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.
Example:
############ BPF program #############
struct bpf_map_def SEC("maps") map_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 = perf_event_output(ctx, &map_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") = 0x40300;
############ cmdline ############
# perf record -g -e evt=bpf-output/no-inherit/ \
-e ./test_bpf_output.c/maps.map_channel.event=evt/ -a ls
# perf data convert --to-ctf ./out.ctf
# babeltrace ./out.ctf
[06:34:00.288671496] (+?.?????????) evt=bpf-output/no-inherit/: { cpu_id = 0
}, { perf_ip = 0xFFFFFFFF811ED5F1, perf_tid = 4469, perf_pid = 4469, perf_id =
3685, raw_len = 3, raw_data = [ [0] = 0xB163D948, [1] = 0x19E6E, [2] = 0x0 ] }
[06:34:00.288677551] (+0.000006055) evt=bpf-output/no-inherit/: { cpu_id = 0
}, { perf_ip = 0xFFFFFFFF811ED5F1, perf_tid = 4469, perf_pid = 4469, perf_id =
3685, raw_len = 3, raw_data = [ [0] = 0xB163F289, [1] = 0x19E6E, [2] = 0x0 ] }
########### python script #######
from babeltrace import TraceCollection
tc = TraceCollection(
tc.add_trace('./out.ctf', 'ctf')
for event in tc.events:
if not event.name.startswith('evt='):
continue
raw_data = event['raw_data']
print(raw_data[0] + raw_data[1] << 32, raw_data[2]));
Signed-off-by: Wang Nan <wangn...@huawei.com>
Cc: Alexei Starovoitov <a...@plumgrid.com>
Cc: Arnaldo Carvalho de Melo <a...@kernel.org>
Cc: Brendan Gregg <brendan.d.gr...@gmail.com>
Cc: Jiri Olsa <jo...@kernel.org>
---
tools/perf/util/data-convert-bt.c | 115 +++++++++++++++++++++++++++++++++++++-
1 file changed, 114 insertions(+), 1 deletion(-)
diff --git a/tools/perf/util/data-convert-bt.c
b/tools/perf/util/data-convert-bt.c
index 34cd1e4..44d6e0d 100644
--- a/tools/perf/util/data-convert-bt.c
+++ b/tools/perf/util/data-convert-bt.c
@@ -352,6 +352,84 @@ static int add_tracepoint_values(struct ctf_writer *cw,
return ret;
}
+static int
+add_bpf_output_values(struct bt_ctf_event_class *event_class,
+ struct bt_ctf_event *event,
+ struct perf_sample *sample)
+{
+ struct bt_ctf_field_type *len_type, *seq_type;
+ struct bt_ctf_field *len_field, *seq_field;
+ unsigned int raw_size = sample->raw_size;
+ unsigned int nr_elements = raw_size / sizeof(u32);
+ unsigned int i;
+ int ret;
+
+ if (nr_elements * sizeof(u32) != raw_size)
+ pr_warning("Incorrect raw_size (%u) in bpf output event, skip
%lu bytes\n",
+ raw_size, nr_elements * sizeof(u32) - raw_size);
+
+ len_type = bt_ctf_event_class_get_field_by_name(event_class, "raw_len");
+ len_field = bt_ctf_field_create(len_type);
+ if (!len_field) {
+ pr_err("failed to create 'raw_len' for bpf output event\n");
+ ret = -1;
+ goto put_len_type;
+ }
+
+ ret = bt_ctf_field_unsigned_integer_set_value(len_field, nr_elements);
+ if (ret) {
+ pr_err("failed to set field value for raw_len\n");
+ goto put_len_field;
+ }
+ ret = bt_ctf_event_set_payload(event, "raw_len", len_field);
+ if (ret) {
+ pr_err("failed to set payload to raw_len\n");
+ goto put_len_field;
+ }
+
+ seq_type = bt_ctf_event_class_get_field_by_name(event_class,
"raw_data");
+ seq_field = bt_ctf_field_create(seq_type);
+ if (!seq_field) {
+ pr_err("failed to create 'raw_data' for bpf output event\n");
+ ret = -1;
+ goto put_seq_type;
+ }
+
+ ret = bt_ctf_field_sequence_set_length(seq_field, len_field);
+ if (ret) {
+ pr_err("failed to set length of 'raw_data'\n");
+ goto put_seq_field;
+ }
+
+ for (i = 0; i < nr_elements; i++) {
+ struct bt_ctf_field *elem_field =
+ bt_ctf_field_sequence_get_field(seq_field, i);
+
+ ret = bt_ctf_field_unsigned_integer_set_value(elem_field,
+ ((u32 *)(sample->raw_data))[i]);
+
+ bt_ctf_field_put(elem_field);
+ if (ret) {
+ pr_err("failed to set raw_data[%d]\n", i);
+ goto put_seq_field;
+ }
+ }
+
+ ret = bt_ctf_event_set_payload(event, "raw_data", seq_field);
+ if (ret)
+ pr_err("failed to set payload for raw_data\n");
+
+put_seq_field:
+ bt_ctf_field_put(seq_field);
+put_seq_type:
+ bt_ctf_field_type_put(seq_type);
+put_len_field:
+ bt_ctf_field_put(len_field);
+put_len_type:
+ bt_ctf_field_type_put(len_type);
+ return ret;
+}
+
static int add_generic_values(struct ctf_writer *cw,
struct bt_ctf_event *event,
struct perf_evsel *evsel,
@@ -597,6 +675,13 @@ static int process_sample_event(struct perf_tool *tool,
return -1;
}
+ if ((evsel->attr.type == PERF_TYPE_SOFTWARE) &&
+ (evsel->attr.config == PERF_COUNT_SW_BPF_OUTPUT)) {
+ ret = add_bpf_output_values(event_class, event, sample);
+ if (ret)
+ return -1;
+ }
+
cs = ctf_stream(cw, get_sample_cpu(cw, sample, evsel));
if (cs) {
if (is_flush_needed(cs))
@@ -744,6 +829,25 @@ static int add_tracepoint_types(struct ctf_writer *cw,
return ret;
}
+static int add_bpf_output_types(struct ctf_writer *cw,
+ struct bt_ctf_event_class *class)
+{
+ struct bt_ctf_field_type *len_type = cw->data.u32;
+ struct bt_ctf_field_type *seq_base_type = cw->data.u32_hex;
+ struct bt_ctf_field_type *seq_type;
+ int ret;
+
+ ret = bt_ctf_event_class_add_field(class, len_type, "raw_len");
+ if (ret)
+ return ret;
+
+ seq_type = bt_ctf_field_type_sequence_create(seq_base_type, "raw_len");
+ if (!seq_type)
+ return -1;
+
+ return bt_ctf_event_class_add_field(class, seq_type, "raw_data");
+}
+
static int add_generic_types(struct ctf_writer *cw, struct perf_evsel *evsel,
struct bt_ctf_event_class *event_class)
{
@@ -755,7 +859,8 @@ static int add_generic_types(struct ctf_writer *cw, struct
perf_evsel *evsel,
* ctf event header
* PERF_SAMPLE_READ - TODO
* PERF_SAMPLE_CALLCHAIN - TODO
- * PERF_SAMPLE_RAW - tracepoint fields are handled separately
+ * PERF_SAMPLE_RAW - tracepoint fields and BPF output
+ * are handled separately
* PERF_SAMPLE_BRANCH_STACK - TODO
* PERF_SAMPLE_REGS_USER - TODO
* PERF_SAMPLE_STACK_USER - TODO
@@ -824,6 +929,14 @@ static int add_event(struct ctf_writer *cw, struct
perf_evsel *evsel)
goto err;
}
+ if ((evsel->attr.type == PERF_TYPE_SOFTWARE) &&
+ (evsel->attr.config == PERF_COUNT_SW_BPF_OUTPUT)) {
+ ret = add_bpf_output_types(cw, event_class);
+ if (ret)
+ goto err;
+
+ }
+
ret = bt_ctf_stream_class_add_event_class(cw->stream_class,
event_class);
if (ret) {
pr("Failed to add event class into stream.\n");
--
1.8.3.4
--
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