Quelle  test_overhead.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2019 Facebook */
#define _GNU_SOURCE
#include <sched.h>
#include <sys/prctl.h>
#include <test_progs.h>

#define MAX_CNT 100000

static __u64 time_get_ns(void)
{
 struct timespec ts;

 clock_gettime(CLOCK_MONOTONIC, &ts);
 return ts.tv_sec * 1000000000ull + ts.tv_nsec;
}

static int test_task_rename(const char *prog)
{
 int i, fd, duration = 0, err;
 char buf[] = "test_overhead";
 __u64 start_time;

 fd = open("/proc/self/comm", O_WRONLY|O_TRUNC);
 if (CHECK(fd < 0, "open /proc", "err %d", errno))
  return -1;
 start_time = time_get_ns();
 for (i = 0; i < MAX_CNT; i++) {
  err = write(fd, buf, sizeof(buf));
  if (err < 0) {
   CHECK(err < 0, "task rename", "err %d", errno);
   close(fd);
   return -1;
  }
 }
 printf("task_rename %s\t%lluK events per sec\n", prog,
        MAX_CNT * 1000000ll / (time_get_ns() - start_time));
 close(fd);
 return 0;
}

static void test_run(const char *prog)
{
 test_task_rename(prog);
}

static void setaffinity(void)
{
 cpu_set_t cpuset;
 int cpu = 0;

 CPU_ZERO(&cpuset);
 CPU_SET(cpu, &cpuset);
 sched_setaffinity(0, sizeof(cpuset), &cpuset);
}

void test_test_overhead(void)
{
 const char *kprobe_name = "prog1";
 const char *kretprobe_name = "prog2";
 const char *raw_tp_name = "prog3";
 const char *fentry_name = "prog4";
 const char *fexit_name = "prog5";
 const char *kprobe_func = "__set_task_comm";
 struct bpf_program *kprobe_prog, *kretprobe_prog, *raw_tp_prog;
 struct bpf_program *fentry_prog, *fexit_prog;
 struct bpf_object *obj;
 struct bpf_link *link;
 int err, duration = 0;
 char comm[16] = {};

 if (CHECK_FAIL(prctl(PR_GET_NAME, comm, 0L, 0L, 0L)))
  return;

 obj = bpf_object__open_file("./test_overhead.bpf.o", NULL);
 if (!ASSERT_OK_PTR(obj, "obj_open_file"))
  return;

 kprobe_prog = bpf_object__find_program_by_name(obj, kprobe_name);
 if (CHECK(!kprobe_prog, "find_probe",
    "prog '%s' not found\n", kprobe_name))
  goto cleanup;
 kretprobe_prog = bpf_object__find_program_by_name(obj, kretprobe_name);
 if (CHECK(!kretprobe_prog, "find_probe",
    "prog '%s' not found\n", kretprobe_name))
  goto cleanup;
 raw_tp_prog = bpf_object__find_program_by_name(obj, raw_tp_name);
 if (CHECK(!raw_tp_prog, "find_probe",
    "prog '%s' not found\n", raw_tp_name))
  goto cleanup;
 fentry_prog = bpf_object__find_program_by_name(obj, fentry_name);
 if (CHECK(!fentry_prog, "find_probe",
    "prog '%s' not found\n", fentry_name))
  goto cleanup;
 fexit_prog = bpf_object__find_program_by_name(obj, fexit_name);
 if (CHECK(!fexit_prog, "find_probe",
    "prog '%s' not found\n", fexit_name))
  goto cleanup;
 err = bpf_object__load(obj);
 if (CHECK(err, "obj_load", "err %d\n", err))
  goto cleanup;

 setaffinity();

 /* base line run */
 test_run("base");

 /* attach kprobe */
 link = bpf_program__attach_kprobe(kprobe_prog, false /* retprobe */,
       kprobe_func);
 if (!ASSERT_OK_PTR(link, "attach_kprobe"))
  goto cleanup;
 test_run("kprobe");
 bpf_link__destroy(link);

 /* attach kretprobe */
 link = bpf_program__attach_kprobe(kretprobe_prog, true /* retprobe */,
       kprobe_func);
 if (!ASSERT_OK_PTR(link, "attach_kretprobe"))
  goto cleanup;
 test_run("kretprobe");
 bpf_link__destroy(link);

 /* attach raw_tp */
 link = bpf_program__attach_raw_tracepoint(raw_tp_prog, "task_rename");
 if (!ASSERT_OK_PTR(link, "attach_raw_tp"))
  goto cleanup;
 test_run("raw_tp");
 bpf_link__destroy(link);

 /* attach fentry */
 link = bpf_program__attach_trace(fentry_prog);
 if (!ASSERT_OK_PTR(link, "attach_fentry"))
  goto cleanup;
 test_run("fentry");
 bpf_link__destroy(link);

 /* attach fexit */
 link = bpf_program__attach_trace(fexit_prog);
 if (!ASSERT_OK_PTR(link, "attach_fexit"))
  goto cleanup;
 test_run("fexit");
 bpf_link__destroy(link);

cleanup:
 prctl(PR_SET_NAME, comm, 0L, 0L, 0L);
 bpf_object__close(obj);
}