.org>,
Adrian Hunter <adrian.hunter@...el.com>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...nel.org>,
LKML <linux-kernel@...r.kernel.org>,
linux-perf-users@...r.kernel.org,
KP Singh <kpsingh@...nel.org>,
Song Liu <song@...nel.org>,
bpf@...r.kernel.org
Subject: [PATCH v3 2/3] 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: Namhyung Kim <namhyung@...nel.org>
---
tools/perf/builtin-report.c | 9 +++++++--
tools/perf/ui/stdio/hist.c | 4 ++--
tools/perf/util/events_stats.h | 15 ++++++++++++++-
tools/perf/util/hist.c | 19 +++++++++++++++----
tools/perf/util/hist.h | 1 +
tools/perf/util/machine.c | 5 +++--
tools/perf/util/session.c | 5 +++--
7 files changed, 45 insertions(+), 13 deletions(-)
diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index 1643113616f4..c304d9b06190 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -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;
}
diff --git a/tools/perf/ui/stdio/hist.c b/tools/perf/ui/stdio/hist.c
index 9372e8904d22..74b2c619c56c 100644
--- a/tools/perf/ui/stdio/hist.c
+++ b/tools/perf/ui/stdio/hist.c
@@ -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]);
}
}
diff --git a/tools/perf/util/events_stats.h b/tools/perf/util/events_stats.h
index f43e5b1a366a..eabd7913c309 100644
--- a/tools/perf/util/events_stats.h
+++ b/tools/perf/util/events_stats.h
@@ -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);
diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
index 0f9ce2ee2c31..dadce2889e52 100644
--- a/tools/perf/util/hist.c
+++ b/tools/perf/util/hist.c
@@ -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;
diff --git a/tools/perf/util/hist.h b/tools/perf/util/hist.h
index 30c13fc8cbe4..4ea247e54fb6 100644
--- a/tools/perf/util/hist.h
+++ b/tools/perf/util/hist.h
@@ -371,6 +371,7 @@ 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,
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index c08774d06d14..00a49d0744fc 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -642,8 +642,9 @@ int machine__process_lost_event(struct machine *machine __maybe_unused,
int machine__process_lost_samples_event(struct machine *machine __maybe_unused,
union perf_event *event, struct perf_sample *sample)
{
- dump_printf(": id:%" PRIu64 ": lost samples :%" PRI_lu64 "\n",
- sample->id, event->lost_samples.lost);
+ dump_printf(": id:%" PRIu64 ": lost samples :%" PRI_lu64 "%s\n",
+ sample->id, event->lost_samples.lost,
+ event->header.misc & PERF_RECORD_MISC_LOST_SAMPLES_BPF ? " (BPF)" : "");
return 0;
}
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index d2bd563119bc..774eb3382000 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1290,8 +1290,9 @@ static int machines__deliver_event(struct machines *machines,
evlist->stats.total_lost += event->lost.lost;
return tool->lost(tool, event, sample, machine);
case PERF_RECORD_LOST_SAMPLES:
- if (tool->lost_samples == perf_event__process_lost_samples &&
- !(event->header.misc & PERF_RECORD_MISC_LOST_SAMPLES_BPF))
+ if (event->header.misc & PERF_RECORD_MISC_LOST_SAMPLES_BPF)
+ evlist->stats.total_dropped_samples += event->lost_samples.lost;
+ else if (tool->lost_samples == perf_event__process_lost_samples)
evlist->stats.total_lost_samples += event->lost_samples.lost;
return tool->lost_samples(tool, event, sample, machine);
case PERF_RECORD_READ:
--
2.46.0.184.g6999bdac58-goog
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