A new syntax is appended into parser so user can pass predefined perf
events into BPF objects.
After this patch, BPF programs for perf are finally able to utilize
bpf_perf_event_read() introduced in commit 35578d7984003097af2b1e3
(bpf: Implement function bpf_perf_event_read() that get the selected
hardware PMU conuter) in following way:
===== BPF program bpf_program.c =====
struct bpf_map_def SEC("maps") pmu_map = {
.type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
.key_size = sizeof(int),
.value_size = sizeof(u32),
.max_entries = __NR_CPUS__,
};
SEC("func_write=sys_write")
int func_write(void *ctx)
{
unsigned long long val;
char fmt[] = "sys_write: pmu=%llu\n";
val = bpf_perf_event_read(&pmu_map, bpf_get_smp_processor_id());
bpf_trace_printk(fmt, sizeof(fmt), val);
return 0;
}
SEC("func_write_return=sys_write%return")
int func_write_return(void *ctx)
{
unsigned long long val = 0;
char fmt[] = "sys_write_return: pmu=%llu\n";
val = bpf_perf_event_read(&pmu_map, bpf_get_smp_processor_id());
bpf_trace_printk(fmt, sizeof(fmt), val);
return 0;
}
===== cmdline =====
# echo "" > /sys/kernel/debug/tracing/trace
# perf record -e evt=cycles/period=0x7fffffffffffffff/ \
-e bpf_program.c/maps.pmu_map.event[all]=evt/
-a ls
# cat /sys/kernel/debug/tracing/trace | grep ls
ls-3363 [003] d... 75475.056190: : sys_write: pmu=3961415
ls-3363 [003] dN.. 75475.056212: : sys_write_return: pmu=4051390
ls-3363 [003] d... 75475.056216: : sys_write: pmu=4065447
ls-3363 [003] dN.. 75475.056227: : sys_write_return: pmu=4109760
ls-3363 [003] d... 75475.056230: : sys_write: pmu=4120776
ls-3363 [003] dN.. 75475.056245: : sys_write_return: pmu=4178441
...
# perf report --stdio
Error:
The perf.data file has no samples!
Where, setting period of cycles Set a very large value to period
of cycles event because we want to use this event as a counter
only, don't need sampling.
Signed-off-by: Wang Nan <wangn...@huawei.com>
Signed-off-by: He Kuang <heku...@huawei.com>
Cc: Arnaldo Carvalho de Melo <a...@redhat.com>
Cc: Alexei Starovoitov <a...@plumgrid.com>
Cc: Brendan Gregg <brendan.d.gr...@gmail.com>
Cc: Daniel Borkmann <dan...@iogearbox.net>
Cc: David Ahern <dsah...@gmail.com>
Cc: He Kuang <heku...@huawei.com>
Cc: Jiri Olsa <jo...@kernel.org>
Cc: Kaixu Xia <xiaka...@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu...@hitachi.com>
Cc: Namhyung Kim <namhy...@kernel.org>
Cc: Paul Mackerras <pau...@samba.org>
Cc: Peter Zijlstra <a.p.zijls...@chello.nl>
Cc: Zefan Li <lize...@huawei.com>
Cc: pi3or...@163.com
Link: http://lkml.kernel.org/n/ebpf-2mjd96mowgzslkj8jrwbn...@git.kernel.org
---
tools/perf/util/bpf-loader.c | 106 +++++++++++++++++++++++++++++++++++++++++
tools/perf/util/parse-events.c | 2 +-
2 files changed, 107 insertions(+), 1 deletion(-)
diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index 023fc12..e185fb6 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -643,6 +643,7 @@ enum bpf_map_priv_key_type {
enum bpf_map_priv_value_type {
BPF_MAP_PRIV_VAL_VALUE,
+ BPF_MAP_PRIV_VAL_EVSEL,
};
struct bpf_map_priv {
@@ -660,6 +661,7 @@ struct bpf_map_priv {
enum bpf_map_priv_value_type type;
union {
u64 val;
+ struct perf_evsel *evsel;
};
} value;
};
@@ -715,6 +717,7 @@ bpf_map_config_foreach_key(struct bpf_map *map,
switch (def.type) {
case BPF_MAP_TYPE_ARRAY:
+ case BPF_MAP_TYPE_PERF_EVENT_ARRAY:
switch (priv->key.type) {
case BPF_MAP_PRIV_KEY_ALL:
for (i = 0; i < def.max_entries; i++) {
@@ -838,6 +841,69 @@ bpf__config_obj_map_value(struct bpf_map *map,
return -EINVAL;
}
+static int
+bpf__config_obj_map_array_event(struct bpf_map *map,
+ struct parse_events_term *term,
+ struct perf_evlist *evlist)
+{
+ struct bpf_map_priv *priv;
+ struct perf_evsel *evsel;
+ struct bpf_map_def def;
+ const char *map_name;
+ int err;
+
+ map_name = bpf_map__get_name(map);
+ evsel = perf_evlist__find_evsel_by_alias(evlist, term->val.str);
+ if (!evsel) {
+ pr_debug("Event (for '%s') '%s' doesn't exist\n",
+ map_name, term->val.str);
+ return -EINVAL;
+ }
+
+ err = bpf_map__get_def(map, &def);
+ if (err) {
+ pr_debug("Unable to get map definition from '%s'\n",
+ map_name);
+ return -EINVAL;
+ }
+
+ /*
+ * No need to check key_size and value_size:
+ * kernel has already checked them.
+ */
+ if (def.type != BPF_MAP_TYPE_PERF_EVENT_ARRAY) {
+ pr_debug("Map %s type is not BPF_MAP_TYPE_PERF_EVENT_ARRAY\n",
+ map_name);
+ return -EINVAL;
+ }
+
+ priv = zalloc(sizeof(*priv));
+ if (!priv) {
+ pr_debug("No enough memory for map private\n");
+ return -ENOMEM;
+ }
+
+ err = bpf_map_priv_setkey(priv, term, map_name);
+ if (err)
+ return err;
+
+ priv->value.type = BPF_MAP_PRIV_VAL_EVSEL;
+ priv->value.evsel = evsel;
+ return bpf_map__set_private(map, priv, bpf_map_priv__clear);
+}
+
+static int
+bpf__config_obj_map_event(struct bpf_map *map,
+ struct parse_events_term *term,
+ struct perf_evlist *evlist)
+{
+ if (term->type_val == PARSE_EVENTS__TERM_TYPE_STR)
+ return bpf__config_obj_map_array_event(map, term, evlist);
+
+ pr_debug("ERROR: wrong value type\n");
+ return -EINVAL;
+}
+
struct bpf_config_map_func {
const char *config_opt;
int (*config_func)(struct bpf_map *, struct parse_events_term *,
@@ -846,6 +912,7 @@ struct bpf_config_map_func {
struct bpf_config_map_func bpf_config_map_funcs[] = {
{"value", bpf__config_obj_map_value},
+ {"event", bpf__config_obj_map_event},
};
static int
@@ -964,6 +1031,40 @@ bpf__apply_config_value_for_key(int map_fd, void *pkey,
}
static int
+bpf__apply_config_evsel_for_key(const char *name, int map_fd, void *pkey,
+ struct perf_evsel *evsel)
+{
+ struct xyarray *xy = evsel->fd;
+ unsigned int key, events;
+ int *evt_fd;
+ int err;
+
+ if (!xy) {
+ pr_debug("ERROR: evsel not ready for map %s\n", name);
+ return -EINVAL;
+ }
+
+ if (xy->row_size / xy->entry_size != 1) {
+ pr_debug("ERROR: Dimension of target event is incorrect for map
%s\n",
+ name);
+ return -EINVAL;
+ }
+
+ events = xy->entries / (xy->row_size / xy->entry_size);
+ key = *((unsigned int *)pkey);
+ if (key >= events) {
+ pr_debug("ERROR: there is no event %d for map %s\n",
+ key, name);
+ return -E2BIG;
+ }
+ evt_fd = xyarray__entry(xy, key, 0);
+ err = bpf_map_update_elem(map_fd, pkey, evt_fd, BPF_ANY);
+ if (err && errno)
+ err = -errno;
+ return err;
+}
+
+static int
bpf__apply_config_map_for_key(const char *name, int map_fd,
struct bpf_map_def *pdef __maybe_unused,
struct bpf_map_priv *priv,
@@ -977,6 +1078,10 @@ bpf__apply_config_map_for_key(const char *name, int
map_fd,
pdef->value_size,
priv->value.val);
break;
+ case BPF_MAP_PRIV_VAL_EVSEL:
+ err = bpf__apply_config_evsel_for_key(name, map_fd, pkey,
+ priv->value.evsel);
+ break;
default:
pr_debug("ERROR: unknown value type for '%s'\n", name);
err = -EINVAL;
@@ -1081,6 +1186,7 @@ int bpf__strerror_apply_config(int err, char *buf, size_t
size)
{
bpf__strerror_head(err, buf, size);
bpf__strerror_entry(EINVAL, "Invalid option for map, add -v to see
detail");
+ bpf__strerror_entry(E2BIG, "Array index too big, add -v to see
detail");
bpf__strerror_end(buf, size);
return 0;
}
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index a2af5a8..ae973cd 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -654,7 +654,7 @@ parse_events_config_bpf(struct parse_events_evlist *data,
err, errbuf, sizeof(errbuf));
data->error->help = strdup(
"Hint:\tValid config term:\n"
-" \tmaps.<mapname>.value<indics>\n"
+" \tmaps.<mapname>.[value|event]<indics>\n"
"\n"
" \twhere <indics> is something like [0,3-4]\n"
" \t(add -v to see detail)");
--
1.8.3.4
--
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