Skip to content

Commit d0cabbb

Browse files
Jakub Kicinskiborkmann
Jakub Kicinski
authored and
borkmann
committed
tools: bpf: move the event reading loop to libbpf
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>
1 parent 5f93805 commit d0cabbb

File tree

10 files changed

+139
-123
lines changed

10 files changed

+139
-123
lines changed

‎samples/bpf/Makefile

Lines changed: 8 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -165,6 +165,14 @@ HOSTCFLAGS += -I$(srctree)/tools/lib/ -I$(srctree)/tools/include
165165
HOSTCFLAGS += -I$(srctree)/tools/perf
166166

167167
HOSTCFLAGS_bpf_load.o += -I$(objtree)/usr/include -Wno-unused-variable
168+
HOSTCFLAGS_trace_helpers.o += -I$(srctree)/tools/lib/bpf/
169+
170+
HOSTCFLAGS_trace_output_user.o += -I$(srctree)/tools/lib/bpf/
171+
HOSTCFLAGS_offwaketime_user.o += -I$(srctree)/tools/lib/bpf/
172+
HOSTCFLAGS_spintest_user.o += -I$(srctree)/tools/lib/bpf/
173+
HOSTCFLAGS_trace_event_user.o += -I$(srctree)/tools/lib/bpf/
174+
HOSTCFLAGS_sampleip_user.o += -I$(srctree)/tools/lib/bpf/
175+
168176
HOSTLOADLIBES_test_lru_dist += -lelf
169177
HOSTLOADLIBES_sock_example += -lelf
170178
HOSTLOADLIBES_fds_example += -lelf

‎samples/bpf/trace_output_user.c

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -48,18 +48,18 @@ static int print_bpf_output(void *data, int size)
4848
if (e->cookie != 0x12345678) {
4949
printf("BUG pid %llx cookie %llx sized %d\n",
5050
e->pid, e->cookie, size);
51-
return PERF_EVENT_ERROR;
51+
return LIBBPF_PERF_EVENT_ERROR;
5252
}
5353

5454
cnt++;
5555

5656
if (cnt == MAX_CNT) {
5757
printf("recv %lld events per sec\n",
5858
MAX_CNT * 1000000000ll / (time_get_ns() - start_time));
59-
return PERF_EVENT_DONE;
59+
return LIBBPF_PERF_EVENT_DONE;
6060
}
6161

62-
return PERF_EVENT_CONT;
62+
return LIBBPF_PERF_EVENT_CONT;
6363
}
6464

6565
static void test_bpf_perf_event(void)

‎tools/bpf/bpftool/map_perf_ring.c

Lines changed: 15 additions & 51 deletions
Original file line numberDiff line numberDiff line change
@@ -50,14 +50,15 @@ static void int_exit(int signo)
5050
stop = true;
5151
}
5252

53-
static void
54-
print_bpf_output(struct event_ring_info *ring, struct perf_event_sample *e)
53+
static enum bpf_perf_event_ret print_bpf_output(void *event, void *priv)
5554
{
55+
struct event_ring_info *ring = priv;
56+
struct perf_event_sample *e = event;
5657
struct {
5758
struct perf_event_header header;
5859
__u64 id;
5960
__u64 lost;
60-
} *lost = (void *)e;
61+
} *lost = event;
6162

6263
if (json_output) {
6364
jsonw_start_object(json_wtr);
@@ -96,60 +97,23 @@ print_bpf_output(struct event_ring_info *ring, struct perf_event_sample *e)
9697
e->header.type, e->header.size);
9798
}
9899
}
100+
101+
return LIBBPF_PERF_EVENT_CONT;
99102
}
100103

101104
static void
102105
perf_event_read(struct event_ring_info *ring, void **buf, size_t *buf_len)
103106
{
104-
volatile struct perf_event_mmap_page *header = ring->mem;
105-
__u64 buffer_size = MMAP_PAGE_CNT * get_page_size();
106-
__u64 data_tail = header->data_tail;
107-
__u64 data_head = header->data_head;
108-
void *base, *begin, *end;
109-
110-
asm volatile("" ::: "memory"); /* in real code it should be smp_rmb() */
111-
if (data_head == data_tail)
112-
return;
113-
114-
base = ((char *)header) + get_page_size();
115-
116-
begin = base + data_tail % buffer_size;
117-
end = base + data_head % buffer_size;
118-
119-
while (begin != end) {
120-
struct perf_event_sample *e;
121-
122-
e = begin;
123-
if (begin + e->header.size > base + buffer_size) {
124-
long len = base + buffer_size - begin;
125-
126-
if (*buf_len < e->header.size) {
127-
free(*buf);
128-
*buf = malloc(e->header.size);
129-
if (!*buf) {
130-
fprintf(stderr,
131-
"can't allocate memory");
132-
stop = true;
133-
return;
134-
}
135-
*buf_len = e->header.size;
136-
}
137-
138-
memcpy(*buf, begin, len);
139-
memcpy(*buf + len, base, e->header.size - len);
140-
e = (void *)*buf;
141-
begin = base + e->header.size - len;
142-
} else if (begin + e->header.size == base + buffer_size) {
143-
begin = base;
144-
} else {
145-
begin += e->header.size;
146-
}
147-
148-
print_bpf_output(ring, e);
107+
enum bpf_perf_event_ret ret;
108+
109+
ret = bpf_perf_event_read_simple(ring->mem,
110+
MMAP_PAGE_CNT * get_page_size(),
111+
get_page_size(), buf, buf_len,
112+
print_bpf_output, ring);
113+
if (ret != LIBBPF_PERF_EVENT_CONT) {
114+
fprintf(stderr, "perf read loop failed with %d\n", ret);
115+
stop = true;
149116
}
150-
151-
__sync_synchronize(); /* smp_mb() */
152-
header->data_tail = data_head;
153117
}
154118

155119
static int perf_mmap_size(void)

‎tools/lib/bpf/Makefile

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -69,7 +69,7 @@ FEATURE_USER = .libbpf
6969
FEATURE_TESTS = libelf libelf-getphdrnum libelf-mmap bpf
7070
FEATURE_DISPLAY = libelf bpf
7171

72-
INCLUDES = -I. -I$(srctree)/tools/include -I$(srctree)/tools/arch/$(ARCH)/include/uapi -I$(srctree)/tools/include/uapi
72+
INCLUDES = -I. -I$(srctree)/tools/include -I$(srctree)/tools/arch/$(ARCH)/include/uapi -I$(srctree)/tools/include/uapi -I$(srctree)/tools/perf
7373
FEATURE_CHECK_CFLAGS-bpf = $(INCLUDES)
7474

7575
check_feat := 1

‎tools/lib/bpf/libbpf.c

Lines changed: 61 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -31,6 +31,7 @@
3131
#include <unistd.h>
3232
#include <fcntl.h>
3333
#include <errno.h>
34+
#include <perf-sys.h>
3435
#include <asm/unistd.h>
3536
#include <linux/err.h>
3637
#include <linux/kernel.h>
@@ -2210,3 +2211,63 @@ int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
22102211
*prog_fd = bpf_program__fd(first_prog);
22112212
return 0;
22122213
}
2214+
2215+
enum bpf_perf_event_ret
2216+
bpf_perf_event_read_simple(void *mem, unsigned long size,
2217+
unsigned long page_size, void **buf, size_t *buf_len,
2218+
bpf_perf_event_print_t fn, void *priv)
2219+
{
2220+
volatile struct perf_event_mmap_page *header = mem;
2221+
__u64 data_tail = header->data_tail;
2222+
__u64 data_head = header->data_head;
2223+
void *base, *begin, *end;
2224+
int ret;
2225+
2226+
asm volatile("" ::: "memory"); /* in real code it should be smp_rmb() */
2227+
if (data_head == data_tail)
2228+
return LIBBPF_PERF_EVENT_CONT;
2229+
2230+
base = ((char *)header) + page_size;
2231+
2232+
begin = base + data_tail % size;
2233+
end = base + data_head % size;
2234+
2235+
while (begin != end) {
2236+
struct perf_event_header *ehdr;
2237+
2238+
ehdr = begin;
2239+
if (begin + ehdr->size > base + size) {
2240+
long len = base + size - begin;
2241+
2242+
if (*buf_len < ehdr->size) {
2243+
free(*buf);
2244+
*buf = malloc(ehdr->size);
2245+
if (!*buf) {
2246+
ret = LIBBPF_PERF_EVENT_ERROR;
2247+
break;
2248+
}
2249+
*buf_len = ehdr->size;
2250+
}
2251+
2252+
memcpy(*buf, begin, len);
2253+
memcpy(*buf + len, base, ehdr->size - len);
2254+
ehdr = (void *)*buf;
2255+
begin = base + ehdr->size - len;
2256+
} else if (begin + ehdr->size == base + size) {
2257+
begin = base;
2258+
} else {
2259+
begin += ehdr->size;
2260+
}
2261+
2262+
ret = fn(ehdr, priv);
2263+
if (ret != LIBBPF_PERF_EVENT_CONT)
2264+
break;
2265+
2266+
data_tail += ehdr->size;
2267+
}
2268+
2269+
__sync_synchronize(); /* smp_mb() */
2270+
header->data_tail = data_tail;
2271+
2272+
return ret;
2273+
}

‎tools/lib/bpf/libbpf.h

Lines changed: 13 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -267,4 +267,17 @@ int bpf_prog_load(const char *file, enum bpf_prog_type type,
267267
struct bpf_object **pobj, int *prog_fd);
268268

269269
int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags);
270+
271+
enum bpf_perf_event_ret {
272+
LIBBPF_PERF_EVENT_DONE = 0,
273+
LIBBPF_PERF_EVENT_ERROR = -1,
274+
LIBBPF_PERF_EVENT_CONT = -2,
275+
};
276+
277+
typedef enum bpf_perf_event_ret (*bpf_perf_event_print_t)(void *event,
278+
void *priv);
279+
int bpf_perf_event_read_simple(void *mem, unsigned long size,
280+
unsigned long page_size,
281+
void **buf, size_t *buf_len,
282+
bpf_perf_event_print_t fn, void *priv);
270283
#endif

‎tools/testing/selftests/bpf/Makefile

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -10,7 +10,7 @@ ifneq ($(wildcard $(GENHDR)),)
1010
GENFLAGS := -DHAVE_GENHDR
1111
endif
1212

13-
CFLAGS += -Wall -O2 -I$(APIDIR) -I$(LIBDIR) -I$(GENDIR) $(GENFLAGS) -I../../../include
13+
CFLAGS += -Wall -O2 -I$(APIDIR) -I$(LIBDIR) -I$(BPFDIR) -I$(GENDIR) $(GENFLAGS) -I../../../include
1414
LDLIBS += -lcap -lelf -lrt -lpthread
1515

1616
TEST_CUSTOM_PROGS = $(OUTPUT)/urandom_read

‎tools/testing/selftests/bpf/test_progs.c

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -1337,12 +1337,12 @@ static int get_stack_print_output(void *data, int size)
13371337
good_user_stack = true;
13381338
}
13391339
if (!good_kern_stack || !good_user_stack)
1340-
return PERF_EVENT_ERROR;
1340+
return LIBBPF_PERF_EVENT_ERROR;
13411341

13421342
if (cnt == MAX_CNT_RAWTP)
1343-
return PERF_EVENT_DONE;
1343+
return LIBBPF_PERF_EVENT_DONE;
13441344

1345-
return PERF_EVENT_CONT;
1345+
return LIBBPF_PERF_EVENT_CONT;
13461346
}
13471347

13481348
static void test_get_stack_raw_tp(void)

‎tools/testing/selftests/bpf/trace_helpers.c

Lines changed: 30 additions & 57 deletions
Original file line numberDiff line numberDiff line change
@@ -74,7 +74,7 @@ struct ksym *ksym_search(long key)
7474

7575
static int page_size;
7676
static int page_cnt = 8;
77-
static volatile struct perf_event_mmap_page *header;
77+
static struct perf_event_mmap_page *header;
7878

7979
int perf_event_mmap(int fd)
8080
{
@@ -107,74 +107,47 @@ struct perf_event_sample {
107107
char data[];
108108
};
109109

110-
static int perf_event_read(perf_event_print_fn fn)
110+
static enum bpf_perf_event_ret bpf_perf_event_print(void *event, void *priv)
111111
{
112-
__u64 data_tail = header->data_tail;
113-
__u64 data_head = header->data_head;
114-
__u64 buffer_size = page_cnt * page_size;
115-
void *base, *begin, *end;
116-
char buf[256];
112+
struct perf_event_sample *e = event;
113+
perf_event_print_fn fn = priv;
117114
int ret;
118115

119-
asm volatile("" ::: "memory"); /* in real code it should be smp_rmb() */
120-
if (data_head == data_tail)
121-
return PERF_EVENT_CONT;
122-
123-
base = ((char *)header) + page_size;
124-
125-
begin = base + data_tail % buffer_size;
126-
end = base + data_head % buffer_size;
127-
128-
while (begin != end) {
129-
struct perf_event_sample *e;
130-
131-
e = begin;
132-
if (begin + e->header.size > base + buffer_size) {
133-
long len = base + buffer_size - begin;
134-
135-
assert(len < e->header.size);
136-
memcpy(buf, begin, len);
137-
memcpy(buf + len, base, e->header.size - len);
138-
e = (void *) buf;
139-
begin = base + e->header.size - len;
140-
} else if (begin + e->header.size == base + buffer_size) {
141-
begin = base;
142-
} else {
143-
begin += e->header.size;
144-
}
145-
146-
if (e->header.type == PERF_RECORD_SAMPLE) {
147-
ret = fn(e->data, e->size);
148-
if (ret != PERF_EVENT_CONT)
149-
return ret;
150-
} else if (e->header.type == PERF_RECORD_LOST) {
151-
struct {
152-
struct perf_event_header header;
153-
__u64 id;
154-
__u64 lost;
155-
} *lost = (void *) e;
156-
printf("lost %lld events\n", lost->lost);
157-
} else {
158-
printf("unknown event type=%d size=%d\n",
159-
e->header.type, e->header.size);
160-
}
116+
if (e->header.type == PERF_RECORD_SAMPLE) {
117+
ret = fn(e->data, e->size);
118+
if (ret != LIBBPF_PERF_EVENT_CONT)
119+
return ret;
120+
} else if (e->header.type == PERF_RECORD_LOST) {
121+
struct {
122+
struct perf_event_header header;
123+
__u64 id;
124+
__u64 lost;
125+
} *lost = (void *) e;
126+
printf("lost %lld events\n", lost->lost);
127+
} else {
128+
printf("unknown event type=%d size=%d\n",
129+
e->header.type, e->header.size);
161130
}
162131

163-
__sync_synchronize(); /* smp_mb() */
164-
header->data_tail = data_head;
165-
return PERF_EVENT_CONT;
132+
return LIBBPF_PERF_EVENT_CONT;
166133
}
167134

168135
int perf_event_poller(int fd, perf_event_print_fn output_fn)
169136
{
170-
int ret;
137+
enum bpf_perf_event_ret ret;
138+
void *buf = NULL;
139+
size_t len = 0;
171140

172141
for (;;) {
173142
perf_event_poll(fd);
174-
ret = perf_event_read(output_fn);
175-
if (ret != PERF_EVENT_CONT)
176-
return ret;
143+
ret = bpf_perf_event_read_simple(header, page_cnt * page_size,
144+
page_size, &buf, &len,
145+
bpf_perf_event_print,
146+
output_fn);
147+
if (ret != LIBBPF_PERF_EVENT_CONT)
148+
break;
177149
}
150+
free(buf);
178151

179-
return PERF_EVENT_DONE;
152+
return ret;
180153
}

‎tools/testing/selftests/bpf/trace_helpers.h

Lines changed: 4 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -2,6 +2,8 @@
22
#ifndef __TRACE_HELPER_H
33
#define __TRACE_HELPER_H
44

5+
#include <libbpf.h>
6+
57
struct ksym {
68
long addr;
79
char *name;
@@ -10,14 +12,9 @@ struct ksym {
1012
int load_kallsyms(void);
1113
struct ksym *ksym_search(long key);
1214

13-
typedef int (*perf_event_print_fn)(void *data, int size);
14-
15-
/* return code for perf_event_print_fn */
16-
#define PERF_EVENT_DONE 0
17-
#define PERF_EVENT_ERROR -1
18-
#define PERF_EVENT_CONT -2
15+
typedef enum bpf_perf_event_ret (*perf_event_print_fn)(void *data, int size);
1916

2017
int perf_event_mmap(int fd);
21-
/* return PERF_EVENT_DONE or PERF_EVENT_ERROR */
18+
/* return LIBBPF_PERF_EVENT_DONE or LIBBPF_PERF_EVENT_ERROR */
2219
int perf_event_poller(int fd, perf_event_print_fn output_fn);
2320
#endif

0 commit comments

Comments
 (0)