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#include "bpf/libbpf_internal.h"
   8
   9static void on_sample(void *ctx, int cpu, void *data, __u32 size)
  10{
  11        int cpu_data = *(int *)data, duration = 0;
  12        cpu_set_t *cpu_seen = ctx;
  13
  14        if (cpu_data != cpu)
  15                CHECK(cpu_data != cpu, "check_cpu_data",
  16                      "cpu_data %d != cpu %d\n", cpu_data, cpu);
  17
  18        CPU_SET(cpu, cpu_seen);
  19}
  20
  21void test_perf_buffer(void)
  22{
  23        int err, prog_fd, on_len, nr_on_cpus = 0,  nr_cpus, i, duration = 0;
  24        const char *prog_name = "kprobe/sys_nanosleep";
  25        const char *file = "./test_perf_buffer.o";
  26        struct perf_buffer_opts pb_opts = {};
  27        struct bpf_map *perf_buf_map;
  28        cpu_set_t cpu_set, cpu_seen;
  29        struct bpf_program *prog;
  30        struct bpf_object *obj;
  31        struct perf_buffer *pb;
  32        struct bpf_link *link;
  33        bool *online;
  34
  35        nr_cpus = libbpf_num_possible_cpus();
  36        if (CHECK(nr_cpus < 0, "nr_cpus", "err %d\n", nr_cpus))
  37                return;
  38
  39        err = parse_cpu_mask_file("/sys/devices/system/cpu/online",
  40                                  &online, &on_len);
  41        if (CHECK(err, "nr_on_cpus", "err %d\n", err))
  42                return;
  43
  44        for (i = 0; i < on_len; i++)
  45                if (online[i])
  46                        nr_on_cpus++;
  47
  48        /* load program */
  49        err = bpf_prog_load(file, BPF_PROG_TYPE_KPROBE, &obj, &prog_fd);
  50        if (CHECK(err, "obj_load", "err %d errno %d\n", err, errno)) {
  51                obj = NULL;
  52                goto out_close;
  53        }
  54
  55        prog = bpf_object__find_program_by_title(obj, prog_name);
  56        if (CHECK(!prog, "find_probe", "prog '%s' not found\n", prog_name))
  57                goto out_close;
  58
  59        /* load map */
  60        perf_buf_map = bpf_object__find_map_by_name(obj, "perf_buf_map");
  61        if (CHECK(!perf_buf_map, "find_perf_buf_map", "not found\n"))
  62                goto out_close;
  63
  64        /* attach kprobe */
  65        link = bpf_program__attach_kprobe(prog, false /* retprobe */,
  66                                          SYS_NANOSLEEP_KPROBE_NAME);
  67        if (CHECK(IS_ERR(link), "attach_kprobe", "err %ld\n", PTR_ERR(link)))
  68                goto out_close;
  69
  70        /* set up perf buffer */
  71        pb_opts.sample_cb = on_sample;
  72        pb_opts.ctx = &cpu_seen;
  73        pb = perf_buffer__new(bpf_map__fd(perf_buf_map), 1, &pb_opts);
  74        if (CHECK(IS_ERR(pb), "perf_buf__new", "err %ld\n", PTR_ERR(pb)))
  75                goto out_detach;
  76
  77        /* trigger kprobe on every CPU */
  78        CPU_ZERO(&cpu_seen);
  79        for (i = 0; i < nr_cpus; i++) {
  80                if (i >= on_len || !online[i]) {
  81                        printf("skipping offline CPU #%d\n", i);
  82                        continue;
  83                }
  84
  85                CPU_ZERO(&cpu_set);
  86                CPU_SET(i, &cpu_set);
  87
  88                err = pthread_setaffinity_np(pthread_self(), sizeof(cpu_set),
  89                                             &cpu_set);
  90                if (err && CHECK(err, "set_affinity", "cpu #%d, err %d\n",
  91                                 i, err))
  92                        goto out_detach;
  93
  94                usleep(1);
  95        }
  96
  97        /* read perf buffer */
  98        err = perf_buffer__poll(pb, 100);
  99        if (CHECK(err < 0, "perf_buffer__poll", "err %d\n", err))
 100                goto out_free_pb;
 101
 102        if (CHECK(CPU_COUNT(&cpu_seen) != nr_on_cpus, "seen_cpu_cnt",
 103                  "expect %d, seen %d\n", nr_on_cpus, CPU_COUNT(&cpu_seen)))
 104                goto out_free_pb;
 105
 106out_free_pb:
 107        perf_buffer__free(pb);
 108out_detach:
 109        bpf_link__destroy(link);
 110out_close:
 111        bpf_object__close(obj);
 112        free(online);
 113}
 114