samples/bpf/test_overhead_user.c

   1 /* Copyright (c) 2016 Facebook
   2  *
   3  * This program is free software; you can redistribute it and/or
   4  * modify it under the terms of version 2 of the GNU General Public
   5  * License as published by the Free Software Foundation.
   6  */
   7 #define _GNU_SOURCE
   8 #include <sched.h>
   9 #include <errno.h>
  10 #include <stdio.h>
  11 #include <sys/types.h>
  12 #include <asm/unistd.h>
  13 #include <fcntl.h>
  14 #include <unistd.h>
  15 #include <assert.h>
  16 #include <sys/wait.h>
  17 #include <stdlib.h>
  18 #include <signal.h>
  19 #include <linux/bpf.h>
  20 #include <string.h>
  21 #include <time.h>
  22 #include <sys/resource.h>
  23 #include <bpf/bpf.h>
  24 #include "bpf_load.h"
  25
  26 #define MAX_CNT 1000000
  27
  28 static __u64 time_get_ns(void)
  29 {
  30         struct timespec ts;
  31
  32         clock_gettime(CLOCK_MONOTONIC, &ts);
  33         return ts.tv_sec * 1000000000ull + ts.tv_nsec;
  34 }
  35
  36 static void test_task_rename(int cpu)
  37 {
  38         __u64 start_time;
  39         char buf[] = "test\n";
  40         int i, fd;
  41
  42         fd = open("/proc/self/comm", O_WRONLY|O_TRUNC);
  43         if (fd < 0) {
  44                 printf("couldn't open /proc\n");
  45                 exit(1);
  46         }
  47         start_time = time_get_ns();
  48         for (i = 0; i < MAX_CNT; i++) {
  49                 if (write(fd, buf, sizeof(buf)) < 0) {
  50                         printf("task rename failed: %s\n", strerror(errno));
  51                         close(fd);
  52                         return;
  53                 }
  54         }
  55         printf("task_rename:%d: %lld events per sec\n",
  56                cpu, MAX_CNT * 1000000000ll / (time_get_ns() - start_time));
  57         close(fd);
  58 }
  59
  60 static void test_urandom_read(int cpu)
  61 {
  62         __u64 start_time;
  63         char buf[4];
  64         int i, fd;
  65
  66         fd = open("/dev/urandom", O_RDONLY);
  67         if (fd < 0) {
  68                 printf("couldn't open /dev/urandom\n");
  69                 exit(1);
  70         }
  71         start_time = time_get_ns();
  72         for (i = 0; i < MAX_CNT; i++) {
  73                 if (read(fd, buf, sizeof(buf)) < 0) {
  74                         printf("failed to read from /dev/urandom: %s\n", strerror(errno));
  75                         close(fd);
  76                         return;
  77                 }
  78         }
  79         printf("urandom_read:%d: %lld events per sec\n",
  80                cpu, MAX_CNT * 1000000000ll / (time_get_ns() - start_time));
  81         close(fd);
  82 }
  83
  84 static void loop(int cpu, int flags)
  85 {
  86         cpu_set_t cpuset;
  87
  88         CPU_ZERO(&cpuset);
  89         CPU_SET(cpu, &cpuset);
  90         sched_setaffinity(0, sizeof(cpuset), &cpuset);
  91
  92         if (flags & 1)
  93                 test_task_rename(cpu);
  94         if (flags & 2)
  95                 test_urandom_read(cpu);
  96 }
  97
  98 static void run_perf_test(int tasks, int flags)
  99 {
 100         pid_t pid[tasks];
 101         int i;
 102
 103         for (i = 0; i < tasks; i++) {
 104                 pid[i] = fork();
 105                 if (pid[i] == 0) {
 106                         loop(i, flags);
 107                         exit(0);
 108                 } else if (pid[i] == -1) {
 109                         printf("couldn't spawn #%d process\n", i);
 110                         exit(1);
 111                 }
 112         }
 113         for (i = 0; i < tasks; i++) {
 114                 int status;
 115
 116                 assert(waitpid(pid[i], &status, 0) == pid[i]);
 117                 assert(status == 0);
 118         }
 119 }
 120
 121 static void unload_progs(void)
 122 {
 123         close(prog_fd[0]);
 124         close(prog_fd[1]);
 125         close(event_fd[0]);
 126         close(event_fd[1]);
 127 }
 128
 129 int main(int argc, char **argv)
 130 {
 131         struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
 132         char filename[256];
 133         int num_cpu = 8;
 134         int test_flags = ~0;
 135
 136         setrlimit(RLIMIT_MEMLOCK, &r);
 137
 138         if (argc > 1)
 139                 test_flags = atoi(argv[1]) ? : test_flags;
 140         if (argc > 2)
 141                 num_cpu = atoi(argv[2]) ? : num_cpu;
 142
 143         if (test_flags & 0x3) {
 144                 printf("BASE\n");
 145                 run_perf_test(num_cpu, test_flags);
 146         }
 147
 148         if (test_flags & 0xC) {
 149                 snprintf(filename, sizeof(filename),
 150                          "%s_kprobe_kern.o", argv[0]);
 151                 if (load_bpf_file(filename)) {
 152                         printf("%s", bpf_log_buf);
 153                         return 1;
 154                 }
 155                 printf("w/KPROBE\n");
 156                 run_perf_test(num_cpu, test_flags >> 2);
 157                 unload_progs();
 158         }
 159
 160         if (test_flags & 0x30) {
 161                 snprintf(filename, sizeof(filename),
 162                          "%s_tp_kern.o", argv[0]);
 163                 if (load_bpf_file(filename)) {
 164                         printf("%s", bpf_log_buf);
 165                         return 1;
 166                 }
 167                 printf("w/TRACEPOINT\n");
 168                 run_perf_test(num_cpu, test_flags >> 4);
 169                 unload_progs();
 170         }
 171
 172         if (test_flags & 0xC0) {
 173                 snprintf(filename, sizeof(filename),
 174                          "%s_raw_tp_kern.o", argv[0]);
 175                 if (load_bpf_file(filename)) {
 176                         printf("%s", bpf_log_buf);
 177                         return 1;
 178                 }
 179                 printf("w/RAW_TRACEPOINT\n");
 180                 run_perf_test(num_cpu, test_flags >> 6);
 181                 unload_progs();
 182         }
 183
 184         return 0;
 185 }