linux/samples/bpf/trace_output_user.c
Andrii Nakryiko c17bec549c samples/bpf: switch trace_output sample to perf_buffer API
Convert trace_output sample to libbpf's perf_buffer API.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-07-23 16:05:42 -07:00

89 lines
1.7 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <fcntl.h>
#include <poll.h>
#include <linux/perf_event.h>
#include <linux/bpf.h>
#include <errno.h>
#include <assert.h>
#include <sys/syscall.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <time.h>
#include <signal.h>
#include <libbpf.h>
#include "bpf_load.h"
#include "perf-sys.h"
static __u64 time_get_ns(void)
{
struct timespec ts;
clock_gettime(CLOCK_MONOTONIC, &ts);
return ts.tv_sec * 1000000000ull + ts.tv_nsec;
}
static __u64 start_time;
static __u64 cnt;
#define MAX_CNT 100000ll
static void print_bpf_output(void *ctx, int cpu, void *data, __u32 size)
{
struct {
__u64 pid;
__u64 cookie;
} *e = data;
if (e->cookie != 0x12345678) {
printf("BUG pid %llx cookie %llx sized %d\n",
e->pid, e->cookie, size);
return;
}
cnt++;
if (cnt == MAX_CNT) {
printf("recv %lld events per sec\n",
MAX_CNT * 1000000000ll / (time_get_ns() - start_time));
return;
}
}
int main(int argc, char **argv)
{
struct perf_buffer_opts pb_opts = {};
struct perf_buffer *pb;
char filename[256];
FILE *f;
int ret;
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
if (load_bpf_file(filename)) {
printf("%s", bpf_log_buf);
return 1;
}
pb_opts.sample_cb = print_bpf_output;
pb = perf_buffer__new(map_fd[0], 8, &pb_opts);
ret = libbpf_get_error(pb);
if (ret) {
printf("failed to setup perf_buffer: %d\n", ret);
return 1;
}
f = popen("taskset 1 dd if=/dev/zero of=/dev/null", "r");
(void) f;
start_time = time_get_ns();
while ((ret = perf_buffer__poll(pb, 1000)) >= 0 && cnt < MAX_CNT) {
}
kill(0, SIGINT);
return ret;
}