[PATCH 4/4] perf tools: Support reading PERF_FORMAT_LOST

From: Namhyung Kim
Date: Mon Aug 15 2022 - 16:32:55 EST

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The recent kernel added lost count can be read from either read(2) or
ring buffer data with PERF_SAMPLE_READ. As it's a variable length data
we need to access it according to the format info.

But for perf tools use cases, PERF_FORMAT_ID is always set. So we can
only check PERF_FORMAT_LOST bit to determine the data format.

Add sample_read_value_size() and next_sample_read_value() helpers to
make it a bit easier to access. Use them in all places where it reads
the struct sample_read_value.

Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
---
tools/perf/tests/sample-parsing.c | 14 +++++---
tools/perf/util/event.h | 18 +++++++++-
tools/perf/util/evsel.c | 33 +++++++++++++-----
.../scripting-engines/trace-event-python.c | 16 ++++++---
tools/perf/util/session.c | 32 +++++++++++------
tools/perf/util/synthetic-events.c | 34 +++++++++++++++----
6 files changed, 112 insertions(+), 35 deletions(-)

diff --git a/tools/perf/tests/sample-parsing.c b/tools/perf/tests/sample-parsing.c
index 07f2411b0ad4..20930dd48ee0 100644
--- a/tools/perf/tests/sample-parsing.c
+++ b/tools/perf/tests/sample-parsing.c
@@ -86,10 +86,15 @@ static bool samples_same(const struct perf_sample *s1,
COMP(read.time_running);
/* PERF_FORMAT_ID is forced for PERF_SAMPLE_READ */
if (read_format & PERF_FORMAT_GROUP) {
- for (i = 0; i < s1->read.group.nr; i++)
- MCOMP(read.group.values[i]);
+ for (i = 0; i < s1->read.group.nr; i++) {
+ /* FIXME: check values without LOST */
+ if (read_format & PERF_FORMAT_LOST)
+ MCOMP(read.group.values[i]);
+ }
} else {
COMP(read.one.id);
+ if (read_format & PERF_FORMAT_LOST)
+ COMP(read.one.lost);
}
}

@@ -263,7 +268,7 @@ static int do_test(u64 sample_type, u64 sample_regs, u64 read_format)
.data = (void *)aux_data,
},
};
- struct sample_read_value values[] = {{1, 5}, {9, 3}, {2, 7}, {6, 4},};
+ struct sample_read_value values[] = {{1, 5, 0}, {9, 3, 0}, {2, 7, 0}, {6, 4, 1},};
struct perf_sample sample_out, sample_out_endian;
size_t i, sz, bufsz;
int err, ret = -1;
@@ -286,6 +291,7 @@ static int do_test(u64 sample_type, u64 sample_regs, u64 read_format)
} else {
sample.read.one.value = 0x08789faeb786aa87ULL;
sample.read.one.id = 99;
+ sample.read.one.lost = 1;
}

sz = perf_event__sample_event_size(&sample, sample_type, read_format);
@@ -370,7 +376,7 @@ static int do_test(u64 sample_type, u64 sample_regs, u64 read_format)
*/
static int test__sample_parsing(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
{
- const u64 rf[] = {4, 5, 6, 7, 12, 13, 14, 15};
+ const u64 rf[] = {4, 5, 6, 7, 12, 13, 14, 15, 20, 21, 22, 28, 29, 30, 31};
u64 sample_type;
u64 sample_regs;
size_t i;
diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index a7b0931d5137..7753368d70d6 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -65,7 +65,8 @@ struct stack_dump {

struct sample_read_value {
u64 value;
- u64 id;
+ u64 id; /* only if PERF_FORMAT_ID */
+ u64 lost; /* only if PERF_FORMAT_LOST */
};

struct sample_read {
@@ -80,6 +81,21 @@ struct sample_read {
};
};

+static inline size_t sample_read_value_size(u64 read_format)
+{
+ /* PERF_FORMAT_ID is forced for PERF_SAMPLE_READ */
+ if (read_format & PERF_FORMAT_LOST)
+ return sizeof(struct sample_read_value);
+ else
+ return offsetof(struct sample_read_value, lost);
+}
+
+static inline struct sample_read_value *
+next_sample_read_value(struct sample_read_value *v, u64 read_format)
+{
+ return (void *)v + sample_read_value_size(read_format);
+}
+
struct ip_callchain {
u64 nr;
u64 ips[];
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 4852089e1d79..781367ccdb84 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1541,7 +1541,7 @@ static int evsel__read_one(struct evsel *evsel, int cpu_map_idx, int thread)
}

static void evsel__set_count(struct evsel *counter, int cpu_map_idx, int thread,
- u64 val, u64 ena, u64 run)
+ u64 val, u64 ena, u64 run, u64 lost)
{
struct perf_counts_values *count;

@@ -1550,6 +1550,7 @@ static void evsel__set_count(struct evsel *counter, int cpu_map_idx, int thread,
count->val = val;
count->ena = ena;
count->run = run;
+ count->lost = lost;

perf_counts__set_loaded(counter->counts, cpu_map_idx, thread, true);
}
@@ -1558,7 +1559,7 @@ static int evsel__process_group_data(struct evsel *leader, int cpu_map_idx, int
{
u64 read_format = leader->core.attr.read_format;
struct sample_read_value *v;
- u64 nr, ena = 0, run = 0, i;
+ u64 nr, ena = 0, run = 0, lost = 0, i;

nr = *data++;

@@ -1573,16 +1574,25 @@ static int evsel__process_group_data(struct evsel *leader, int cpu_map_idx, int

v = (struct sample_read_value *) data;

- evsel__set_count(leader, cpu_map_idx, thread, v[0].value, ena, run);
+ if (read_format & PERF_FORMAT_LOST)
+ lost = v->lost;
+
+ evsel__set_count(leader, cpu_map_idx, thread, v[0].value, ena, run, lost);
+
+ v = next_sample_read_value(v, read_format);

for (i = 1; i < nr; i++) {
struct evsel *counter;

- counter = evlist__id2evsel(leader->evlist, v[i].id);
+ counter = evlist__id2evsel(leader->evlist, v->id);
if (!counter)
return -EINVAL;

- evsel__set_count(counter, cpu_map_idx, thread, v[i].value, ena, run);
+ if (read_format & PERF_FORMAT_LOST)
+ lost = v->lost;
+
+ evsel__set_count(counter, cpu_map_idx, thread, v->value, ena, run, lost);
+ v = next_sample_read_value(v, read_format);
}

return 0;
@@ -2475,16 +2485,21 @@ int evsel__parse_sample(struct evsel *evsel, union perf_event *event,

if (data->read.group.nr > max_group_nr)
return -EFAULT;
- sz = data->read.group.nr *
- sizeof(struct sample_read_value);
+
+ sz = data->read.group.nr * sample_read_value_size(read_format);
OVERFLOW_CHECK(array, sz, max_size);
- data->read.group.values =
- (struct sample_read_value *)array;
+ data->read.group.values = (void *)array;
array = (void *)array + sz;
} else {
OVERFLOW_CHECK_u64(array);
data->read.one.id = *array;
array++;
+
+ if (read_format & PERF_FORMAT_LOST) {
+ OVERFLOW_CHECK_u64(array);
+ data->read.one.lost = *array;
+ array++;
+ }
}
}

diff --git a/tools/perf/util/scripting-engines/trace-event-python.c b/tools/perf/util/scripting-engines/trace-event-python.c
index 9ef2406e0ede..7e15e64f311b 100644
--- a/tools/perf/util/scripting-engines/trace-event-python.c
+++ b/tools/perf/util/scripting-engines/trace-event-python.c
@@ -642,15 +642,19 @@ static PyObject *python_process_brstacksym(struct perf_sample *sample,
return pylist;
}

-static PyObject *get_sample_value_as_tuple(struct sample_read_value *value)
+static PyObject *get_sample_value_as_tuple(struct sample_read_value *value,
+ u64 read_format)
{
PyObject *t;

- t = PyTuple_New(2);
+ t = PyTuple_New(3);
if (!t)
Py_FatalError("couldn't create Python tuple");
PyTuple_SetItem(t, 0, PyLong_FromUnsignedLongLong(value->id));
PyTuple_SetItem(t, 1, PyLong_FromUnsignedLongLong(value->value));
+ if (read_format & PERF_FORMAT_LOST)
+ PyTuple_SetItem(t, 2, PyLong_FromUnsignedLongLong(value->lost));
+
return t;
}

@@ -681,12 +685,16 @@ static void set_sample_read_in_dict(PyObject *dict_sample,
Py_FatalError("couldn't create Python list");

if (read_format & PERF_FORMAT_GROUP) {
+ struct sample_read_value *v = sample->read.group.values;
+
for (i = 0; i < sample->read.group.nr; i++) {
- PyObject *t = get_sample_value_as_tuple(&sample->read.group.values[i]);
+ PyObject *t = get_sample_value_as_tuple(v, read_format);
PyList_SET_ITEM(values, i, t);
+ v = next_sample_read_value(v, read_format);
}
} else {
- PyObject *t = get_sample_value_as_tuple(&sample->read.one);
+ PyObject *t = get_sample_value_as_tuple(&sample->read.one,
+ read_format);
PyList_SET_ITEM(values, 0, t);
}
pydict_set_item_string_decref(dict_sample, "values", values);
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 98e16659a149..dd818764bd4d 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1284,20 +1284,26 @@ static void sample_read__printf(struct perf_sample *sample, u64 read_format)

if (read_format & PERF_FORMAT_GROUP) {
u64 i;
+ struct sample_read_value *value = sample->read.group.values;

printf(".... group nr %" PRIu64 "\n", sample->read.group.nr);

for (i = 0; i < sample->read.group.nr; i++) {
- struct sample_read_value *value;
-
- value = &sample->read.group.values[i];
printf("..... id %016" PRIx64
- ", value %016" PRIx64 "\n",
+ ", value %016" PRIx64,
value->id, value->value);
+ if (read_format & PERF_FORMAT_LOST)
+ printf(", lost %" PRIu64, value->lost);
+ printf("\n");
+ value = next_sample_read_value(value, read_format);
}
- } else
- printf("..... id %016" PRIx64 ", value %016" PRIx64 "\n",
+ } else {
+ printf("..... id %016" PRIx64 ", value %016" PRIx64,
sample->read.one.id, sample->read.one.value);
+ if (read_format & PERF_FORMAT_LOST)
+ printf(", lost %" PRIu64, sample->read.one.lost);
+ printf("\n");
+ }
}

static void dump_event(struct evlist *evlist, union perf_event *event,
@@ -1411,6 +1417,9 @@ static void dump_read(struct evsel *evsel, union perf_event *event)

if (read_format & PERF_FORMAT_ID)
printf("... id : %" PRI_lu64 "\n", read_event->id);
+
+ if (read_format & PERF_FORMAT_LOST)
+ printf("... lost : %" PRI_lu64 "\n", read_event->lost);
}

static struct machine *machines__find_for_cpumode(struct machines *machines,
@@ -1479,17 +1488,20 @@ static int deliver_sample_group(struct evlist *evlist,
struct perf_tool *tool,
union perf_event *event,
struct perf_sample *sample,
- struct machine *machine)
+ struct machine *machine,
+ u64 read_format)
{
int ret = -EINVAL;
u64 i;
+ struct sample_read_value *v = sample->read.group.values;

for (i = 0; i < sample->read.group.nr; i++) {
- ret = deliver_sample_value(evlist, tool, event, sample,
- &sample->read.group.values[i],
+ ret = deliver_sample_value(evlist, tool, event, sample, v,
machine);
if (ret)
break;
+
+ v = next_sample_read_value(v, read_format);
}

return ret;
@@ -1510,7 +1522,7 @@ static int evlist__deliver_sample(struct evlist *evlist, struct perf_tool *tool,
/* For PERF_SAMPLE_READ we have either single or group mode. */
if (read_format & PERF_FORMAT_GROUP)
return deliver_sample_group(evlist, tool, event, sample,
- machine);
+ machine, read_format);
else
return deliver_sample_value(evlist, tool, event, sample,
&sample->read.one, machine);
diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c
index 2ae59c03ae77..9b8dc7633a02 100644
--- a/tools/perf/util/synthetic-events.c
+++ b/tools/perf/util/synthetic-events.c
@@ -1432,11 +1432,12 @@ size_t perf_event__sample_event_size(const struct perf_sample *sample, u64 type,
result += sizeof(u64);
/* PERF_FORMAT_ID is forced for PERF_SAMPLE_READ */
if (read_format & PERF_FORMAT_GROUP) {
- sz = sample->read.group.nr *
- sizeof(struct sample_read_value);
- result += sz;
+ sz = sample_read_value_size(read_format);
+ result += sz * sample->read.group.nr;
} else {
result += sizeof(u64);
+ if (read_format & PERF_FORMAT_LOST)
+ result += sizeof(u64);
}
}

@@ -1521,6 +1522,22 @@ void __weak arch_perf_synthesize_sample_weight(const struct perf_sample *data,
*array = data->weight;
}

+static __u64 *copy_read_group_values(__u64 *array, __u64 read_format,
+ const struct perf_sample *sample)
+{
+ size_t i, sz;
+ void *data = sample->read.group.values;
+
+ sz = sample_read_value_size(read_format);
+ for (i = 0; i < sample->read.group.nr; i++) {
+ memcpy(array, data, sz);
+
+ data += sz;
+ array = (void *)array + sz;
+ }
+ return array;
+}
+
int perf_event__synthesize_sample(union perf_event *event, u64 type, u64 read_format,
const struct perf_sample *sample)
{
@@ -1602,13 +1619,16 @@ int perf_event__synthesize_sample(union perf_event *event, u64 type, u64 read_fo

/* PERF_FORMAT_ID is forced for PERF_SAMPLE_READ */
if (read_format & PERF_FORMAT_GROUP) {
- sz = sample->read.group.nr *
- sizeof(struct sample_read_value);
- memcpy(array, sample->read.group.values, sz);
- array = (void *)array + sz;
+ array = copy_read_group_values(array, read_format,
+ sample);
} else {
*array = sample->read.one.id;
array++;
+
+ if (read_format & PERF_FORMAT_LOST) {
+ *array = sample->read.one.lost;
+ array++;
+ }
}
}

--
2.37.1.595.g718a3a8f04-goog

Next message: Greg Kroah-Hartman: "[PATCH 5.18 0174/1095] hwmon: (dell-smm) Add Dell XPS 13 7390 to fan control whitelist"
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In reply to: Namhyung Kim: "[PATCH 3/4] tools lib perf: Add a test case for read formats"
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