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 #include <stdio.h> 8 #include <unistd.h> 9 #include <stdlib.h> 10 #include <stdbool.h> 11 #include <string.h> 12 #include <fcntl.h> 13 #include <poll.h> 14 #include <sys/ioctl.h> 15 #include <linux/perf_event.h> 16 #include <linux/bpf.h> 17 #include <signal.h> 18 #include <assert.h> 19 #include <errno.h> 20 #include <sys/resource.h> 21 #include "libbpf.h" 22 #include "bpf_load.h" 23 24 #define SAMPLE_FREQ 50 25 26 static bool sys_read_seen, sys_write_seen; 27 28 static void print_ksym(__u64 addr) 29 { 30 struct ksym *sym; 31 32 if (!addr) 33 return; 34 sym = ksym_search(addr); 35 printf("%s;", sym->name); 36 if (!strcmp(sym->name, "sys_read")) 37 sys_read_seen = true; 38 else if (!strcmp(sym->name, "sys_write")) 39 sys_write_seen = true; 40 } 41 42 static void print_addr(__u64 addr) 43 { 44 if (!addr) 45 return; 46 printf("%llx;", addr); 47 } 48 49 #define TASK_COMM_LEN 16 50 51 struct key_t { 52 char comm[TASK_COMM_LEN]; 53 __u32 kernstack; 54 __u32 userstack; 55 }; 56 57 static void print_stack(struct key_t *key, __u64 count) 58 { 59 __u64 ip[PERF_MAX_STACK_DEPTH] = {}; 60 static bool warned; 61 int i; 62 63 printf("%3lld %s;", count, key->comm); 64 if (bpf_lookup_elem(map_fd[1], &key->kernstack, ip) != 0) { 65 printf("---;"); 66 } else { 67 for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--) 68 print_ksym(ip[i]); 69 } 70 printf("-;"); 71 if (bpf_lookup_elem(map_fd[1], &key->userstack, ip) != 0) { 72 printf("---;"); 73 } else { 74 for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--) 75 print_addr(ip[i]); 76 } 77 printf("\n"); 78 79 if (key->kernstack == -EEXIST && !warned) { 80 printf("stackmap collisions seen. Consider increasing size\n"); 81 warned = true; 82 } else if ((int)key->kernstack < 0 && (int)key->userstack < 0) { 83 printf("err stackid %d %d\n", key->kernstack, key->userstack); 84 } 85 } 86 87 static void int_exit(int sig) 88 { 89 kill(0, SIGKILL); 90 exit(0); 91 } 92 93 static void print_stacks(void) 94 { 95 struct key_t key = {}, next_key; 96 __u64 value; 97 __u32 stackid = 0, next_id; 98 int fd = map_fd[0], stack_map = map_fd[1]; 99 100 sys_read_seen = sys_write_seen = false; 101 while (bpf_get_next_key(fd, &key, &next_key) == 0) { 102 bpf_lookup_elem(fd, &next_key, &value); 103 print_stack(&next_key, value); 104 bpf_delete_elem(fd, &next_key); 105 key = next_key; 106 } 107 108 if (!sys_read_seen || !sys_write_seen) { 109 printf("BUG kernel stack doesn't contain sys_read() and sys_write()\n"); 110 int_exit(0); 111 } 112 113 /* clear stack map */ 114 while (bpf_get_next_key(stack_map, &stackid, &next_id) == 0) { 115 bpf_delete_elem(stack_map, &next_id); 116 stackid = next_id; 117 } 118 } 119 120 static void test_perf_event_all_cpu(struct perf_event_attr *attr) 121 { 122 int nr_cpus = sysconf(_SC_NPROCESSORS_CONF); 123 int *pmu_fd = malloc(nr_cpus * sizeof(int)); 124 int i; 125 126 /* open perf_event on all cpus */ 127 for (i = 0; i < nr_cpus; i++) { 128 pmu_fd[i] = perf_event_open(attr, -1, i, -1, 0); 129 if (pmu_fd[i] < 0) { 130 printf("perf_event_open failed\n"); 131 goto all_cpu_err; 132 } 133 assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0); 134 assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE, 0) == 0); 135 } 136 system("dd if=/dev/zero of=/dev/null count=5000k"); 137 print_stacks(); 138 all_cpu_err: 139 for (i--; i >= 0; i--) 140 close(pmu_fd[i]); 141 free(pmu_fd); 142 } 143 144 static void test_perf_event_task(struct perf_event_attr *attr) 145 { 146 int pmu_fd; 147 148 /* open task bound event */ 149 pmu_fd = perf_event_open(attr, 0, -1, -1, 0); 150 if (pmu_fd < 0) { 151 printf("perf_event_open failed\n"); 152 return; 153 } 154 assert(ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0); 155 assert(ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0) == 0); 156 system("dd if=/dev/zero of=/dev/null count=5000k"); 157 print_stacks(); 158 close(pmu_fd); 159 } 160 161 static void test_bpf_perf_event(void) 162 { 163 struct perf_event_attr attr_type_hw = { 164 .sample_freq = SAMPLE_FREQ, 165 .freq = 1, 166 .type = PERF_TYPE_HARDWARE, 167 .config = PERF_COUNT_HW_CPU_CYCLES, 168 .inherit = 1, 169 }; 170 struct perf_event_attr attr_type_sw = { 171 .sample_freq = SAMPLE_FREQ, 172 .freq = 1, 173 .type = PERF_TYPE_SOFTWARE, 174 .config = PERF_COUNT_SW_CPU_CLOCK, 175 .inherit = 1, 176 }; 177 178 test_perf_event_all_cpu(&attr_type_hw); 179 test_perf_event_task(&attr_type_hw); 180 test_perf_event_all_cpu(&attr_type_sw); 181 test_perf_event_task(&attr_type_sw); 182 } 183 184 185 int main(int argc, char **argv) 186 { 187 struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY}; 188 char filename[256]; 189 190 snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); 191 setrlimit(RLIMIT_MEMLOCK, &r); 192 193 signal(SIGINT, int_exit); 194 195 if (load_kallsyms()) { 196 printf("failed to process /proc/kallsyms\n"); 197 return 1; 198 } 199 200 if (load_bpf_file(filename)) { 201 printf("%s", bpf_log_buf); 202 return 2; 203 } 204 205 if (fork() == 0) { 206 read_trace_pipe(); 207 return 0; 208 } 209 test_bpf_perf_event(); 210 211 int_exit(0); 212 return 0; 213 } 214