tools/testing/selftests/bpf/prog_tests/test_overhead.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* Copyright (c) 2019 Facebook */
   3 #define _GNU_SOURCE
   4 #include <sched.h>
   5 #include <sys/prctl.h>
   6 #include <test_progs.h>
   7
   8 #define MAX_CNT 100000
   9
  10 static __u64 time_get_ns(void)
  11 {
  12         struct timespec ts;
  13
  14         clock_gettime(CLOCK_MONOTONIC, &ts);
  15         return ts.tv_sec * 1000000000ull + ts.tv_nsec;
  16 }
  17
  18 static int test_task_rename(const char *prog)
  19 {
  20         int i, fd, duration = 0, err;
  21         char buf[] = "test_overhead";
  22         __u64 start_time;
  23
  24         fd = open("/proc/self/comm", O_WRONLY|O_TRUNC);
  25         if (CHECK(fd < 0, "open /proc", "err %d", errno))
  26                 return -1;
  27         start_time = time_get_ns();
  28         for (i = 0; i < MAX_CNT; i++) {
  29                 err = write(fd, buf, sizeof(buf));
  30                 if (err < 0) {
  31                         CHECK(err < 0, "task rename", "err %d", errno);
  32                         close(fd);
  33                         return -1;
  34                 }
  35         }
  36         printf("task_rename %s\t%lluK events per sec\n", prog,
  37                MAX_CNT * 1000000ll / (time_get_ns() - start_time));
  38         close(fd);
  39         return 0;
  40 }
  41
  42 static void test_run(const char *prog)
  43 {
  44         test_task_rename(prog);
  45 }
  46
  47 static void setaffinity(void)
  48 {
  49         cpu_set_t cpuset;
  50         int cpu = 0;
  51
  52         CPU_ZERO(&cpuset);
  53         CPU_SET(cpu, &cpuset);
  54         sched_setaffinity(0, sizeof(cpuset), &cpuset);
  55 }
  56
  57 void test_test_overhead(void)
  58 {
  59         const char *kprobe_name = "kprobe/__set_task_comm";
  60         const char *kretprobe_name = "kretprobe/__set_task_comm";
  61         const char *raw_tp_name = "raw_tp/task_rename";
  62         const char *fentry_name = "fentry/__set_task_comm";
  63         const char *fexit_name = "fexit/__set_task_comm";
  64         const char *kprobe_func = "__set_task_comm";
  65         struct bpf_program *kprobe_prog, *kretprobe_prog, *raw_tp_prog;
  66         struct bpf_program *fentry_prog, *fexit_prog;
  67         struct bpf_object *obj;
  68         struct bpf_link *link;
  69         int err, duration = 0;
  70         char comm[16] = {};
  71
  72         if (CHECK_FAIL(prctl(PR_GET_NAME, comm, 0L, 0L, 0L)))
  73                 return;
  74
  75         obj = bpf_object__open_file("./test_overhead.o", NULL);
  76         if (CHECK(IS_ERR(obj), "obj_open_file", "err %ld\n", PTR_ERR(obj)))
  77                 return;
  78
  79         kprobe_prog = bpf_object__find_program_by_title(obj, kprobe_name);
  80         if (CHECK(!kprobe_prog, "find_probe",
  81                   "prog '%s' not found\n", kprobe_name))
  82                 goto cleanup;
  83         kretprobe_prog = bpf_object__find_program_by_title(obj, kretprobe_name);
  84         if (CHECK(!kretprobe_prog, "find_probe",
  85                   "prog '%s' not found\n", kretprobe_name))
  86                 goto cleanup;
  87         raw_tp_prog = bpf_object__find_program_by_title(obj, raw_tp_name);
  88         if (CHECK(!raw_tp_prog, "find_probe",
  89                   "prog '%s' not found\n", raw_tp_name))
  90                 goto cleanup;
  91         fentry_prog = bpf_object__find_program_by_title(obj, fentry_name);
  92         if (CHECK(!fentry_prog, "find_probe",
  93                   "prog '%s' not found\n", fentry_name))
  94                 goto cleanup;
  95         fexit_prog = bpf_object__find_program_by_title(obj, fexit_name);
  96         if (CHECK(!fexit_prog, "find_probe",
  97                   "prog '%s' not found\n", fexit_name))
  98                 goto cleanup;
  99         err = bpf_object__load(obj);
 100         if (CHECK(err, "obj_load", "err %d\n", err))
 101                 goto cleanup;
 102
 103         setaffinity();
 104
 105         /* base line run */
 106         test_run("base");
 107
 108         /* attach kprobe */
 109         link = bpf_program__attach_kprobe(kprobe_prog, false /* retprobe */,
 110                                           kprobe_func);
 111         if (CHECK(IS_ERR(link), "attach_kprobe", "err %ld\n", PTR_ERR(link)))
 112                 goto cleanup;
 113         test_run("kprobe");
 114         bpf_link__destroy(link);
 115
 116         /* attach kretprobe */
 117         link = bpf_program__attach_kprobe(kretprobe_prog, true /* retprobe */,
 118                                           kprobe_func);
 119         if (CHECK(IS_ERR(link), "attach kretprobe", "err %ld\n", PTR_ERR(link)))
 120                 goto cleanup;
 121         test_run("kretprobe");
 122         bpf_link__destroy(link);
 123
 124         /* attach raw_tp */
 125         link = bpf_program__attach_raw_tracepoint(raw_tp_prog, "task_rename");
 126         if (CHECK(IS_ERR(link), "attach fentry", "err %ld\n", PTR_ERR(link)))
 127                 goto cleanup;
 128         test_run("raw_tp");
 129         bpf_link__destroy(link);
 130
 131         /* attach fentry */
 132         link = bpf_program__attach_trace(fentry_prog);
 133         if (CHECK(IS_ERR(link), "attach fentry", "err %ld\n", PTR_ERR(link)))
 134                 goto cleanup;
 135         test_run("fentry");
 136         bpf_link__destroy(link);
 137
 138         /* attach fexit */
 139         link = bpf_program__attach_trace(fexit_prog);
 140         if (CHECK(IS_ERR(link), "attach fexit", "err %ld\n", PTR_ERR(link)))
 141                 goto cleanup;
 142         test_run("fexit");
 143         bpf_link__destroy(link);
 144
 145 cleanup:
 146         prctl(PR_SET_NAME, comm, 0L, 0L, 0L);
 147         bpf_object__close(obj);
 148 }