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 #include "perf-sys.h" 24 25 #define SAMPLE_FREQ 50 26 27 static bool sys_read_seen, sys_write_seen; 28 29 static void print_ksym(__u64 addr) 30 { 31 struct ksym *sym; 32 33 if (!addr) 34 return; 35 sym = ksym_search(addr); 36 printf("%s;", sym->name); 37 if (!strcmp(sym->name, "sys_read")) 38 sys_read_seen = true; 39 else if (!strcmp(sym->name, "sys_write")) 40 sys_write_seen = true; 41 } 42 43 static void print_addr(__u64 addr) 44 { 45 if (!addr) 46 return; 47 printf("%llx;", addr); 48 } 49 50 #define TASK_COMM_LEN 16 51 52 struct key_t { 53 char comm[TASK_COMM_LEN]; 54 __u32 kernstack; 55 __u32 userstack; 56 }; 57 58 static void print_stack(struct key_t *key, __u64 count) 59 { 60 __u64 ip[PERF_MAX_STACK_DEPTH] = {}; 61 static bool warned; 62 int i; 63 64 printf("%3lld %s;", count, key->comm); 65 if (bpf_map_lookup_elem(map_fd[1], &key->kernstack, ip) != 0) { 66 printf("---;"); 67 } else { 68 for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--) 69 print_ksym(ip[i]); 70 } 71 printf("-;"); 72 if (bpf_map_lookup_elem(map_fd[1], &key->userstack, ip) != 0) { 73 printf("---;"); 74 } else { 75 for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--) 76 print_addr(ip[i]); 77 } 78 printf("\n"); 79 80 if (key->kernstack == -EEXIST && !warned) { 81 printf("stackmap collisions seen. Consider increasing size\n"); 82 warned = true; 83 } else if ((int)key->kernstack < 0 && (int)key->userstack < 0) { 84 printf("err stackid %d %d\n", key->kernstack, key->userstack); 85 } 86 } 87 88 static void int_exit(int sig) 89 { 90 kill(0, SIGKILL); 91 exit(0); 92 } 93 94 static void print_stacks(void) 95 { 96 struct key_t key = {}, next_key; 97 __u64 value; 98 __u32 stackid = 0, next_id; 99 int fd = map_fd[0], stack_map = map_fd[1]; 100 101 sys_read_seen = sys_write_seen = false; 102 while (bpf_map_get_next_key(fd, &key, &next_key) == 0) { 103 bpf_map_lookup_elem(fd, &next_key, &value); 104 print_stack(&next_key, value); 105 bpf_map_delete_elem(fd, &next_key); 106 key = next_key; 107 } 108 109 if (!sys_read_seen || !sys_write_seen) { 110 printf("BUG kernel stack doesn't contain sys_read() and sys_write()\n"); 111 int_exit(0); 112 } 113 114 /* clear stack map */ 115 while (bpf_map_get_next_key(stack_map, &stackid, &next_id) == 0) { 116 bpf_map_delete_elem(stack_map, &next_id); 117 stackid = next_id; 118 } 119 } 120 121 static void test_perf_event_all_cpu(struct perf_event_attr *attr) 122 { 123 int nr_cpus = sysconf(_SC_NPROCESSORS_CONF); 124 int *pmu_fd = malloc(nr_cpus * sizeof(int)); 125 int i; 126 127 /* open perf_event on all cpus */ 128 for (i = 0; i < nr_cpus; i++) { 129 pmu_fd[i] = sys_perf_event_open(attr, -1, i, -1, 0); 130 if (pmu_fd[i] < 0) { 131 printf("sys_perf_event_open failed\n"); 132 goto all_cpu_err; 133 } 134 assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0); 135 assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE, 0) == 0); 136 } 137 system("dd if=/dev/zero of=/dev/null count=5000k"); 138 print_stacks(); 139 all_cpu_err: 140 for (i--; i >= 0; i--) 141 close(pmu_fd[i]); 142 free(pmu_fd); 143 } 144 145 static void test_perf_event_task(struct perf_event_attr *attr) 146 { 147 int pmu_fd; 148 149 /* open task bound event */ 150 pmu_fd = sys_perf_event_open(attr, 0, -1, -1, 0); 151 if (pmu_fd < 0) { 152 printf("sys_perf_event_open failed\n"); 153 return; 154 } 155 assert(ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0); 156 assert(ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0) == 0); 157 system("dd if=/dev/zero of=/dev/null count=5000k"); 158 print_stacks(); 159 close(pmu_fd); 160 } 161 162 static void test_bpf_perf_event(void) 163 { 164 struct perf_event_attr attr_type_hw = { 165 .sample_freq = SAMPLE_FREQ, 166 .freq = 1, 167 .type = PERF_TYPE_HARDWARE, 168 .config = PERF_COUNT_HW_CPU_CYCLES, 169 .inherit = 1, 170 }; 171 struct perf_event_attr attr_type_sw = { 172 .sample_freq = SAMPLE_FREQ, 173 .freq = 1, 174 .type = PERF_TYPE_SOFTWARE, 175 .config = PERF_COUNT_SW_CPU_CLOCK, 176 .inherit = 1, 177 }; 178 179 test_perf_event_all_cpu(&attr_type_hw); 180 test_perf_event_task(&attr_type_hw); 181 test_perf_event_all_cpu(&attr_type_sw); 182 test_perf_event_task(&attr_type_sw); 183 } 184 185 186 int main(int argc, char **argv) 187 { 188 struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY}; 189 char filename[256]; 190 191 snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); 192 setrlimit(RLIMIT_MEMLOCK, &r); 193 194 signal(SIGINT, int_exit); 195 196 if (load_kallsyms()) { 197 printf("failed to process /proc/kallsyms\n"); 198 return 1; 199 } 200 201 if (load_bpf_file(filename)) { 202 printf("%s", bpf_log_buf); 203 return 2; 204 } 205 206 if (fork() == 0) { 207 read_trace_pipe(); 208 return 0; 209 } 210 test_bpf_perf_event(); 211 212 int_exit(0); 213 return 0; 214 } 215