Commit a43eec304259a6c637f4014a6d4767159b6a3aa3 (bpf: introduce
bpf_perf_event_output() helper) add a helper to enable BPF program
output data to perf ring buffer through a new type of perf event
PERF_COUNT_SW_BPF_OUTPUT. This patch enable perf to create perf
event of that type. Now perf user can use following cmdline to
receive output data from BPF programs:
# ./perf record -a -e evt=bpf-output/no-inherit/ \
-e ./test_bpf_output.c/maps:channel:event=evt/ ls /
# ./perf script
perf 12927 [004] 355971.129276: 0 evt=bpf-output/no-inherit/:
ffffffff811ed5f1 sys_write
perf 12927 [004] 355971.129279: 0 evt=bpf-output/no-inherit/:
ffffffff811ed5f1 sys_write
...
Test result:
# cat ./test_bpf_output.c
/************************ BEGIN **************************/
typedef int u32;
typedef unsigned long long u64;
enum bpf_map_type {
BPF_MAP_TYPE_PERF_EVENT_ARRAY = 4,
};
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 (*bpf_ktime_get_ns)(void) =
(void *)5;
static int (*bpf_trace_printk)(const char *fmt, int fmt_size, ...) =
(void *)6;
static int (*bpf_get_smp_processor_id)(void) =
(void *)8;
static int (*bpf_perf_event_output)(void *, struct bpf_map_def *, int, void *,
unsigned long) =
(void *)23;
struct bpf_map_def SEC("maps") channel = {
.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)
{
struct {
u64 ktime;
int cpuid;
} __attribute__((packed)) output_data;
char error_data[] = "Error: failed to output\n";
output_data.cpuid = bpf_get_smp_processor_id();
output_data.ktime = bpf_ktime_get_ns();
int err = bpf_perf_event_output(ctx, &channel,
bpf_get_smp_processor_id(),
&output_data, sizeof(output_data));
if (err)
bpf_trace_printk(error_data, sizeof(error_data));
return 0;
}
char _license[] SEC("license") = "GPL";
int _version SEC("version") = LINUX_VERSION_CODE;
/************************ END ***************************/
# ./perf record -a -e evt=bpf-output/no-inherit/ \
-e ./test_bpf_output.c/maps:channel:event=evt/ ls /
# ./perf script | grep ls
ls 4085 [000] 2746114.230215: evt=bpf-output/no-inherit/:
ffffffff811ed5f1 sys_write (/lib/modules/4.3.0-rc4+/build/vmlinux)
ls 4085 [000] 2746114.230244: evt=bpf-output/no-inherit/:
ffffffff811ed5f1 sys_write (/lib/modules/4.3.0-rc4+/build/vmlinux)
Signed-off-by: Wang Nan <wangn...@huawei.com>
Cc: Alexei Starovoitov <a...@kernel.org>
Cc: Arnaldo Carvalho de Melo <a...@redhat.com>
Cc: Brendan Gregg <brendan.d.gr...@gmail.com>
Cc: David S. Miller <da...@davemloft.net>
Cc: Masami Hiramatsu <masami.hiramatsu...@hitachi.com>
Cc: Namhyung Kim <namhy...@kernel.org>
Cc: Zefan Li <lize...@huawei.com>
Cc: pi3or...@163.com
---
tools/perf/util/evsel.c | 6 ++++++
tools/perf/util/parse-events.c | 4 ++++
tools/perf/util/parse-events.l | 1 +
3 files changed, 11 insertions(+)
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 32131fc..4dee8e3 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -224,6 +224,12 @@ struct perf_evsel *perf_evsel__new_idx(struct
perf_event_attr *attr, int idx)
if (evsel != NULL)
perf_evsel__init(evsel, attr, idx);
+ if ((evsel->attr.type == PERF_TYPE_SOFTWARE) &&
+ (evsel->attr.config == PERF_COUNT_SW_BPF_OUTPUT)) {
+ evsel->attr.sample_type |= PERF_SAMPLE_RAW;
+ evsel->attr.sample_period = 1;
+ }
+
return evsel;
}
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index a419571..1fddc69 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -124,6 +124,10 @@ struct event_symbol event_symbols_sw[PERF_COUNT_SW_MAX] = {
.symbol = "dummy",
.alias = "",
},
+ [PERF_COUNT_SW_BPF_OUTPUT] = {
+ .symbol = "bpf-output",
+ .alias = "",
+ },
};
#define __PERF_EVENT_FIELD(config, name) \
diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
index 8bb3437..27d567f 100644
--- a/tools/perf/util/parse-events.l
+++ b/tools/perf/util/parse-events.l
@@ -249,6 +249,7 @@ cpu-migrations|migrations { return
sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COU
alignment-faults { return sym(yyscanner,
PERF_TYPE_SOFTWARE, PERF_COUNT_SW_ALIGNMENT_FAULTS); }
emulation-faults { return sym(yyscanner,
PERF_TYPE_SOFTWARE, PERF_COUNT_SW_EMULATION_FAULTS); }
dummy { return sym(yyscanner,
PERF_TYPE_SOFTWARE, PERF_COUNT_SW_DUMMY); }
+bpf-output { return sym(yyscanner,
PERF_TYPE_SOFTWARE, PERF_COUNT_SW_BPF_OUTPUT); }
/*
* We have to handle the kernel PMU event
cycles-ct/cycles-t/mem-loads/mem-stores separately.
--
1.8.3.4
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
