1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (c) 2016 Facebook 4 */ 5 #define _GNU_SOURCE 6 #include <linux/types.h> 7 #include <stdio.h> 8 #include <unistd.h> 9 #include <linux/bpf.h> 10 #include <errno.h> 11 #include <string.h> 12 #include <assert.h> 13 #include <sched.h> 14 #include <sys/wait.h> 15 #include <sys/stat.h> 16 #include <sys/resource.h> 17 #include <fcntl.h> 18 #include <stdlib.h> 19 #include <time.h> 20 21 #include <bpf/bpf.h> 22 #include "bpf_util.h" 23 24 #define min(a, b) ((a) < (b) ? (a) : (b)) 25 #ifndef offsetof 26 # define offsetof(TYPE, MEMBER) ((size_t)&((TYPE *)0)->MEMBER) 27 #endif 28 #define container_of(ptr, type, member) ({ \ 29 const typeof( ((type *)0)->member ) *__mptr = (ptr); \ 30 (type *)( (char *)__mptr - offsetof(type,member) );}) 31 32 static int nr_cpus; 33 static unsigned long long *dist_keys; 34 static unsigned int dist_key_counts; 35 36 struct list_head { 37 struct list_head *next, *prev; 38 }; 39 40 static inline void INIT_LIST_HEAD(struct list_head *list) 41 { 42 list->next = list; 43 list->prev = list; 44 } 45 46 static inline int list_empty(const struct list_head *head) 47 { 48 return head->next == head; 49 } 50 51 static inline void __list_add(struct list_head *new, 52 struct list_head *prev, 53 struct list_head *next) 54 { 55 next->prev = new; 56 new->next = next; 57 new->prev = prev; 58 prev->next = new; 59 } 60 61 static inline void list_add(struct list_head *new, struct list_head *head) 62 { 63 __list_add(new, head, head->next); 64 } 65 66 static inline void __list_del(struct list_head *prev, struct list_head *next) 67 { 68 next->prev = prev; 69 prev->next = next; 70 } 71 72 static inline void __list_del_entry(struct list_head *entry) 73 { 74 __list_del(entry->prev, entry->next); 75 } 76 77 static inline void list_move(struct list_head *list, struct list_head *head) 78 { 79 __list_del_entry(list); 80 list_add(list, head); 81 } 82 83 #define list_entry(ptr, type, member) \ 84 container_of(ptr, type, member) 85 86 #define list_last_entry(ptr, type, member) \ 87 list_entry((ptr)->prev, type, member) 88 89 struct pfect_lru_node { 90 struct list_head list; 91 unsigned long long key; 92 }; 93 94 struct pfect_lru { 95 struct list_head list; 96 struct pfect_lru_node *free_nodes; 97 unsigned int cur_size; 98 unsigned int lru_size; 99 unsigned int nr_unique; 100 unsigned int nr_misses; 101 unsigned int total; 102 int map_fd; 103 }; 104 105 static void pfect_lru_init(struct pfect_lru *lru, unsigned int lru_size, 106 unsigned int nr_possible_elems) 107 { 108 lru->map_fd = bpf_map_create(BPF_MAP_TYPE_HASH, NULL, 109 sizeof(unsigned long long), 110 sizeof(struct pfect_lru_node *), 111 nr_possible_elems, NULL); 112 assert(lru->map_fd != -1); 113 114 lru->free_nodes = malloc(lru_size * sizeof(struct pfect_lru_node)); 115 assert(lru->free_nodes); 116 117 INIT_LIST_HEAD(&lru->list); 118 lru->cur_size = 0; 119 lru->lru_size = lru_size; 120 lru->nr_unique = lru->nr_misses = lru->total = 0; 121 } 122 123 static void pfect_lru_destroy(struct pfect_lru *lru) 124 { 125 close(lru->map_fd); 126 free(lru->free_nodes); 127 } 128 129 static int pfect_lru_lookup_or_insert(struct pfect_lru *lru, 130 unsigned long long key) 131 { 132 struct pfect_lru_node *node = NULL; 133 int seen = 0; 134 135 lru->total++; 136 if (!bpf_map_lookup_elem(lru->map_fd, &key, &node)) { 137 if (node) { 138 list_move(&node->list, &lru->list); 139 return 1; 140 } 141 seen = 1; 142 } 143 144 if (lru->cur_size < lru->lru_size) { 145 node = &lru->free_nodes[lru->cur_size++]; 146 INIT_LIST_HEAD(&node->list); 147 } else { 148 struct pfect_lru_node *null_node = NULL; 149 150 node = list_last_entry(&lru->list, 151 struct pfect_lru_node, 152 list); 153 bpf_map_update_elem(lru->map_fd, &node->key, &null_node, BPF_EXIST); 154 } 155 156 node->key = key; 157 list_move(&node->list, &lru->list); 158 159 lru->nr_misses++; 160 if (seen) { 161 assert(!bpf_map_update_elem(lru->map_fd, &key, &node, BPF_EXIST)); 162 } else { 163 lru->nr_unique++; 164 assert(!bpf_map_update_elem(lru->map_fd, &key, &node, BPF_NOEXIST)); 165 } 166 167 return seen; 168 } 169 170 static unsigned int read_keys(const char *dist_file, 171 unsigned long long **keys) 172 { 173 struct stat fst; 174 unsigned long long *retkeys; 175 unsigned int counts = 0; 176 int dist_fd; 177 char *b, *l; 178 int i; 179 180 dist_fd = open(dist_file, 0); 181 assert(dist_fd != -1); 182 183 assert(fstat(dist_fd, &fst) == 0); 184 b = malloc(fst.st_size); 185 assert(b); 186 187 assert(read(dist_fd, b, fst.st_size) == fst.st_size); 188 close(dist_fd); 189 for (i = 0; i < fst.st_size; i++) { 190 if (b[i] == '\n') 191 counts++; 192 } 193 counts++; /* in case the last line has no \n */ 194 195 retkeys = malloc(counts * sizeof(unsigned long long)); 196 assert(retkeys); 197 198 counts = 0; 199 for (l = strtok(b, "\n"); l; l = strtok(NULL, "\n")) 200 retkeys[counts++] = strtoull(l, NULL, 10); 201 free(b); 202 203 *keys = retkeys; 204 205 return counts; 206 } 207 208 static int create_map(int map_type, int map_flags, unsigned int size) 209 { 210 LIBBPF_OPTS(bpf_map_create_opts, opts, 211 .map_flags = map_flags, 212 ); 213 int map_fd; 214 215 map_fd = bpf_map_create(map_type, NULL, sizeof(unsigned long long), 216 sizeof(unsigned long long), size, &opts); 217 218 if (map_fd == -1) 219 perror("bpf_create_map"); 220 221 return map_fd; 222 } 223 224 static int sched_next_online(int pid, int next_to_try) 225 { 226 cpu_set_t cpuset; 227 228 if (next_to_try == nr_cpus) 229 return -1; 230 231 while (next_to_try < nr_cpus) { 232 CPU_ZERO(&cpuset); 233 CPU_SET(next_to_try++, &cpuset); 234 if (!sched_setaffinity(pid, sizeof(cpuset), &cpuset)) 235 break; 236 } 237 238 return next_to_try; 239 } 240 241 static void run_parallel(unsigned int tasks, void (*fn)(int i, void *data), 242 void *data) 243 { 244 int next_sched_cpu = 0; 245 pid_t pid[tasks]; 246 int i; 247 248 for (i = 0; i < tasks; i++) { 249 pid[i] = fork(); 250 if (pid[i] == 0) { 251 next_sched_cpu = sched_next_online(0, next_sched_cpu); 252 fn(i, data); 253 exit(0); 254 } else if (pid[i] == -1) { 255 printf("couldn't spawn #%d process\n", i); 256 exit(1); 257 } 258 /* It is mostly redundant and just allow the parent 259 * process to update next_shced_cpu for the next child 260 * process 261 */ 262 next_sched_cpu = sched_next_online(pid[i], next_sched_cpu); 263 } 264 for (i = 0; i < tasks; i++) { 265 int status; 266 267 assert(waitpid(pid[i], &status, 0) == pid[i]); 268 assert(status == 0); 269 } 270 } 271 272 static void do_test_lru_dist(int task, void *data) 273 { 274 unsigned int nr_misses = 0; 275 struct pfect_lru pfect_lru; 276 unsigned long long key, value = 1234; 277 unsigned int i; 278 279 unsigned int lru_map_fd = ((unsigned int *)data)[0]; 280 unsigned int lru_size = ((unsigned int *)data)[1]; 281 unsigned long long key_offset = task * dist_key_counts; 282 283 pfect_lru_init(&pfect_lru, lru_size, dist_key_counts); 284 285 for (i = 0; i < dist_key_counts; i++) { 286 key = dist_keys[i] + key_offset; 287 288 pfect_lru_lookup_or_insert(&pfect_lru, key); 289 290 if (!bpf_map_lookup_elem(lru_map_fd, &key, &value)) 291 continue; 292 293 if (bpf_map_update_elem(lru_map_fd, &key, &value, BPF_NOEXIST)) { 294 printf("bpf_map_update_elem(lru_map_fd, %llu): errno:%d\n", 295 key, errno); 296 assert(0); 297 } 298 299 nr_misses++; 300 } 301 302 printf(" task:%d BPF LRU: nr_unique:%u(/%u) nr_misses:%u(/%u)\n", 303 task, pfect_lru.nr_unique, dist_key_counts, nr_misses, 304 dist_key_counts); 305 printf(" task:%d Perfect LRU: nr_unique:%u(/%u) nr_misses:%u(/%u)\n", 306 task, pfect_lru.nr_unique, pfect_lru.total, 307 pfect_lru.nr_misses, pfect_lru.total); 308 309 pfect_lru_destroy(&pfect_lru); 310 close(lru_map_fd); 311 } 312 313 static void test_parallel_lru_dist(int map_type, int map_flags, 314 int nr_tasks, unsigned int lru_size) 315 { 316 int child_data[2]; 317 int lru_map_fd; 318 319 printf("%s (map_type:%d map_flags:0x%X):\n", __func__, map_type, 320 map_flags); 321 322 if (map_flags & BPF_F_NO_COMMON_LRU) 323 lru_map_fd = create_map(map_type, map_flags, 324 nr_cpus * lru_size); 325 else 326 lru_map_fd = create_map(map_type, map_flags, 327 nr_tasks * lru_size); 328 assert(lru_map_fd != -1); 329 330 child_data[0] = lru_map_fd; 331 child_data[1] = lru_size; 332 333 run_parallel(nr_tasks, do_test_lru_dist, child_data); 334 335 close(lru_map_fd); 336 } 337 338 static void test_lru_loss0(int map_type, int map_flags) 339 { 340 unsigned long long key, value[nr_cpus]; 341 unsigned int old_unused_losses = 0; 342 unsigned int new_unused_losses = 0; 343 unsigned int used_losses = 0; 344 int map_fd; 345 346 printf("%s (map_type:%d map_flags:0x%X): ", __func__, map_type, 347 map_flags); 348 349 assert(sched_next_online(0, 0) != -1); 350 351 if (map_flags & BPF_F_NO_COMMON_LRU) 352 map_fd = create_map(map_type, map_flags, 900 * nr_cpus); 353 else 354 map_fd = create_map(map_type, map_flags, 900); 355 356 assert(map_fd != -1); 357 358 value[0] = 1234; 359 360 for (key = 1; key <= 1000; key++) { 361 int start_key, end_key; 362 363 assert(bpf_map_update_elem(map_fd, &key, value, BPF_NOEXIST) == 0); 364 365 start_key = 101; 366 end_key = min(key, 900); 367 368 while (start_key <= end_key) { 369 bpf_map_lookup_elem(map_fd, &start_key, value); 370 start_key++; 371 } 372 } 373 374 for (key = 1; key <= 1000; key++) { 375 if (bpf_map_lookup_elem(map_fd, &key, value)) { 376 if (key <= 100) 377 old_unused_losses++; 378 else if (key <= 900) 379 used_losses++; 380 else 381 new_unused_losses++; 382 } 383 } 384 385 close(map_fd); 386 387 printf("older-elem-losses:%d(/100) active-elem-losses:%d(/800) " 388 "newer-elem-losses:%d(/100)\n", 389 old_unused_losses, used_losses, new_unused_losses); 390 } 391 392 static void test_lru_loss1(int map_type, int map_flags) 393 { 394 unsigned long long key, value[nr_cpus]; 395 int map_fd; 396 unsigned int nr_losses = 0; 397 398 printf("%s (map_type:%d map_flags:0x%X): ", __func__, map_type, 399 map_flags); 400 401 assert(sched_next_online(0, 0) != -1); 402 403 if (map_flags & BPF_F_NO_COMMON_LRU) 404 map_fd = create_map(map_type, map_flags, 1000 * nr_cpus); 405 else 406 map_fd = create_map(map_type, map_flags, 1000); 407 408 assert(map_fd != -1); 409 410 value[0] = 1234; 411 412 for (key = 1; key <= 1000; key++) 413 assert(!bpf_map_update_elem(map_fd, &key, value, BPF_NOEXIST)); 414 415 for (key = 1; key <= 1000; key++) { 416 if (bpf_map_lookup_elem(map_fd, &key, value)) 417 nr_losses++; 418 } 419 420 close(map_fd); 421 422 printf("nr_losses:%d(/1000)\n", nr_losses); 423 } 424 425 static void do_test_parallel_lru_loss(int task, void *data) 426 { 427 const unsigned int nr_stable_elems = 1000; 428 const unsigned int nr_repeats = 100000; 429 430 int map_fd = *(int *)data; 431 unsigned long long stable_base; 432 unsigned long long key, value[nr_cpus]; 433 unsigned long long next_ins_key; 434 unsigned int nr_losses = 0; 435 unsigned int i; 436 437 stable_base = task * nr_repeats * 2 + 1; 438 next_ins_key = stable_base; 439 value[0] = 1234; 440 for (i = 0; i < nr_stable_elems; i++) { 441 assert(bpf_map_update_elem(map_fd, &next_ins_key, value, 442 BPF_NOEXIST) == 0); 443 next_ins_key++; 444 } 445 446 for (i = 0; i < nr_repeats; i++) { 447 int rn; 448 449 rn = rand(); 450 451 if (rn % 10) { 452 key = rn % nr_stable_elems + stable_base; 453 bpf_map_lookup_elem(map_fd, &key, value); 454 } else { 455 bpf_map_update_elem(map_fd, &next_ins_key, value, 456 BPF_NOEXIST); 457 next_ins_key++; 458 } 459 } 460 461 key = stable_base; 462 for (i = 0; i < nr_stable_elems; i++) { 463 if (bpf_map_lookup_elem(map_fd, &key, value)) 464 nr_losses++; 465 key++; 466 } 467 468 printf(" task:%d nr_losses:%u\n", task, nr_losses); 469 } 470 471 static void test_parallel_lru_loss(int map_type, int map_flags, int nr_tasks) 472 { 473 int map_fd; 474 475 printf("%s (map_type:%d map_flags:0x%X):\n", __func__, map_type, 476 map_flags); 477 478 /* Give 20% more than the active working set */ 479 if (map_flags & BPF_F_NO_COMMON_LRU) 480 map_fd = create_map(map_type, map_flags, 481 nr_cpus * (1000 + 200)); 482 else 483 map_fd = create_map(map_type, map_flags, 484 nr_tasks * (1000 + 200)); 485 486 assert(map_fd != -1); 487 488 run_parallel(nr_tasks, do_test_parallel_lru_loss, &map_fd); 489 490 close(map_fd); 491 } 492 493 int main(int argc, char **argv) 494 { 495 int map_flags[] = {0, BPF_F_NO_COMMON_LRU}; 496 const char *dist_file; 497 int nr_tasks = 1; 498 int lru_size; 499 int f; 500 501 if (argc < 4) { 502 printf("Usage: %s <dist-file> <lru-size> <nr-tasks>\n", 503 argv[0]); 504 return -1; 505 } 506 507 dist_file = argv[1]; 508 lru_size = atoi(argv[2]); 509 nr_tasks = atoi(argv[3]); 510 511 setbuf(stdout, NULL); 512 513 srand(time(NULL)); 514 515 nr_cpus = bpf_num_possible_cpus(); 516 assert(nr_cpus != -1); 517 printf("nr_cpus:%d\n\n", nr_cpus); 518 519 nr_tasks = min(nr_tasks, nr_cpus); 520 521 dist_key_counts = read_keys(dist_file, &dist_keys); 522 if (!dist_key_counts) { 523 printf("%s has no key\n", dist_file); 524 return -1; 525 } 526 527 for (f = 0; f < sizeof(map_flags) / sizeof(*map_flags); f++) { 528 test_lru_loss0(BPF_MAP_TYPE_LRU_HASH, map_flags[f]); 529 test_lru_loss1(BPF_MAP_TYPE_LRU_HASH, map_flags[f]); 530 test_parallel_lru_loss(BPF_MAP_TYPE_LRU_HASH, map_flags[f], 531 nr_tasks); 532 test_parallel_lru_dist(BPF_MAP_TYPE_LRU_HASH, map_flags[f], 533 nr_tasks, lru_size); 534 printf("\n"); 535 } 536 537 free(dist_keys); 538 539 return 0; 540 } 541