perf data: Support converting data from bpf_perf_event_output()
bpf_perf_event_output() outputs data through sample->raw_data. This
patch adds support to convert those data into CTF. A python script
then can be used to process output data from BPF programs.
Test result:
# cat ./test_bpf_output_2.c
/************************ 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") channel = {
.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)
{
struct {
u64 ktime;
int type;
} __attribute__((packed)) output_data;
char error_data[] = "Error: failed to output\n";
int err;
output_data.type = type;
output_data.ktime = ktime_get_ns();
err = perf_event_output(ctx, &channel, get_smp_processor_id(),
&output_data, sizeof(output_data));
if (err)
trace_printk(error_data, sizeof(error_data));
return 0;
}
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 ***************************/
# ./perf record -e evt=bpf-output/no-inherit/ \
-e ./test_bpf_output_2.c/maps:channel.event=evt/ \
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 14942 92503.198504: evt=bpf-output/no-inherit/: ffffffff810e0ba1 sys_nanosleep (/lib/modules/4.3.0....
usleep 14942 92503.298562: evt=bpf-output/no-inherit/: ffffffff810585e9 kretprobe_trampoline_holder (/lib....
# ./perf data convert --to-ctf ./out.ctf
[ perf data convert: Converted 'perf.data' into CTF data './out.ctf' ]
[ perf data convert: Converted and wrote 0.000 MB (2 samples) ]
# babeltrace ./out.ctf
[01:41:43.198504134] (+?.?????????) evt=bpf-output/no-inherit/: { cpu_id = 0 }, { perf_ip = 0xFFFFFFFF810E0BA1, perf_tid = 14942, perf_pid = 14942, perf_id = 1044, raw_len = 3, raw_data = [ [0] = 0x32C0C07B, [1] = 0x5421, [2] = 0x1 ] }
[01:41:43.298562257] (+0.100058123) evt=bpf-output/no-inherit/: { cpu_id = 0 }, { perf_ip = 0xFFFFFFFF810585E9, perf_tid = 14942, perf_pid = 14942, perf_id = 1044, raw_len = 3, raw_data = [ [0] = 0x38B77FAA, [1] = 0x5421, [2] = 0x2 ] }
# cat ./test_bpf_output_2.py
from babeltrace import TraceCollection
tc = TraceCollection(
tc.add_trace('./out.ctf', 'ctf')
d = {1:[], 2:[]}
for event in tc.events:
if not event.name.startswith('evt=bpf-output/no-inherit/'):
continue
raw_data = event['raw_data']
(time, type) = ((raw_data[0] + (raw_data[1] << 32)), raw_data[2])
d[type].append(time)
print(list(map(lambda i: d[2][i] - d[1][i], range(len(d[1]))))));
# python3 ./test_bpf_output_2.py
[100056879]
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
1 file changed