* [PATCH bpf-next 0/2] samples: bpf: refactor perf_event user program with libbpf bpf_link
@ 2020-03-10 5:51 Daniel T. Lee
2020-03-10 5:51 ` [PATCH bpf-next 1/2] samples: bpf: move read_trace_pipe to trace_helpers Daniel T. Lee
2020-03-10 5:51 ` [PATCH bpf-next 2/2] samples: bpf: refactor perf_event user program with libbpf bpf_link Daniel T. Lee
0 siblings, 2 replies; 6+ messages in thread
From: Daniel T. Lee @ 2020-03-10 5:51 UTC (permalink / raw)
To: Daniel Borkmann, Alexei Starovoitov; +Cc: Andrii Nakryiko, netdev, bpf
Currently, some samples are using ioctl for enabling perf_event and
attaching BPF programs to this event. However, the bpf_program__attach
of libbpf(using bpf_link) is much more intuitive than the previous
method using ioctl.
bpf_program__attach_perf_event manages the enable of perf_event and
attach of BPF programs to it, so there's no neeed to do this
directly with ioctl.
In addition, bpf_link provides consistency in the use of API because it
allows disable (detach, destroy) for multiple events to be treated as
one bpf_link__destroy.
To refactor samples with using this libbpf API, the bpf_load in the
samples were removed and migrated to libbbpf. Because read_trace_pipe
is used in bpf_load, multiple samples cannot be migrated to libbpf,
this function was moved to trace_helpers.
Daniel T. Lee (2):
samples: bpf: move read_trace_pipe to trace_helpers
samples: bpf: refactor perf_event user program with libbpf bpf_link
samples/bpf/Makefile | 8 +--
samples/bpf/bpf_load.c | 20 -------
samples/bpf/bpf_load.h | 1 -
samples/bpf/sampleip_user.c | 58 +++++++++++++--------
samples/bpf/trace_event_user.c | 57 +++++++++++++-------
samples/bpf/tracex1_user.c | 1 +
samples/bpf/tracex5_user.c | 1 +
tools/testing/selftests/bpf/trace_helpers.c | 23 ++++++++
tools/testing/selftests/bpf/trace_helpers.h | 1 +
9 files changed, 106 insertions(+), 64 deletions(-)
--
2.25.1
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH bpf-next 1/2] samples: bpf: move read_trace_pipe to trace_helpers
2020-03-10 5:51 [PATCH bpf-next 0/2] samples: bpf: refactor perf_event user program with libbpf bpf_link Daniel T. Lee
@ 2020-03-10 5:51 ` Daniel T. Lee
2020-03-10 21:11 ` John Fastabend
2020-03-10 5:51 ` [PATCH bpf-next 2/2] samples: bpf: refactor perf_event user program with libbpf bpf_link Daniel T. Lee
1 sibling, 1 reply; 6+ messages in thread
From: Daniel T. Lee @ 2020-03-10 5:51 UTC (permalink / raw)
To: Daniel Borkmann, Alexei Starovoitov; +Cc: Andrii Nakryiko, netdev, bpf
To reduce the reliance of trace samples (trace*_user) on bpf_load,
move read_trace_pipe to trace_helpers. By moving this bpf_loader helper
elsewhere, trace functions can be easily migrated to libbbpf.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
---
samples/bpf/Makefile | 4 ++--
samples/bpf/bpf_load.c | 20 ------------------
samples/bpf/bpf_load.h | 1 -
samples/bpf/tracex1_user.c | 1 +
samples/bpf/tracex5_user.c | 1 +
tools/testing/selftests/bpf/trace_helpers.c | 23 +++++++++++++++++++++
tools/testing/selftests/bpf/trace_helpers.h | 1 +
7 files changed, 28 insertions(+), 23 deletions(-)
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 79b0fee6943b..ff0061467dd3 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -64,11 +64,11 @@ fds_example-objs := fds_example.o
sockex1-objs := sockex1_user.o
sockex2-objs := sockex2_user.o
sockex3-objs := bpf_load.o sockex3_user.o
-tracex1-objs := bpf_load.o tracex1_user.o
+tracex1-objs := bpf_load.o tracex1_user.o $(TRACE_HELPERS)
tracex2-objs := bpf_load.o tracex2_user.o
tracex3-objs := bpf_load.o tracex3_user.o
tracex4-objs := bpf_load.o tracex4_user.o
-tracex5-objs := bpf_load.o tracex5_user.o
+tracex5-objs := bpf_load.o tracex5_user.o $(TRACE_HELPERS)
tracex6-objs := bpf_load.o tracex6_user.o
tracex7-objs := bpf_load.o tracex7_user.o
test_probe_write_user-objs := bpf_load.o test_probe_write_user_user.o
diff --git a/samples/bpf/bpf_load.c b/samples/bpf/bpf_load.c
index 4574b1939e49..c5ad528f046e 100644
--- a/samples/bpf/bpf_load.c
+++ b/samples/bpf/bpf_load.c
@@ -665,23 +665,3 @@ int load_bpf_file_fixup_map(const char *path, fixup_map_cb fixup_map)
{
return do_load_bpf_file(path, fixup_map);
}
-
-void read_trace_pipe(void)
-{
- int trace_fd;
-
- trace_fd = open(DEBUGFS "trace_pipe", O_RDONLY, 0);
- if (trace_fd < 0)
- return;
-
- while (1) {
- static char buf[4096];
- ssize_t sz;
-
- sz = read(trace_fd, buf, sizeof(buf) - 1);
- if (sz > 0) {
- buf[sz] = 0;
- puts(buf);
- }
- }
-}
diff --git a/samples/bpf/bpf_load.h b/samples/bpf/bpf_load.h
index 814894a12974..4fcd258c616f 100644
--- a/samples/bpf/bpf_load.h
+++ b/samples/bpf/bpf_load.h
@@ -53,6 +53,5 @@ extern int map_data_count;
int load_bpf_file(char *path);
int load_bpf_file_fixup_map(const char *path, fixup_map_cb fixup_map);
-void read_trace_pipe(void);
int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags);
#endif
diff --git a/samples/bpf/tracex1_user.c b/samples/bpf/tracex1_user.c
index af8c20608ab5..55fddbd08702 100644
--- a/samples/bpf/tracex1_user.c
+++ b/samples/bpf/tracex1_user.c
@@ -4,6 +4,7 @@
#include <unistd.h>
#include <bpf/bpf.h>
#include "bpf_load.h"
+#include "trace_helpers.h"
int main(int ac, char **argv)
{
diff --git a/samples/bpf/tracex5_user.c b/samples/bpf/tracex5_user.c
index c4ab91c89494..c2317b39e0d2 100644
--- a/samples/bpf/tracex5_user.c
+++ b/samples/bpf/tracex5_user.c
@@ -8,6 +8,7 @@
#include <bpf/bpf.h>
#include "bpf_load.h"
#include <sys/resource.h>
+#include "trace_helpers.h"
/* install fake seccomp program to enable seccomp code path inside the kernel,
* so that our kprobe attached to seccomp_phase1() can be triggered
diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c
index 7f989b3e4e22..4d0e913bbb22 100644
--- a/tools/testing/selftests/bpf/trace_helpers.c
+++ b/tools/testing/selftests/bpf/trace_helpers.c
@@ -4,12 +4,15 @@
#include <string.h>
#include <assert.h>
#include <errno.h>
+#include <fcntl.h>
#include <poll.h>
#include <unistd.h>
#include <linux/perf_event.h>
#include <sys/mman.h>
#include "trace_helpers.h"
+#define DEBUGFS "/sys/kernel/debug/tracing/"
+
#define MAX_SYMS 300000
static struct ksym syms[MAX_SYMS];
static int sym_cnt;
@@ -86,3 +89,23 @@ long ksym_get_addr(const char *name)
return 0;
}
+
+void read_trace_pipe(void)
+{
+ int trace_fd;
+
+ trace_fd = open(DEBUGFS "trace_pipe", O_RDONLY, 0);
+ if (trace_fd < 0)
+ return;
+
+ while (1) {
+ static char buf[4096];
+ ssize_t sz;
+
+ sz = read(trace_fd, buf, sizeof(buf) - 1);
+ if (sz > 0) {
+ buf[sz] = 0;
+ puts(buf);
+ }
+ }
+}
diff --git a/tools/testing/selftests/bpf/trace_helpers.h b/tools/testing/selftests/bpf/trace_helpers.h
index 0383c9b8adc1..25ef597dd03f 100644
--- a/tools/testing/selftests/bpf/trace_helpers.h
+++ b/tools/testing/selftests/bpf/trace_helpers.h
@@ -12,5 +12,6 @@ struct ksym {
int load_kallsyms(void);
struct ksym *ksym_search(long key);
long ksym_get_addr(const char *name);
+void read_trace_pipe(void);
#endif
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH bpf-next 2/2] samples: bpf: refactor perf_event user program with libbpf bpf_link
2020-03-10 5:51 [PATCH bpf-next 0/2] samples: bpf: refactor perf_event user program with libbpf bpf_link Daniel T. Lee
2020-03-10 5:51 ` [PATCH bpf-next 1/2] samples: bpf: move read_trace_pipe to trace_helpers Daniel T. Lee
@ 2020-03-10 5:51 ` Daniel T. Lee
2020-03-10 21:33 ` John Fastabend
1 sibling, 1 reply; 6+ messages in thread
From: Daniel T. Lee @ 2020-03-10 5:51 UTC (permalink / raw)
To: Daniel Borkmann, Alexei Starovoitov; +Cc: Andrii Nakryiko, netdev, bpf
The bpf_program__attach of libbpf(using bpf_link) is much more intuitive
than the previous method using ioctl.
bpf_program__attach_perf_event manages the enable of perf_event and
attach of BPF programs to it, so there's no neeed to do this
directly with ioctl.
In addition, bpf_link provides consistency in the use of API because it
allows disable (detach, destroy) for multiple events to be treated as
one bpf_link__destroy.
This commit refactors samples that attach the bpf program to perf_event
by using libbbpf instead of ioctl. Also the bpf_load in the samples were
removed and migrated to use libbbpf API.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
---
samples/bpf/Makefile | 4 +--
samples/bpf/sampleip_user.c | 58 ++++++++++++++++++++++------------
samples/bpf/trace_event_user.c | 57 ++++++++++++++++++++++-----------
3 files changed, 78 insertions(+), 41 deletions(-)
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index ff0061467dd3..424f6fe7ce38 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -88,8 +88,8 @@ xdp2-objs := xdp1_user.o
xdp_router_ipv4-objs := xdp_router_ipv4_user.o
test_current_task_under_cgroup-objs := bpf_load.o $(CGROUP_HELPERS) \
test_current_task_under_cgroup_user.o
-trace_event-objs := bpf_load.o trace_event_user.o $(TRACE_HELPERS)
-sampleip-objs := bpf_load.o sampleip_user.o $(TRACE_HELPERS)
+trace_event-objs := trace_event_user.o $(TRACE_HELPERS)
+sampleip-objs := sampleip_user.o $(TRACE_HELPERS)
tc_l2_redirect-objs := bpf_load.o tc_l2_redirect_user.o
lwt_len_hist-objs := bpf_load.o lwt_len_hist_user.o
xdp_tx_iptunnel-objs := xdp_tx_iptunnel_user.o
diff --git a/samples/bpf/sampleip_user.c b/samples/bpf/sampleip_user.c
index b0f115f938bc..8a94ff558b17 100644
--- a/samples/bpf/sampleip_user.c
+++ b/samples/bpf/sampleip_user.c
@@ -10,13 +10,11 @@
#include <errno.h>
#include <signal.h>
#include <string.h>
-#include <assert.h>
#include <linux/perf_event.h>
#include <linux/ptrace.h>
#include <linux/bpf.h>
-#include <sys/ioctl.h>
+#include <bpf/bpf.h>
#include <bpf/libbpf.h>
-#include "bpf_load.h"
#include "perf-sys.h"
#include "trace_helpers.h"
@@ -25,6 +23,7 @@
#define MAX_IPS 8192
#define PAGE_OFFSET 0xffff880000000000
+static int map_fd;
static int nr_cpus;
static void usage(void)
@@ -34,7 +33,8 @@ static void usage(void)
printf(" duration # sampling duration (seconds), default 5\n");
}
-static int sampling_start(int *pmu_fd, int freq)
+static int sampling_start(int *pmu_fd, int freq, struct bpf_program *prog,
+ struct bpf_link **link)
{
int i;
@@ -53,20 +53,22 @@ static int sampling_start(int *pmu_fd, int freq)
fprintf(stderr, "ERROR: Initializing perf sampling\n");
return 1;
}
- assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF,
- prog_fd[0]) == 0);
- assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE, 0) == 0);
+ link[i] = bpf_program__attach_perf_event(prog, pmu_fd[i]);
+ if (link[i] < 0) {
+ fprintf(stderr, "ERROR: Attach perf event\n");
+ return 1;
+ }
}
return 0;
}
-static void sampling_end(int *pmu_fd)
+static void sampling_end(struct bpf_link **link)
{
int i;
for (i = 0; i < nr_cpus; i++)
- close(pmu_fd[i]);
+ bpf_link__destroy(link[i]);
}
struct ipcount {
@@ -128,14 +130,17 @@ static void print_ip_map(int fd)
static void int_exit(int sig)
{
printf("\n");
- print_ip_map(map_fd[0]);
+ print_ip_map(map_fd);
exit(0);
}
int main(int argc, char **argv)
{
+ int prog_fd, *pmu_fd, opt, freq = DEFAULT_FREQ, secs = DEFAULT_SECS;
+ struct bpf_program *prog;
+ struct bpf_object *obj;
+ struct bpf_link **link;
char filename[256];
- int *pmu_fd, opt, freq = DEFAULT_FREQ, secs = DEFAULT_SECS;
/* process arguments */
while ((opt = getopt(argc, argv, "F:h")) != -1) {
@@ -165,36 +170,47 @@ int main(int argc, char **argv)
/* create perf FDs for each CPU */
nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
pmu_fd = malloc(nr_cpus * sizeof(int));
- if (pmu_fd == NULL) {
- fprintf(stderr, "ERROR: malloc of pmu_fd\n");
+ link = malloc(nr_cpus * sizeof(struct bpf_link *));
+ if (pmu_fd == NULL || link == NULL) {
+ fprintf(stderr, "ERROR: malloc of pmu_fd/link\n");
return 1;
}
/* load BPF program */
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
- if (load_bpf_file(filename)) {
+ if (bpf_prog_load(filename, BPF_PROG_TYPE_PERF_EVENT, &obj, &prog_fd)) {
fprintf(stderr, "ERROR: loading BPF program (errno %d):\n",
errno);
- if (strcmp(bpf_log_buf, "") == 0)
- fprintf(stderr, "Try: ulimit -l unlimited\n");
- else
- fprintf(stderr, "%s", bpf_log_buf);
return 1;
}
+
+ prog = bpf_program__next(NULL, obj);
+ if (!prog) {
+ printf("finding a prog in obj file failed\n");
+ return 1;
+ }
+
+ map_fd = bpf_object__find_map_fd_by_name(obj, "ip_map");
+ if (map_fd < 0) {
+ printf("finding a ip_map map in obj file failed\n");
+ return 1;
+ }
+
signal(SIGINT, int_exit);
signal(SIGTERM, int_exit);
/* do sampling */
printf("Sampling at %d Hertz for %d seconds. Ctrl-C also ends.\n",
freq, secs);
- if (sampling_start(pmu_fd, freq) != 0)
+ if (sampling_start(pmu_fd, freq, prog, link) != 0)
return 1;
sleep(secs);
- sampling_end(pmu_fd);
+ sampling_end(link);
free(pmu_fd);
+ free(link);
/* output sample counts */
- print_ip_map(map_fd[0]);
+ print_ip_map(map_fd);
return 0;
}
diff --git a/samples/bpf/trace_event_user.c b/samples/bpf/trace_event_user.c
index 356171bc392b..fb5c7b91e74c 100644
--- a/samples/bpf/trace_event_user.c
+++ b/samples/bpf/trace_event_user.c
@@ -6,22 +6,21 @@
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
-#include <fcntl.h>
-#include <poll.h>
-#include <sys/ioctl.h>
#include <linux/perf_event.h>
#include <linux/bpf.h>
#include <signal.h>
-#include <assert.h>
#include <errno.h>
#include <sys/resource.h>
+#include <bpf/bpf.h>
#include <bpf/libbpf.h>
-#include "bpf_load.h"
#include "perf-sys.h"
#include "trace_helpers.h"
#define SAMPLE_FREQ 50
+/* counts, stackmap */
+static int map_fd[2];
+struct bpf_program *prog;
static bool sys_read_seen, sys_write_seen;
static void print_ksym(__u64 addr)
@@ -137,6 +136,7 @@ static inline int generate_load(void)
static void test_perf_event_all_cpu(struct perf_event_attr *attr)
{
int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
+ struct bpf_link **link = malloc(nr_cpus * sizeof(struct bpf_link *));
int *pmu_fd = malloc(nr_cpus * sizeof(int));
int i, error = 0;
@@ -151,8 +151,12 @@ static void test_perf_event_all_cpu(struct perf_event_attr *attr)
error = 1;
goto all_cpu_err;
}
- assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
- assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE) == 0);
+ link[i] = bpf_program__attach_perf_event(prog, pmu_fd[i]);
+ if (link[i] < 0) {
+ printf("bpf_program__attach_perf_event failed\n");
+ error = 1;
+ goto all_cpu_err;
+ }
}
if (generate_load() < 0) {
@@ -161,11 +165,11 @@ static void test_perf_event_all_cpu(struct perf_event_attr *attr)
}
print_stacks();
all_cpu_err:
- for (i--; i >= 0; i--) {
- ioctl(pmu_fd[i], PERF_EVENT_IOC_DISABLE);
- close(pmu_fd[i]);
- }
+ for (i--; i >= 0; i--)
+ bpf_link__destroy(link[i]);
+
free(pmu_fd);
+ free(link);
if (error)
int_exit(0);
}
@@ -173,6 +177,7 @@ static void test_perf_event_all_cpu(struct perf_event_attr *attr)
static void test_perf_event_task(struct perf_event_attr *attr)
{
int pmu_fd, error = 0;
+ struct bpf_link *link;
/* per task perf event, enable inherit so the "dd ..." command can be traced properly.
* Enabling inherit will cause bpf_perf_prog_read_time helper failure.
@@ -185,8 +190,12 @@ static void test_perf_event_task(struct perf_event_attr *attr)
printf("sys_perf_event_open failed\n");
int_exit(0);
}
- assert(ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
- assert(ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE) == 0);
+ link = bpf_program__attach_perf_event(prog, pmu_fd);
+ if (link < 0) {
+ printf("bpf_program__attach_perf_event failed\n");
+ close(pmu_fd);
+ int_exit(0);
+ }
if (generate_load() < 0) {
error = 1;
@@ -194,8 +203,7 @@ static void test_perf_event_task(struct perf_event_attr *attr)
}
print_stacks();
err:
- ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE);
- close(pmu_fd);
+ bpf_link__destroy(link);
if (error)
int_exit(0);
}
@@ -282,7 +290,9 @@ static void test_bpf_perf_event(void)
int main(int argc, char **argv)
{
struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
+ struct bpf_object *obj;
char filename[256];
+ int prog_fd;
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
setrlimit(RLIMIT_MEMLOCK, &r);
@@ -295,9 +305,20 @@ int main(int argc, char **argv)
return 1;
}
- if (load_bpf_file(filename)) {
- printf("%s", bpf_log_buf);
- return 2;
+ if (bpf_prog_load(filename, BPF_PROG_TYPE_PERF_EVENT, &obj, &prog_fd))
+ return 1;
+
+ prog = bpf_program__next(NULL, obj);
+ if (!prog) {
+ printf("finding a prog in obj file failed\n");
+ return 1;
+ }
+
+ map_fd[0] = bpf_object__find_map_fd_by_name(obj, "counts");
+ map_fd[1] = bpf_object__find_map_fd_by_name(obj, "stackmap");
+ if (map_fd[0] < 0 || map_fd[1] < 0) {
+ printf("finding a counts/stackmap map in obj file failed\n");
+ return 1;
}
if (fork() == 0) {
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* RE: [PATCH bpf-next 1/2] samples: bpf: move read_trace_pipe to trace_helpers
2020-03-10 5:51 ` [PATCH bpf-next 1/2] samples: bpf: move read_trace_pipe to trace_helpers Daniel T. Lee
@ 2020-03-10 21:11 ` John Fastabend
0 siblings, 0 replies; 6+ messages in thread
From: John Fastabend @ 2020-03-10 21:11 UTC (permalink / raw)
To: Daniel T. Lee, Daniel Borkmann, Alexei Starovoitov
Cc: Andrii Nakryiko, netdev, bpf
Daniel T. Lee wrote:
> To reduce the reliance of trace samples (trace*_user) on bpf_load,
> move read_trace_pipe to trace_helpers. By moving this bpf_loader helper
> elsewhere, trace functions can be easily migrated to libbbpf.
>
> Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
> ---
> samples/bpf/Makefile | 4 ++--
> samples/bpf/bpf_load.c | 20 ------------------
> samples/bpf/bpf_load.h | 1 -
> samples/bpf/tracex1_user.c | 1 +
> samples/bpf/tracex5_user.c | 1 +
> tools/testing/selftests/bpf/trace_helpers.c | 23 +++++++++++++++++++++
> tools/testing/selftests/bpf/trace_helpers.h | 1 +
> 7 files changed, 28 insertions(+), 23 deletions(-)
>
Acked-by: John Fastabend <john.fastabend@gmail.com>
^ permalink raw reply [flat|nested] 6+ messages in thread
* RE: [PATCH bpf-next 2/2] samples: bpf: refactor perf_event user program with libbpf bpf_link
2020-03-10 5:51 ` [PATCH bpf-next 2/2] samples: bpf: refactor perf_event user program with libbpf bpf_link Daniel T. Lee
@ 2020-03-10 21:33 ` John Fastabend
2020-03-10 22:49 ` Daniel T. Lee
0 siblings, 1 reply; 6+ messages in thread
From: John Fastabend @ 2020-03-10 21:33 UTC (permalink / raw)
To: Daniel T. Lee, Daniel Borkmann, Alexei Starovoitov
Cc: Andrii Nakryiko, netdev, bpf
Daniel T. Lee wrote:
> The bpf_program__attach of libbpf(using bpf_link) is much more intuitive
> than the previous method using ioctl.
>
> bpf_program__attach_perf_event manages the enable of perf_event and
> attach of BPF programs to it, so there's no neeed to do this
> directly with ioctl.
>
> In addition, bpf_link provides consistency in the use of API because it
> allows disable (detach, destroy) for multiple events to be treated as
> one bpf_link__destroy.
>
> This commit refactors samples that attach the bpf program to perf_event
> by using libbbpf instead of ioctl. Also the bpf_load in the samples were
> removed and migrated to use libbbpf API.
>
> Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
> ---
[...]
>
> int main(int argc, char **argv)
> {
> + int prog_fd, *pmu_fd, opt, freq = DEFAULT_FREQ, secs = DEFAULT_SECS;
> + struct bpf_program *prog;
> + struct bpf_object *obj;
> + struct bpf_link **link;
> char filename[256];
> - int *pmu_fd, opt, freq = DEFAULT_FREQ, secs = DEFAULT_SECS;
>
> /* process arguments */
> while ((opt = getopt(argc, argv, "F:h")) != -1) {
> @@ -165,36 +170,47 @@ int main(int argc, char **argv)
> /* create perf FDs for each CPU */
> nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
> pmu_fd = malloc(nr_cpus * sizeof(int));
> - if (pmu_fd == NULL) {
> - fprintf(stderr, "ERROR: malloc of pmu_fd\n");
> + link = malloc(nr_cpus * sizeof(struct bpf_link *));
> + if (pmu_fd == NULL || link == NULL) {
> + fprintf(stderr, "ERROR: malloc of pmu_fd/link\n");
> return 1;
> }
>
> /* load BPF program */
> snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
> - if (load_bpf_file(filename)) {
> + if (bpf_prog_load(filename, BPF_PROG_TYPE_PERF_EVENT, &obj, &prog_fd)) {
> fprintf(stderr, "ERROR: loading BPF program (errno %d):\n",
> errno);
> - if (strcmp(bpf_log_buf, "") == 0)
> - fprintf(stderr, "Try: ulimit -l unlimited\n");
> - else
> - fprintf(stderr, "%s", bpf_log_buf);
> return 1;
> }
> +
> + prog = bpf_program__next(NULL, obj);
> + if (!prog) {
> + printf("finding a prog in obj file failed\n");
> + return 1;
> + }
> +
> + map_fd = bpf_object__find_map_fd_by_name(obj, "ip_map");
> + if (map_fd < 0) {
> + printf("finding a ip_map map in obj file failed\n");
> + return 1;
> + }
> +
> signal(SIGINT, int_exit);
> signal(SIGTERM, int_exit);
>
> /* do sampling */
> printf("Sampling at %d Hertz for %d seconds. Ctrl-C also ends.\n",
> freq, secs);
> - if (sampling_start(pmu_fd, freq) != 0)
> + if (sampling_start(pmu_fd, freq, prog, link) != 0)
> return 1;
> sleep(secs);
> - sampling_end(pmu_fd);
> + sampling_end(link);
> free(pmu_fd);
> + free(link);
Not really a problem with this patch but on error we don't free() memory but
then on normal exit there is a free() its a bit inconsistent. How about adding
free on errors as well?
>
> /* output sample counts */
> - print_ip_map(map_fd[0]);
> + print_ip_map(map_fd);
>
> return 0;
> }
[...]
> static void print_ksym(__u64 addr)
> @@ -137,6 +136,7 @@ static inline int generate_load(void)
> static void test_perf_event_all_cpu(struct perf_event_attr *attr)
> {
> int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
> + struct bpf_link **link = malloc(nr_cpus * sizeof(struct bpf_link *));
need to check if its null? Its not going to be very friendly to segfault
later. Or maybe I'm missing the check.
> int *pmu_fd = malloc(nr_cpus * sizeof(int));
> int i, error = 0;
>
> @@ -151,8 +151,12 @@ static void test_perf_event_all_cpu(struct perf_event_attr *attr)
> error = 1;
> goto all_cpu_err;
> }
> - assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
> - assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE) == 0);
> + link[i] = bpf_program__attach_perf_event(prog, pmu_fd[i]);
> + if (link[i] < 0) {
> + printf("bpf_program__attach_perf_event failed\n");
> + error = 1;
> + goto all_cpu_err;
> + }
> }
>
> if (generate_load() < 0) {
> @@ -161,11 +165,11 @@ static void test_perf_event_all_cpu(struct perf_event_attr *attr)
> }
> print_stacks();
> all_cpu_err:
> - for (i--; i >= 0; i--) {
> - ioctl(pmu_fd[i], PERF_EVENT_IOC_DISABLE);
> - close(pmu_fd[i]);
> - }
> + for (i--; i >= 0; i--)
> + bpf_link__destroy(link[i]);
> +
> free(pmu_fd);
> + free(link);
> if (error)
> int_exit(0);
> }
Thanks,
John
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH bpf-next 2/2] samples: bpf: refactor perf_event user program with libbpf bpf_link
2020-03-10 21:33 ` John Fastabend
@ 2020-03-10 22:49 ` Daniel T. Lee
0 siblings, 0 replies; 6+ messages in thread
From: Daniel T. Lee @ 2020-03-10 22:49 UTC (permalink / raw)
To: John Fastabend
Cc: Daniel Borkmann, Alexei Starovoitov, Andrii Nakryiko, netdev, bpf
On Wed, Mar 11, 2020 at 6:34 AM John Fastabend <john.fastabend@gmail.com> wrote:
>
> Daniel T. Lee wrote:
> > The bpf_program__attach of libbpf(using bpf_link) is much more intuitive
> > than the previous method using ioctl.
> >
> > bpf_program__attach_perf_event manages the enable of perf_event and
> > attach of BPF programs to it, so there's no neeed to do this
> > directly with ioctl.
> >
> > In addition, bpf_link provides consistency in the use of API because it
> > allows disable (detach, destroy) for multiple events to be treated as
> > one bpf_link__destroy.
> >
> > This commit refactors samples that attach the bpf program to perf_event
> > by using libbbpf instead of ioctl. Also the bpf_load in the samples were
> > removed and migrated to use libbbpf API.
> >
> > Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
> > ---
>
> [...]
>
> >
> > int main(int argc, char **argv)
> > {
> > + int prog_fd, *pmu_fd, opt, freq = DEFAULT_FREQ, secs = DEFAULT_SECS;
> > + struct bpf_program *prog;
> > + struct bpf_object *obj;
> > + struct bpf_link **link;
> > char filename[256];
> > - int *pmu_fd, opt, freq = DEFAULT_FREQ, secs = DEFAULT_SECS;
> >
> > /* process arguments */
> > while ((opt = getopt(argc, argv, "F:h")) != -1) {
> > @@ -165,36 +170,47 @@ int main(int argc, char **argv)
> > /* create perf FDs for each CPU */
> > nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
> > pmu_fd = malloc(nr_cpus * sizeof(int));
> > - if (pmu_fd == NULL) {
> > - fprintf(stderr, "ERROR: malloc of pmu_fd\n");
> > + link = malloc(nr_cpus * sizeof(struct bpf_link *));
> > + if (pmu_fd == NULL || link == NULL) {
> > + fprintf(stderr, "ERROR: malloc of pmu_fd/link\n");
> > return 1;
> > }
> >
> > /* load BPF program */
> > snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
> > - if (load_bpf_file(filename)) {
> > + if (bpf_prog_load(filename, BPF_PROG_TYPE_PERF_EVENT, &obj, &prog_fd)) {
> > fprintf(stderr, "ERROR: loading BPF program (errno %d):\n",
> > errno);
> > - if (strcmp(bpf_log_buf, "") == 0)
> > - fprintf(stderr, "Try: ulimit -l unlimited\n");
> > - else
> > - fprintf(stderr, "%s", bpf_log_buf);
> > return 1;
> > }
> > +
> > + prog = bpf_program__next(NULL, obj);
> > + if (!prog) {
> > + printf("finding a prog in obj file failed\n");
> > + return 1;
> > + }
> > +
> > + map_fd = bpf_object__find_map_fd_by_name(obj, "ip_map");
> > + if (map_fd < 0) {
> > + printf("finding a ip_map map in obj file failed\n");
> > + return 1;
> > + }
> > +
> > signal(SIGINT, int_exit);
> > signal(SIGTERM, int_exit);
> >
> > /* do sampling */
> > printf("Sampling at %d Hertz for %d seconds. Ctrl-C also ends.\n",
> > freq, secs);
> > - if (sampling_start(pmu_fd, freq) != 0)
> > + if (sampling_start(pmu_fd, freq, prog, link) != 0)
> > return 1;
> > sleep(secs);
> > - sampling_end(pmu_fd);
> > + sampling_end(link);
> > free(pmu_fd);
> > + free(link);
>
> Not really a problem with this patch but on error we don't free() memory but
> then on normal exit there is a free() its a bit inconsistent. How about adding
> free on errors as well?
I think you're right.
I'll add free() on errors to keep it consistent.
Will apply feedback right away!
>
> >
> > /* output sample counts */
> > - print_ip_map(map_fd[0]);
> > + print_ip_map(map_fd);
> >
> > return 0;
> > }
>
> [...]
>
> > static void print_ksym(__u64 addr)
> > @@ -137,6 +136,7 @@ static inline int generate_load(void)
> > static void test_perf_event_all_cpu(struct perf_event_attr *attr)
> > {
> > int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
> > + struct bpf_link **link = malloc(nr_cpus * sizeof(struct bpf_link *));
>
> need to check if its null? Its not going to be very friendly to segfault
> later. Or maybe I'm missing the check.
>
Also, checking whether it is null will be more safe.
I'll apply and send next version patch.
> > int *pmu_fd = malloc(nr_cpus * sizeof(int));
> > int i, error = 0;
> >
> > @@ -151,8 +151,12 @@ static void test_perf_event_all_cpu(struct perf_event_attr *attr)
> > error = 1;
> > goto all_cpu_err;
> > }
> > - assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
> > - assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE) == 0);
> > + link[i] = bpf_program__attach_perf_event(prog, pmu_fd[i]);
> > + if (link[i] < 0) {
> > + printf("bpf_program__attach_perf_event failed\n");
> > + error = 1;
> > + goto all_cpu_err;
> > + }
> > }
> >
> > if (generate_load() < 0) {
> > @@ -161,11 +165,11 @@ static void test_perf_event_all_cpu(struct perf_event_attr *attr)
> > }
> > print_stacks();
> > all_cpu_err:
> > - for (i--; i >= 0; i--) {
> > - ioctl(pmu_fd[i], PERF_EVENT_IOC_DISABLE);
> > - close(pmu_fd[i]);
> > - }
> > + for (i--; i >= 0; i--)
> > + bpf_link__destroy(link[i]);
> > +
> > free(pmu_fd);
> > + free(link);
> > if (error)
> > int_exit(0);
> > }
>
> Thanks,
> John
Thank you for your time and effort for the review.
Best,
Daniel
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2020-03-10 22:49 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-03-10 5:51 [PATCH bpf-next 0/2] samples: bpf: refactor perf_event user program with libbpf bpf_link Daniel T. Lee
2020-03-10 5:51 ` [PATCH bpf-next 1/2] samples: bpf: move read_trace_pipe to trace_helpers Daniel T. Lee
2020-03-10 21:11 ` John Fastabend
2020-03-10 5:51 ` [PATCH bpf-next 2/2] samples: bpf: refactor perf_event user program with libbpf bpf_link Daniel T. Lee
2020-03-10 21:33 ` John Fastabend
2020-03-10 22:49 ` Daniel T. Lee
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).