This patch allows ignoring bpf-output event setting in cmdline.
By adding a map named '__bpf_stdout__', perf automatically creates
an event for it.
For example:
# perf record -e ./test_bpf_trace.c usleep 100000
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.012 MB perf.data (2 samples) ]
# ~/perf script
usleep 4639 [000] 261895.307826: 0
__bpf_stdout__: ffffffff810eb9a1 ...
BPF output: 0000: 52 61 69 73 65 20 61 20 Raise a
0008: 42 50 46 20 65 76 65 6e BPF even
0010: 74 21 00 00 t!..
BPF string: "Raise a BPF event!"
usleep 4639 [000] 261895.407883: 0
__bpf_stdout__: ffffffff8105d609 ...
BPF output: 0000: 52 61 69 73 65 20 61 20 Raise a
0008: 42 50 46 20 65 76 65 6e BPF even
0010: 74 21 00 00 t!..
BPF string: "Raise a BPF event!"
perf record -e ./test_bpf_trace.c usleep 100000
equals to
perf record -e bpf-output/no-inherit=1,name=__bpf_stdout__/ \
-e ./test_bpf_trace.c/map:__bpf_stdout__.event=__bpf_stdout__/ \
usleep 100000
Where test_bpf_trace.c is:
/************************ BEGIN **************************/
#include <uapi/linux/bpf.h>
struct bpf_map_def {
unsigned int type;
unsigned int key_size;
unsigned int value_size;
unsigned int max_entries;
};
#define SEC(NAME) __attribute__((section(NAME), used))
static u64 (*ktime_get_ns)(void) =
(void *)BPF_FUNC_ktime_get_ns;
static int (*trace_printk)(const char *fmt, int fmt_size, ...) =
(void *)BPF_FUNC_trace_printk;
static int (*get_smp_processor_id)(void) =
(void *)BPF_FUNC_get_smp_processor_id;
static int (*perf_event_output)(void *, struct bpf_map_def *, int, void *,
unsigned long) =
(void *)BPF_FUNC_perf_event_output;
struct bpf_map_def SEC("maps") __bpf_stdout__ = {
.type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
.key_size = sizeof(int),
.value_size = sizeof(u32),
.max_entries = __NR_CPUS__,
};
static inline int __attribute__((always_inline))
func(void *ctx, int type)
{
char output_str[] = "Raise a BPF event!";
char err_str[] = "BAD %d\n";
int err;
err = perf_event_output(ctx, &channel, get_smp_processor_id(),
&output_str, sizeof(output_str));
if (err)
trace_printk(err_str, sizeof(err_str), err);
return 1;
}
SEC("func_begin=sys_nanosleep")
int func_begin(void *ctx) {return func(ctx, 1);}
SEC("func_end=sys_nanosleep%return")
int func_end(void *ctx) { return func(ctx, 2);}
char _license[] SEC("license") = "GPL";
int _version SEC("version") = LINUX_VERSION_CODE;
/************************* END ***************************/
Signed-off-by: Wang Nan <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Li Zefan <[email protected]>
Cc: [email protected]
---
tools/perf/util/bpf-loader.c | 37 ++++++++++++++++++++++++++++---------
1 file changed, 28 insertions(+), 9 deletions(-)
diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index a0d2802..1bd7d5b 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -1483,6 +1483,7 @@ int bpf__setup_stdout(struct perf_evlist *evlist
__maybe_unused)
{
struct bpf_map_priv *tmpl_priv = NULL;
struct bpf_object *obj, *tmp;
+ struct perf_evsel *evsel = NULL;
struct bpf_map *map;
int err;
bool need_init = false;
@@ -1507,8 +1508,16 @@ int bpf__setup_stdout(struct perf_evlist *evlist
__maybe_unused)
if (!need_init)
return 0;
- if (!tmpl_priv)
- return 0;
+ if (!tmpl_priv) {
+ err = parse_events(evlist,
"bpf-output/no-inherit=1,name=__bpf_stdout__/",
+ NULL);
+ if (err) {
+ pr_debug("ERROR: failed to create bpf-output event\n");
+ return -err;
+ }
+
+ evsel = perf_evlist__last(evlist);
+ }
bpf__for_each_stdout_map(map, obj, tmp) {
struct bpf_map_priv *priv;
@@ -1519,14 +1528,24 @@ int bpf__setup_stdout(struct perf_evlist *evlist
__maybe_unused)
if (priv)
continue;
- priv = bpf_map_priv__clone(tmpl_priv);
- if (!priv)
- return -ENOMEM;
+ if (tmpl_priv) {
+ priv = bpf_map_priv__clone(tmpl_priv);
+ if (!priv)
+ return -ENOMEM;
- err = bpf_map__set_private(map, priv, bpf_map_priv__clear);
- if (err) {
- bpf_map_priv__clear(map, priv);
- return err;
+ err = bpf_map__set_private(map, priv,
bpf_map_priv__clear);
+ if (err) {
+ bpf_map_priv__clear(map, priv);
+ return err;
+ }
+ } else if (evsel) {
+ struct bpf_map_op *op;
+
+ op = bpf_map__add_newop(map, NULL);
+ if (IS_ERR(op))
+ return PTR_ERR(op);
+ op->op_type = BPF_MAP_OP_SET_EVSEL;
+ op->v.evsel = evsel;
}
}
--
1.8.3.4
