samples/bpf/test_overhead_user.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* Copyright (c) 2016 Facebook
   3  */
   4 #define _GNU_SOURCE
   5 #include <sched.h>
   6 #include <errno.h>
   7 #include <stdio.h>
   8 #include <sys/types.h>
   9 #include <asm/unistd.h>
  10 #include <fcntl.h>
  11 #include <unistd.h>
  12 #include <assert.h>
  13 #include <sys/wait.h>
  14 #include <stdlib.h>
  15 #include <signal.h>
  16 #include <linux/bpf.h>
  17 #include <string.h>
  18 #include <time.h>
  19 #include <sys/resource.h>
  20 #include <bpf/bpf.h>
  21 #include "bpf_load.h"
  22
  23 #define MAX_CNT 1000000
  24
  25 static __u64 time_get_ns(void)
  26 {
  27         struct timespec ts;
  28
  29         clock_gettime(CLOCK_MONOTONIC, &ts);
  30         return ts.tv_sec * 1000000000ull + ts.tv_nsec;
  31 }
  32
  33 static void test_task_rename(int cpu)
  34 {
  35         __u64 start_time;
  36         char buf[] = "test\n";
  37         int i, fd;
  38
  39         fd = open("/proc/self/comm", O_WRONLY|O_TRUNC);
  40         if (fd < 0) {
  41                 printf("couldn't open /proc\n");
  42                 exit(1);
  43         }
  44         start_time = time_get_ns();
  45         for (i = 0; i < MAX_CNT; i++) {
  46                 if (write(fd, buf, sizeof(buf)) < 0) {
  47                         printf("task rename failed: %s\n", strerror(errno));
  48                         close(fd);
  49                         return;
  50                 }
  51         }
  52         printf("task_rename:%d: %lld events per sec\n",
  53                cpu, MAX_CNT * 1000000000ll / (time_get_ns() - start_time));
  54         close(fd);
  55 }
  56
  57 static void test_urandom_read(int cpu)
  58 {
  59         __u64 start_time;
  60         char buf[4];
  61         int i, fd;
  62
  63         fd = open("/dev/urandom", O_RDONLY);
  64         if (fd < 0) {
  65                 printf("couldn't open /dev/urandom\n");
  66                 exit(1);
  67         }
  68         start_time = time_get_ns();
  69         for (i = 0; i < MAX_CNT; i++) {
  70                 if (read(fd, buf, sizeof(buf)) < 0) {
  71                         printf("failed to read from /dev/urandom: %s\n", strerror(errno));
  72                         close(fd);
  73                         return;
  74                 }
  75         }
  76         printf("urandom_read:%d: %lld events per sec\n",
  77                cpu, MAX_CNT * 1000000000ll / (time_get_ns() - start_time));
  78         close(fd);
  79 }
  80
  81 static void loop(int cpu, int flags)
  82 {
  83         cpu_set_t cpuset;
  84
  85         CPU_ZERO(&cpuset);
  86         CPU_SET(cpu, &cpuset);
  87         sched_setaffinity(0, sizeof(cpuset), &cpuset);
  88
  89         if (flags & 1)
  90                 test_task_rename(cpu);
  91         if (flags & 2)
  92                 test_urandom_read(cpu);
  93 }
  94
  95 static void run_perf_test(int tasks, int flags)
  96 {
  97         pid_t pid[tasks];
  98         int i;
  99
 100         for (i = 0; i < tasks; i++) {
 101                 pid[i] = fork();
 102                 if (pid[i] == 0) {
 103                         loop(i, flags);
 104                         exit(0);
 105                 } else if (pid[i] == -1) {
 106                         printf("couldn't spawn #%d process\n", i);
 107                         exit(1);
 108                 }
 109         }
 110         for (i = 0; i < tasks; i++) {
 111                 int status;
 112
 113                 assert(waitpid(pid[i], &status, 0) == pid[i]);
 114                 assert(status == 0);
 115         }
 116 }
 117
 118 static void unload_progs(void)
 119 {
 120         close(prog_fd[0]);
 121         close(prog_fd[1]);
 122         close(event_fd[0]);
 123         close(event_fd[1]);
 124 }
 125
 126 int main(int argc, char **argv)
 127 {
 128         struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
 129         char filename[256];
 130         int num_cpu = 8;
 131         int test_flags = ~0;
 132
 133         setrlimit(RLIMIT_MEMLOCK, &r);
 134
 135         if (argc > 1)
 136                 test_flags = atoi(argv[1]) ? : test_flags;
 137         if (argc > 2)
 138                 num_cpu = atoi(argv[2]) ? : num_cpu;
 139
 140         if (test_flags & 0x3) {
 141                 printf("BASE\n");
 142                 run_perf_test(num_cpu, test_flags);
 143         }
 144
 145         if (test_flags & 0xC) {
 146                 snprintf(filename, sizeof(filename),
 147                          "%s_kprobe_kern.o", argv[0]);
 148                 if (load_bpf_file(filename)) {
 149                         printf("%s", bpf_log_buf);
 150                         return 1;
 151                 }
 152                 printf("w/KPROBE\n");
 153                 run_perf_test(num_cpu, test_flags >> 2);
 154                 unload_progs();
 155         }
 156
 157         if (test_flags & 0x30) {
 158                 snprintf(filename, sizeof(filename),
 159                          "%s_tp_kern.o", argv[0]);
 160                 if (load_bpf_file(filename)) {
 161                         printf("%s", bpf_log_buf);
 162                         return 1;
 163                 }
 164                 printf("w/TRACEPOINT\n");
 165                 run_perf_test(num_cpu, test_flags >> 4);
 166                 unload_progs();
 167         }
 168
 169         if (test_flags & 0xC0) {
 170                 snprintf(filename, sizeof(filename),
 171                          "%s_raw_tp_kern.o", argv[0]);
 172                 if (load_bpf_file(filename)) {
 173                         printf("%s", bpf_log_buf);
 174                         return 1;
 175                 }
 176                 printf("w/RAW_TRACEPOINT\n");
 177                 run_perf_test(num_cpu, test_flags >> 6);
 178                 unload_progs();
 179         }
 180
 181         return 0;
 182 }