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Message-ID: <tip-72c0809856b9174e71eab4e293089f6a114e0d41@git.kernel.org>
Date: Wed, 13 Apr 2016 00:22:50 -0700
From: tip-bot for Wang Nan <tipbot@...or.com>
To: linux-tip-commits@...r.kernel.org
Cc: lizefan@...wei.com, tglx@...utronix.de,
linux-kernel@...r.kernel.org, acme@...hat.com, wangnan0@...wei.com,
mingo@...nel.org, hpa@...or.com, jolsa@...nel.org
Subject: [tip:perf/core] perf bpf: Automatically create bpf-output event
__bpf_stdout__
Commit-ID: 72c0809856b9174e71eab4e293089f6a114e0d41
Gitweb: http://git.kernel.org/tip/72c0809856b9174e71eab4e293089f6a114e0d41
Author: Wang Nan <wangnan0@...wei.com>
AuthorDate: Fri, 8 Apr 2016 15:07:25 +0000
Committer: Arnaldo Carvalho de Melo <acme@...hat.com>
CommitDate: Mon, 11 Apr 2016 22:18:04 -0300
perf bpf: Automatically create bpf-output event __bpf_stdout__
This patch removes the need to set a bpf-output event in cmdline. By
referencing 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, &__bpf_stdout__, 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 ***************************/
Committer note:
Testing with 'perf trace':
# trace -e nanosleep --ev test_bpf_stdout.c usleep 1
0.007 ( 0.007 ms): usleep/729 nanosleep(rqtp: 0x7ffc5bbc5fe0) ...
0.007 ( ): __bpf_stdout__:Raise a BPF event!..)
0.008 ( ): perf_bpf_probe:func_begin:(ffffffff81112460))
0.069 ( ): __bpf_stdout__:Raise a BPF event!..)
0.070 ( ): perf_bpf_probe:func_end:(ffffffff81112460 <- ffffffff81003d92))
0.072 ( 0.072 ms): usleep/729 ... [continued]: nanosleep()) = 0
#
Suggested-and-Tested-by: Arnaldo Carvalho de Melo <acme@...hat.com>
Signed-off-by: Wang Nan <wangnan0@...wei.com>
Cc: Jiri Olsa <jolsa@...nel.org>
Cc: Zefan Li <lizefan@...wei.com>
Cc: pi3orama@....com
Link: http://lkml.kernel.org/r/1460128045-97310-5-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
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 67f61a9..493307d 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;
}
}
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