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Subject[PATCH 6/6] perf cpumap: Add range data encoding
From
Often cpumaps encode a range of all CPUs, add a compact encoding that
doesn't require a bit mask or list of all CPUs.

Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/lib/perf/include/perf/event.h | 14 +++
tools/perf/tests/cpumap.c | 52 ++++++++--
tools/perf/util/cpumap.c | 31 +++++-
tools/perf/util/session.c | 5 +
tools/perf/util/synthetic-events.c | 151 ++++++++++++++--------------
5 files changed, 166 insertions(+), 87 deletions(-)

diff --git a/tools/lib/perf/include/perf/event.h b/tools/lib/perf/include/perf/event.h
index 21170f5afb61..43f990b8c58b 100644
--- a/tools/lib/perf/include/perf/event.h
+++ b/tools/lib/perf/include/perf/event.h
@@ -152,6 +152,7 @@ struct perf_record_header_attr {
enum {
PERF_CPU_MAP__CPUS = 0,
PERF_CPU_MAP__MASK = 1,
+ PERF_CPU_MAP__RANGE_CPUS = 2,
};

/*
@@ -185,6 +186,17 @@ struct perf_record_mask_cpu_map64 {
__u64 mask[];
};

+/*
+ * An encoding of a CPU map for a range starting at start_cpu through to
+ * end_cpu. If any_cpu is 1, an any CPU (-1) value (aka dummy value) is present.
+ */
+struct perf_record_range_cpu_map {
+ __u8 any_cpu;
+ __u8 __pad;
+ __u16 start_cpu;
+ __u16 end_cpu;
+};
+
struct __packed perf_record_cpu_map_data {
__u16 type;
union {
@@ -194,6 +206,8 @@ struct __packed perf_record_cpu_map_data {
struct perf_record_mask_cpu_map32 mask32_data;
/* Used when type == PERF_CPU_MAP__MASK and long_size == 8. */
struct perf_record_mask_cpu_map64 mask64_data;
+ /* Used when type == PERF_CPU_MAP__RANGE_CPUS. */
+ struct perf_record_range_cpu_map range_cpu_data;
};
};

diff --git a/tools/perf/tests/cpumap.c b/tools/perf/tests/cpumap.c
index 7ea150cdc137..7c873c6ae3eb 100644
--- a/tools/perf/tests/cpumap.c
+++ b/tools/perf/tests/cpumap.c
@@ -19,7 +19,6 @@ static int process_event_mask(struct perf_tool *tool __maybe_unused,
struct perf_record_cpu_map *map_event = &event->cpu_map;
struct perf_record_cpu_map_data *data;
struct perf_cpu_map *map;
- int i;
unsigned int long_size;

data = &map_event->data;
@@ -32,16 +31,17 @@ static int process_event_mask(struct perf_tool *tool __maybe_unused,

TEST_ASSERT_VAL("wrong nr", data->mask32_data.nr == 1);

- for (i = 0; i < 20; i++) {
+ TEST_ASSERT_VAL("wrong cpu", perf_record_cpu_map_data__test_bit(0, data));
+ TEST_ASSERT_VAL("wrong cpu", !perf_record_cpu_map_data__test_bit(1, data));
+ for (int i = 2; i <= 20; i++)
TEST_ASSERT_VAL("wrong cpu", perf_record_cpu_map_data__test_bit(i, data));
- }

map = cpu_map__new_data(data);
TEST_ASSERT_VAL("wrong nr", perf_cpu_map__nr(map) == 20);

- for (i = 0; i < 20; i++) {
- TEST_ASSERT_VAL("wrong cpu", perf_cpu_map__cpu(map, i).cpu == i);
- }
+ TEST_ASSERT_VAL("wrong cpu", perf_cpu_map__cpu(map, 0).cpu == 0);
+ for (int i = 2; i <= 20; i++)
+ TEST_ASSERT_VAL("wrong cpu", perf_cpu_map__cpu(map, i - 1).cpu == i);

perf_cpu_map__put(map);
return 0;
@@ -73,25 +73,59 @@ static int process_event_cpus(struct perf_tool *tool __maybe_unused,
return 0;
}

+static int process_event_range_cpus(struct perf_tool *tool __maybe_unused,
+ union perf_event *event,
+ struct perf_sample *sample __maybe_unused,
+ struct machine *machine __maybe_unused)
+{
+ struct perf_record_cpu_map *map_event = &event->cpu_map;
+ struct perf_record_cpu_map_data *data;
+ struct perf_cpu_map *map;
+
+ data = &map_event->data;
+
+ TEST_ASSERT_VAL("wrong type", data->type == PERF_CPU_MAP__RANGE_CPUS);
+
+ TEST_ASSERT_VAL("wrong any_cpu", data->range_cpu_data.any_cpu == 0);
+ TEST_ASSERT_VAL("wrong start_cpu", data->range_cpu_data.start_cpu == 1);
+ TEST_ASSERT_VAL("wrong end_cpu", data->range_cpu_data.end_cpu == 256);
+
+ map = cpu_map__new_data(data);
+ TEST_ASSERT_VAL("wrong nr", perf_cpu_map__nr(map) == 256);
+ TEST_ASSERT_VAL("wrong cpu", perf_cpu_map__cpu(map, 0).cpu == 1);
+ TEST_ASSERT_VAL("wrong cpu", perf_cpu_map__max(map).cpu == 256);
+ TEST_ASSERT_VAL("wrong refcnt", refcount_read(&map->refcnt) == 1);
+ perf_cpu_map__put(map);
+ return 0;
+}
+

static int test__cpu_map_synthesize(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
{
struct perf_cpu_map *cpus;

- /* This one is better stores in mask. */
- cpus = perf_cpu_map__new("0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19");
+ /* This one is better stored in a mask. */
+ cpus = perf_cpu_map__new("0,2-20");

TEST_ASSERT_VAL("failed to synthesize map",
!perf_event__synthesize_cpu_map(NULL, cpus, process_event_mask, NULL));

perf_cpu_map__put(cpus);

- /* This one is better stores in cpu values. */
+ /* This one is better stored in cpu values. */
cpus = perf_cpu_map__new("1,256");

TEST_ASSERT_VAL("failed to synthesize map",
!perf_event__synthesize_cpu_map(NULL, cpus, process_event_cpus, NULL));

+ perf_cpu_map__put(cpus);
+
+ /* This one is better stored as a range. */
+ cpus = perf_cpu_map__new("1-256");
+
+ TEST_ASSERT_VAL("failed to synthesize map",
+ !perf_event__synthesize_cpu_map(NULL, cpus, process_event_range_cpus, NULL));
+
perf_cpu_map__put(cpus);
return 0;
}
diff --git a/tools/perf/util/cpumap.c b/tools/perf/util/cpumap.c
index ae43fb88f444..2389bd3e19b8 100644
--- a/tools/perf/util/cpumap.c
+++ b/tools/perf/util/cpumap.c
@@ -112,12 +112,39 @@ static struct perf_cpu_map *cpu_map__from_mask(const struct perf_record_cpu_map_

}

+static struct perf_cpu_map *cpu_map__from_range(const struct perf_record_cpu_map_data *data)
+{
+ struct perf_cpu_map *map;
+ unsigned int i = 0;
+
+ map = perf_cpu_map__empty_new(data->range_cpu_data.end_cpu -
+ data->range_cpu_data.start_cpu + 1 + data->range_cpu_data.any_cpu);
+ if (!map)
+ return NULL;
+
+ if (data->range_cpu_data.any_cpu)
+ map->map[i++].cpu = -1;
+
+ for (int cpu = data->range_cpu_data.start_cpu; cpu <= data->range_cpu_data.end_cpu;
+ i++, cpu++)
+ map->map[i].cpu = cpu;
+
+ return map;
+}
+
struct perf_cpu_map *cpu_map__new_data(const struct perf_record_cpu_map_data *data)
{
- if (data->type == PERF_CPU_MAP__CPUS)
+ switch (data->type) {
+ case PERF_CPU_MAP__CPUS:
return cpu_map__from_entries(data);
- else
+ case PERF_CPU_MAP__MASK:
return cpu_map__from_mask(data);
+ case PERF_CPU_MAP__RANGE_CPUS:
+ return cpu_map__from_range(data);
+ default:
+ pr_err("cpu_map__new_data unknown type %d\n", data->type);
+ return NULL;
+ }
}

size_t cpu_map__fprintf(struct perf_cpu_map *map, FILE *fp)
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index d52a39ba48e3..0acb9de54b06 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -941,6 +941,11 @@ static void perf_event__cpu_map_swap(union perf_event *event,
default:
pr_err("cpu_map swap: unsupported long size\n");
}
+ break;
+ case PERF_CPU_MAP__RANGE_CPUS:
+ data->range_cpu_data.start_cpu = bswap_16(data->range_cpu_data.start_cpu);
+ data->range_cpu_data.end_cpu = bswap_16(data->range_cpu_data.end_cpu);
+ break;
default:
break;
}
diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c
index ec54ac1ed96f..810ed1dc6e6d 100644
--- a/tools/perf/util/synthetic-events.c
+++ b/tools/perf/util/synthetic-events.c
@@ -1183,93 +1183,97 @@ int perf_event__synthesize_thread_map2(struct perf_tool *tool,
return err;
}

-static void synthesize_cpus(struct perf_record_cpu_map_data *data,
- const struct perf_cpu_map *map)
-{
- int i, map_nr = perf_cpu_map__nr(map);
-
- data->cpus_data.nr = map_nr;
+struct synthesize_cpu_map_data {
+ const struct perf_cpu_map *map;
+ int nr;
+ int min_cpu;
+ int max_cpu;
+ int has_any_cpu;
+ int type;
+ size_t size;
+ struct perf_record_cpu_map_data *data;
+};

- for (i = 0; i < map_nr; i++)
- data->cpus_data.cpu[i] = perf_cpu_map__cpu(map, i).cpu;
+static void synthesize_cpus(struct synthesize_cpu_map_data *data)
+{
+ data->data->type = PERF_CPU_MAP__CPUS;
+ data->data->cpus_data.nr = data->nr;
+ for (int i = 0; i < data->nr; i++)
+ data->data->cpus_data.cpu[i] = perf_cpu_map__cpu(data->map, i).cpu;
}

-static void synthesize_mask(struct perf_record_cpu_map_data *data,
- const struct perf_cpu_map *map, int max)
+static void synthesize_mask(struct synthesize_cpu_map_data *data)
{
int idx;
struct perf_cpu cpu;

/* Due to padding, the 4bytes per entry mask variant is always smaller. */
- data->mask32_data.nr = BITS_TO_U32(max);
- data->mask32_data.long_size = 4;
+ data->data->type = PERF_CPU_MAP__MASK;
+ data->data->mask32_data.nr = BITS_TO_U32(data->max_cpu);
+ data->data->mask32_data.long_size = 4;

- perf_cpu_map__for_each_cpu(cpu, idx, map) {
+ perf_cpu_map__for_each_cpu(cpu, idx, data->map) {
int bit_word = cpu.cpu / 32;
- __u32 bit_mask = 1U << (cpu.cpu & 31);
+ u32 bit_mask = 1U << (cpu.cpu & 31);

- data->mask32_data.mask[bit_word] |= bit_mask;
+ data->data->mask32_data.mask[bit_word] |= bit_mask;
}
}

-static size_t cpus_size(const struct perf_cpu_map *map)
+static void synthesize_range_cpus(struct synthesize_cpu_map_data *data)
{
- return sizeof(struct cpu_map_entries) + perf_cpu_map__nr(map) * sizeof(u16);
+ data->data->type = PERF_CPU_MAP__RANGE_CPUS;
+ data->data->range_cpu_data.any_cpu = data->has_any_cpu;
+ data->data->range_cpu_data.start_cpu = data->min_cpu;
+ data->data->range_cpu_data.end_cpu = data->max_cpu;
}

-static size_t mask_size(const struct perf_cpu_map *map, int *max)
-{
- *max = perf_cpu_map__max(map).cpu;
- return sizeof(struct perf_record_mask_cpu_map32) + BITS_TO_U32(*max) * sizeof(__u32);
-}
-
-static void *cpu_map_data__alloc(const struct perf_cpu_map *map, size_t *size,
- u16 *type, int *max)
+static void *cpu_map_data__alloc(struct synthesize_cpu_map_data *syn_data,
+ size_t header_size)
{
size_t size_cpus, size_mask;
- bool is_dummy = perf_cpu_map__empty(map);

- /*
- * Both array and mask data have variable size based
- * on the number of cpus and their actual values.
- * The size of the 'struct perf_record_cpu_map_data' is:
- *
- * array = size of 'struct cpu_map_entries' +
- * number of cpus * sizeof(u64)
- *
- * mask = size of 'struct perf_record_record_cpu_map' +
- * maximum cpu bit converted to size of longs
- *
- * and finally + the size of 'struct perf_record_cpu_map_data'.
- */
- size_cpus = cpus_size(map);
- size_mask = mask_size(map, max);
+ syn_data->nr = perf_cpu_map__nr(syn_data->map);
+ syn_data->has_any_cpu = (perf_cpu_map__cpu(syn_data->map, 0).cpu == -1) ? 1 : 0;

- if (is_dummy || (size_cpus < size_mask)) {
- *size += size_cpus;
- *type = PERF_CPU_MAP__CPUS;
- } else {
- *size += size_mask;
- *type = PERF_CPU_MAP__MASK;
+ syn_data->min_cpu = perf_cpu_map__cpu(syn_data->map, syn_data->has_any_cpu).cpu;
+ syn_data->max_cpu = perf_cpu_map__max(syn_data->map).cpu;
+ if (syn_data->max_cpu - syn_data->min_cpu + 1 == syn_data->nr - syn_data->has_any_cpu) {
+ /* A consecutive range of CPUs can be encoded using a range. */
+ assert(sizeof(u16) + sizeof(struct perf_record_range_cpu_map) == sizeof(u64));
+ syn_data->type = PERF_CPU_MAP__RANGE_CPUS;
+ syn_data->size = header_size + sizeof(u64);
+ return zalloc(syn_data->size);
}

- *size += sizeof(__u16); /* For perf_record_cpu_map_data.type. */
- *size = PERF_ALIGN(*size, sizeof(u64));
- return zalloc(*size);
+ size_cpus = sizeof(u16) + sizeof(struct cpu_map_entries) + syn_data->nr * sizeof(u16);
+ /* Due to padding, the 4bytes per entry mask variant is always smaller. */
+ size_mask = sizeof(u16) + sizeof(struct perf_record_mask_cpu_map32) +
+ BITS_TO_U32(syn_data->max_cpu) * sizeof(__u32);
+ if (syn_data->has_any_cpu || size_cpus < size_mask) {
+ /* Follow the CPU map encoding. */
+ syn_data->type = PERF_CPU_MAP__CPUS;
+ syn_data->size = header_size + PERF_ALIGN(size_cpus, sizeof(u64));
+ return zalloc(syn_data->size);
+ }
+ /* Encode using a bitmask. */
+ syn_data->type = PERF_CPU_MAP__MASK;
+ syn_data->size = header_size + PERF_ALIGN(size_mask, sizeof(u64));
+ return zalloc(syn_data->size);
}

-static void cpu_map_data__synthesize(struct perf_record_cpu_map_data *data,
- const struct perf_cpu_map *map,
- u16 type, int max)
+static void cpu_map_data__synthesize(struct synthesize_cpu_map_data *data)
{
- data->type = type;
-
- switch (type) {
+ switch (data->type) {
case PERF_CPU_MAP__CPUS:
- synthesize_cpus(data, map);
+ synthesize_cpus(data);
break;
case PERF_CPU_MAP__MASK:
- synthesize_mask(data, map, max);
+ synthesize_mask(data);
+ break;
+ case PERF_CPU_MAP__RANGE_CPUS:
+ synthesize_range_cpus(data);
+ break;
default:
break;
}
@@ -1277,23 +1281,22 @@ static void cpu_map_data__synthesize(struct perf_record_cpu_map_data *data,

static struct perf_record_cpu_map *cpu_map_event__new(const struct perf_cpu_map *map)
{
- size_t size = sizeof(struct perf_event_header);
+ struct synthesize_cpu_map_data syn_data = { .map = map };
struct perf_record_cpu_map *event;
- int max;
- u16 type;

- event = cpu_map_data__alloc(map, &size, &type, &max);
+
+ event = cpu_map_data__alloc(&syn_data, sizeof(struct perf_event_header));
if (!event)
return NULL;

+ syn_data.data = &event->data;
event->header.type = PERF_RECORD_CPU_MAP;
- event->header.size = size;
- event->data.type = type;
-
- cpu_map_data__synthesize(&event->data, map, type, max);
+ event->header.size = syn_data.size;
+ cpu_map_data__synthesize(&syn_data);
return event;
}

+
int perf_event__synthesize_cpu_map(struct perf_tool *tool,
const struct perf_cpu_map *map,
perf_event__handler_t process,
@@ -1891,24 +1894,20 @@ int perf_event__synthesize_event_update_name(struct perf_tool *tool, struct evse
int perf_event__synthesize_event_update_cpus(struct perf_tool *tool, struct evsel *evsel,
perf_event__handler_t process)
{
- size_t size = sizeof(struct perf_event_header) + sizeof(u64) + sizeof(u64);
+ struct synthesize_cpu_map_data syn_data = { .map = evsel->core.own_cpus };
struct perf_record_event_update *ev;
- int max, err;
- u16 type;
-
- if (!evsel->core.own_cpus)
- return 0;
+ int err;

- ev = cpu_map_data__alloc(evsel->core.own_cpus, &size, &type, &max);
+ ev = cpu_map_data__alloc(&syn_data, sizeof(struct perf_event_header));
if (!ev)
return -ENOMEM;

+ syn_data.data = &ev->cpus.cpus;
ev->header.type = PERF_RECORD_EVENT_UPDATE;
- ev->header.size = (u16)size;
+ ev->header.size = (u16)syn_data.size;
ev->type = PERF_EVENT_UPDATE__CPUS;
ev->id = evsel->core.id[0];
-
- cpu_map_data__synthesize(&ev->cpus.cpus, evsel->core.own_cpus, type, max);
+ cpu_map_data__synthesize(&syn_data);

err = process(tool, (union perf_event *)ev, NULL, NULL);
free(ev);
--
2.36.1.476.g0c4daa206d-goog
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