LXR linux/tools/testing/selftests/bpf/prog_tests/perf

   1// SPDX-License-Identifier: GPL-2.0
   2#define _GNU_SOURCE
   3#include <pthread.h>
   4#include <sched.h>
   5#include <sys/socket.h>
   6#include <test_progs.h>
   7
   8static void on_sample(void *ctx, int cpu, void *data, __u32 size)
   9{
  10        int cpu_data = *(int *)data, duration = 0;
  11        cpu_set_t *cpu_seen = ctx;
  12
  13        if (cpu_data != cpu)
  14                CHECK(cpu_data != cpu, "check_cpu_data",
  15                      "cpu_data %d != cpu %d\n", cpu_data, cpu);
  16
  17        CPU_SET(cpu, cpu_seen);
  18}
  19
  20void test_perf_buffer(void)
  21{
  22        int err, prog_fd, nr_cpus, i, duration = 0;
  23        const char *prog_name = "kprobe/sys_nanosleep";
  24        const char *file = "./test_perf_buffer.o";
  25        struct perf_buffer_opts pb_opts = {};
  26        struct bpf_map *perf_buf_map;
  27        cpu_set_t cpu_set, cpu_seen;
  28        struct bpf_program *prog;
  29        struct bpf_object *obj;
  30        struct perf_buffer *pb;
  31        struct bpf_link *link;
  32
  33        nr_cpus = libbpf_num_possible_cpus();
  34        if (CHECK(nr_cpus < 0, "nr_cpus", "err %d\n", nr_cpus))
  35                return;
  36
  37        /* load program */
  38        err = bpf_prog_load(file, BPF_PROG_TYPE_KPROBE, &obj, &prog_fd);
  39        if (CHECK(err, "obj_load", "err %d errno %d\n", err, errno))
  40                return;
  41
  42        prog = bpf_object__find_program_by_title(obj, prog_name);
  43        if (CHECK(!prog, "find_probe", "prog '%s' not found\n", prog_name))
  44                goto out_close;
  45
  46        /* load map */
  47        perf_buf_map = bpf_object__find_map_by_name(obj, "perf_buf_map");
  48        if (CHECK(!perf_buf_map, "find_perf_buf_map", "not found\n"))
  49                goto out_close;
  50
  51        /* attach kprobe */
  52        link = bpf_program__attach_kprobe(prog, false /* retprobe */,
  53                                          SYS_NANOSLEEP_KPROBE_NAME);
  54        if (CHECK(IS_ERR(link), "attach_kprobe", "err %ld\n", PTR_ERR(link)))
  55                goto out_close;
  56
  57        /* set up perf buffer */
  58        pb_opts.sample_cb = on_sample;
  59        pb_opts.ctx = &cpu_seen;
  60        pb = perf_buffer__new(bpf_map__fd(perf_buf_map), 1, &pb_opts);
  61        if (CHECK(IS_ERR(pb), "perf_buf__new", "err %ld\n", PTR_ERR(pb)))
  62                goto out_detach;
  63
  64        /* trigger kprobe on every CPU */
  65        CPU_ZERO(&cpu_seen);
  66        for (i = 0; i < nr_cpus; i++) {
  67                CPU_ZERO(&cpu_set);
  68                CPU_SET(i, &cpu_set);
  69
  70                err = pthread_setaffinity_np(pthread_self(), sizeof(cpu_set),
  71                                             &cpu_set);
  72                if (err && CHECK(err, "set_affinity", "cpu #%d, err %d\n",
  73                                 i, err))
  74                        goto out_detach;
  75
  76                usleep(1);
  77        }
  78
  79        /* read perf buffer */
  80        err = perf_buffer__poll(pb, 100);
  81        if (CHECK(err < 0, "perf_buffer__poll", "err %d\n", err))
  82                goto out_free_pb;
  83
  84        if (CHECK(CPU_COUNT(&cpu_seen) != nr_cpus, "seen_cpu_cnt",
  85                  "expect %d, seen %d\n", nr_cpus, CPU_COUNT(&cpu_seen)))
  86                goto out_free_pb;
  87
  88out_free_pb:
  89        perf_buffer__free(pb);
  90out_detach:
  91        bpf_link__destroy(link);
  92out_close:
  93        bpf_object__close(obj);
  94}
  95