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tools: bpf: move the event reading loop to libbpf

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There are two copies of event reading loop - in bpftool and
trace_helpers "library".  Consolidate them and move the code
to libbpf.  Return codes from trace_helpers are kept, but
renamed to include LIBBPF prefix.

Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Jakub Kicinski
2018-05-10 10:24:40 -07:00
committed by Daniel Borkmann
parent 5f9380572b
commit d0cabbb021
10 changed files with 138 additions and 122 deletions
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87
tools/testing/selftests/bpf/trace_helpers.c
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@@ -74,7 +74,7 @@ struct ksym *ksym_search(long key)
static int page_size;
static int page_cnt = 8;
static volatile struct perf_event_mmap_page *header;
static struct perf_event_mmap_page *header;
int perf_event_mmap(int fd)
{
@@ -107,74 +107,47 @@ struct perf_event_sample {
char data[];
};
static int perf_event_read(perf_event_print_fn fn)
static enum bpf_perf_event_ret bpf_perf_event_print(void *event, void *priv)
{
__u64 data_tail = header->data_tail;
__u64 data_head = header->data_head;
__u64 buffer_size = page_cnt * page_size;
void *base, *begin, *end;
char buf[256];
struct perf_event_sample *e = event;
perf_event_print_fn fn = priv;
int ret;
asm volatile("" ::: "memory"); /* in real code it should be smp_rmb() */
if (data_head == data_tail)
return PERF_EVENT_CONT;
base = ((char *)header) + page_size;
begin = base + data_tail % buffer_size;
end = base + data_head % buffer_size;
while (begin != end) {
struct perf_event_sample *e;
e = begin;
if (begin + e->header.size > base + buffer_size) {
long len = base + buffer_size - begin;
assert(len < e->header.size);
memcpy(buf, begin, len);
memcpy(buf + len, base, e->header.size - len);
e = (void *) buf;
begin = base + e->header.size - len;
} else if (begin + e->header.size == base + buffer_size) {
begin = base;
} else {
begin += e->header.size;
}
if (e->header.type == PERF_RECORD_SAMPLE) {
ret = fn(e->data, e->size);
if (ret != PERF_EVENT_CONT)
return ret;
} else if (e->header.type == PERF_RECORD_LOST) {
struct {
struct perf_event_header header;
__u64 id;
__u64 lost;
} *lost = (void *) e;
printf("lost %lld events\n", lost->lost);
} else {
printf("unknown event type=%d size=%d\n",
e->header.type, e->header.size);
}
if (e->header.type == PERF_RECORD_SAMPLE) {
ret = fn(e->data, e->size);
if (ret != LIBBPF_PERF_EVENT_CONT)
return ret;
} else if (e->header.type == PERF_RECORD_LOST) {
struct {
struct perf_event_header header;
__u64 id;
__u64 lost;
} *lost = (void *) e;
printf("lost %lld events\n", lost->lost);
} else {
printf("unknown event type=%d size=%d\n",
e->header.type, e->header.size);
}
__sync_synchronize(); /* smp_mb() */
header->data_tail = data_head;
return PERF_EVENT_CONT;
return LIBBPF_PERF_EVENT_CONT;
}
int perf_event_poller(int fd, perf_event_print_fn output_fn)
{
int ret;
enum bpf_perf_event_ret ret;
void *buf = NULL;
size_t len = 0;
for (;;) {
perf_event_poll(fd);
ret = perf_event_read(output_fn);
if (ret != PERF_EVENT_CONT)
return ret;
ret = bpf_perf_event_read_simple(header, page_cnt * page_size,
page_size, &buf, &len,
bpf_perf_event_print,
output_fn);
if (ret != LIBBPF_PERF_EVENT_CONT)
break;
}
free(buf);
return PERF_EVENT_DONE;
return ret;
}