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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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tools/bpf/bpftool/map_perf_ring.c
+14 -50
View File
@@ -50,14 +50,15 @@ static void int_exit(int signo)
stop = true;
}
static void
print_bpf_output(struct event_ring_info *ring, struct perf_event_sample *e)
static enum bpf_perf_event_ret print_bpf_output(void *event, void *priv)
{
struct event_ring_info *ring = priv;
struct perf_event_sample *e = event;
struct {
struct perf_event_header header;
__u64 id;
__u64 lost;
} *lost = (void *)e;
} *lost = event;
if (json_output) {
jsonw_start_object(json_wtr);
@@ -96,60 +97,23 @@ print_bpf_output(struct event_ring_info *ring, struct perf_event_sample *e)
e->header.type, e->header.size);
}
}
return LIBBPF_PERF_EVENT_CONT;
}
static void
perf_event_read(struct event_ring_info *ring, void **buf, size_t *buf_len)
{
volatile struct perf_event_mmap_page *header = ring->mem;
__u64 buffer_size = MMAP_PAGE_CNT * get_page_size();
__u64 data_tail = header->data_tail;
__u64 data_head = header->data_head;
void *base, *begin, *end;
enum bpf_perf_event_ret ret;
asm volatile("" ::: "memory"); /* in real code it should be smp_rmb() */
if (data_head == data_tail)
return;
base = ((char *)header) + get_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;
if (*buf_len < e->header.size) {
free(*buf);
*buf = malloc(e->header.size);
if (!*buf) {
fprintf(stderr,
"can't allocate memory");
stop = true;
return;
}
*buf_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;
}
print_bpf_output(ring, e);
ret = bpf_perf_event_read_simple(ring->mem,
MMAP_PAGE_CNT * get_page_size(),
get_page_size(), buf, buf_len,
print_bpf_output, ring);
if (ret != LIBBPF_PERF_EVENT_CONT) {
fprintf(stderr, "perf read loop failed with %d\n", ret);
stop = true;
}
__sync_synchronize(); /* smp_mb() */
header->data_tail = data_head;
}
static int perf_mmap_size(void)