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