lib/rbtree_test.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 #include <linux/module.h>
   3 #include <linux/moduleparam.h>
   4 #include <linux/rbtree_augmented.h>
   5 #include <linux/random.h>
   6 #include <linux/slab.h>
   7 #include <asm/timex.h>
   8
   9 #define __param(type, name, init, msg)          \
  10         static type name = init;                \
  11         module_param(name, type, 0444);         \
  12         MODULE_PARM_DESC(name, msg);
  13
  14 __param(int, nnodes, 100, "Number of nodes in the rb-tree");
  15 __param(int, perf_loops, 1000, "Number of iterations modifying the rb-tree");
  16 __param(int, check_loops, 100, "Number of iterations modifying and verifying the rb-tree");
  17
  18 struct test_node {
  19         u32 key;
  20         struct rb_node rb;
  21
  22         /* following fields used for testing augmented rbtree functionality */
  23         u32 val;
  24         u32 augmented;
  25 };
  26
  27 static struct rb_root_cached root = RB_ROOT_CACHED;
  28 static struct test_node *nodes = NULL;
  29
  30 static struct rnd_state rnd;
  31
  32 static void insert(struct test_node *node, struct rb_root_cached *root)
  33 {
  34         struct rb_node **new = &root->rb_root.rb_node, *parent = NULL;
  35         u32 key = node->key;
  36
  37         while (*new) {
  38                 parent = *new;
  39                 if (key < rb_entry(parent, struct test_node, rb)->key)
  40                         new = &parent->rb_left;
  41                 else
  42                         new = &parent->rb_right;
  43         }
  44
  45         rb_link_node(&node->rb, parent, new);
  46         rb_insert_color(&node->rb, &root->rb_root);
  47 }
  48
  49 static void insert_cached(struct test_node *node, struct rb_root_cached *root)
  50 {
  51         struct rb_node **new = &root->rb_root.rb_node, *parent = NULL;
  52         u32 key = node->key;
  53         bool leftmost = true;
  54
  55         while (*new) {
  56                 parent = *new;
  57                 if (key < rb_entry(parent, struct test_node, rb)->key)
  58                         new = &parent->rb_left;
  59                 else {
  60                         new = &parent->rb_right;
  61                         leftmost = false;
  62                 }
  63         }
  64
  65         rb_link_node(&node->rb, parent, new);
  66         rb_insert_color_cached(&node->rb, root, leftmost);
  67 }
  68
  69 static inline void erase(struct test_node *node, struct rb_root_cached *root)
  70 {
  71         rb_erase(&node->rb, &root->rb_root);
  72 }
  73
  74 static inline void erase_cached(struct test_node *node, struct rb_root_cached *root)
  75 {
  76         rb_erase_cached(&node->rb, root);
  77 }
  78
  79
  80 static inline u32 augment_recompute(struct test_node *node)
  81 {
  82         u32 max = node->val, child_augmented;
  83         if (node->rb.rb_left) {
  84                 child_augmented = rb_entry(node->rb.rb_left, struct test_node,
  85                                            rb)->augmented;
  86                 if (max < child_augmented)
  87                         max = child_augmented;
  88         }
  89         if (node->rb.rb_right) {
  90                 child_augmented = rb_entry(node->rb.rb_right, struct test_node,
  91                                            rb)->augmented;
  92                 if (max < child_augmented)
  93                         max = child_augmented;
  94         }
  95         return max;
  96 }
  97
  98 RB_DECLARE_CALLBACKS(static, augment_callbacks, struct test_node, rb,
  99                      u32, augmented, augment_recompute)
 100
 101 static void insert_augmented(struct test_node *node,
 102                              struct rb_root_cached *root)
 103 {
 104         struct rb_node **new = &root->rb_root.rb_node, *rb_parent = NULL;
 105         u32 key = node->key;
 106         u32 val = node->val;
 107         struct test_node *parent;
 108
 109         while (*new) {
 110                 rb_parent = *new;
 111                 parent = rb_entry(rb_parent, struct test_node, rb);
 112                 if (parent->augmented < val)
 113                         parent->augmented = val;
 114                 if (key < parent->key)
 115                         new = &parent->rb.rb_left;
 116                 else
 117                         new = &parent->rb.rb_right;
 118         }
 119
 120         node->augmented = val;
 121         rb_link_node(&node->rb, rb_parent, new);
 122         rb_insert_augmented(&node->rb, &root->rb_root, &augment_callbacks);
 123 }
 124
 125 static void insert_augmented_cached(struct test_node *node,
 126                                     struct rb_root_cached *root)
 127 {
 128         struct rb_node **new = &root->rb_root.rb_node, *rb_parent = NULL;
 129         u32 key = node->key;
 130         u32 val = node->val;
 131         struct test_node *parent;
 132         bool leftmost = true;
 133
 134         while (*new) {
 135                 rb_parent = *new;
 136                 parent = rb_entry(rb_parent, struct test_node, rb);
 137                 if (parent->augmented < val)
 138                         parent->augmented = val;
 139                 if (key < parent->key)
 140                         new = &parent->rb.rb_left;
 141                 else {
 142                         new = &parent->rb.rb_right;
 143                         leftmost = false;
 144                 }
 145         }
 146
 147         node->augmented = val;
 148         rb_link_node(&node->rb, rb_parent, new);
 149         rb_insert_augmented_cached(&node->rb, root,
 150                                    leftmost, &augment_callbacks);
 151 }
 152
 153
 154 static void erase_augmented(struct test_node *node, struct rb_root_cached *root)
 155 {
 156         rb_erase_augmented(&node->rb, &root->rb_root, &augment_callbacks);
 157 }
 158
 159 static void erase_augmented_cached(struct test_node *node,
 160                                    struct rb_root_cached *root)
 161 {
 162         rb_erase_augmented_cached(&node->rb, root, &augment_callbacks);
 163 }
 164
 165 static void init(void)
 166 {
 167         int i;
 168         for (i = 0; i < nnodes; i++) {
 169                 nodes[i].key = prandom_u32_state(&rnd);
 170                 nodes[i].val = prandom_u32_state(&rnd);
 171         }
 172 }
 173
 174 static bool is_red(struct rb_node *rb)
 175 {
 176         return !(rb->__rb_parent_color & 1);
 177 }
 178
 179 static int black_path_count(struct rb_node *rb)
 180 {
 181         int count;
 182         for (count = 0; rb; rb = rb_parent(rb))
 183                 count += !is_red(rb);
 184         return count;
 185 }
 186
 187 static void check_postorder_foreach(int nr_nodes)
 188 {
 189         struct test_node *cur, *n;
 190         int count = 0;
 191         rbtree_postorder_for_each_entry_safe(cur, n, &root.rb_root, rb)
 192                 count++;
 193
 194         WARN_ON_ONCE(count != nr_nodes);
 195 }
 196
 197 static void check_postorder(int nr_nodes)
 198 {
 199         struct rb_node *rb;
 200         int count = 0;
 201         for (rb = rb_first_postorder(&root.rb_root); rb; rb = rb_next_postorder(rb))
 202                 count++;
 203
 204         WARN_ON_ONCE(count != nr_nodes);
 205 }
 206
 207 static void check(int nr_nodes)
 208 {
 209         struct rb_node *rb;
 210         int count = 0, blacks = 0;
 211         u32 prev_key = 0;
 212
 213         for (rb = rb_first(&root.rb_root); rb; rb = rb_next(rb)) {
 214                 struct test_node *node = rb_entry(rb, struct test_node, rb);
 215                 WARN_ON_ONCE(node->key < prev_key);
 216                 WARN_ON_ONCE(is_red(rb) &&
 217                              (!rb_parent(rb) || is_red(rb_parent(rb))));
 218                 if (!count)
 219                         blacks = black_path_count(rb);
 220                 else
 221                         WARN_ON_ONCE((!rb->rb_left || !rb->rb_right) &&
 222                                      blacks != black_path_count(rb));
 223                 prev_key = node->key;
 224                 count++;
 225         }
 226
 227         WARN_ON_ONCE(count != nr_nodes);
 228         WARN_ON_ONCE(count < (1 << black_path_count(rb_last(&root.rb_root))) - 1);
 229
 230         check_postorder(nr_nodes);
 231         check_postorder_foreach(nr_nodes);
 232 }
 233
 234 static void check_augmented(int nr_nodes)
 235 {
 236         struct rb_node *rb;
 237
 238         check(nr_nodes);
 239         for (rb = rb_first(&root.rb_root); rb; rb = rb_next(rb)) {
 240                 struct test_node *node = rb_entry(rb, struct test_node, rb);
 241                 WARN_ON_ONCE(node->augmented != augment_recompute(node));
 242         }
 243 }
 244
 245 static int __init rbtree_test_init(void)
 246 {
 247         int i, j;
 248         cycles_t time1, time2, time;
 249         struct rb_node *node;
 250
 251         nodes = kmalloc_array(nnodes, sizeof(*nodes), GFP_KERNEL);
 252         if (!nodes)
 253                 return -ENOMEM;
 254
 255         printk(KERN_ALERT "rbtree testing");
 256
 257         prandom_seed_state(&rnd, 3141592653589793238ULL);
 258         init();
 259
 260         time1 = get_cycles();
 261
 262         for (i = 0; i < perf_loops; i++) {
 263                 for (j = 0; j < nnodes; j++)
 264                         insert(nodes + j, &root);
 265                 for (j = 0; j < nnodes; j++)
 266                         erase(nodes + j, &root);
 267         }
 268
 269         time2 = get_cycles();
 270         time = time2 - time1;
 271
 272         time = div_u64(time, perf_loops);
 273         printk(" -> test 1 (latency of nnodes insert+delete): %llu cycles\n",
 274                (unsigned long long)time);
 275
 276         time1 = get_cycles();
 277
 278         for (i = 0; i < perf_loops; i++) {
 279                 for (j = 0; j < nnodes; j++)
 280                         insert_cached(nodes + j, &root);
 281                 for (j = 0; j < nnodes; j++)
 282                         erase_cached(nodes + j, &root);
 283         }
 284
 285         time2 = get_cycles();
 286         time = time2 - time1;
 287
 288         time = div_u64(time, perf_loops);
 289         printk(" -> test 2 (latency of nnodes cached insert+delete): %llu cycles\n",
 290                (unsigned long long)time);
 291
 292         for (i = 0; i < nnodes; i++)
 293                 insert(nodes + i, &root);
 294
 295         time1 = get_cycles();
 296
 297         for (i = 0; i < perf_loops; i++) {
 298                 for (node = rb_first(&root.rb_root); node; node = rb_next(node))
 299                         ;
 300         }
 301
 302         time2 = get_cycles();
 303         time = time2 - time1;
 304
 305         time = div_u64(time, perf_loops);
 306         printk(" -> test 3 (latency of inorder traversal): %llu cycles\n",
 307                (unsigned long long)time);
 308
 309         time1 = get_cycles();
 310
 311         for (i = 0; i < perf_loops; i++)
 312                 node = rb_first(&root.rb_root);
 313
 314         time2 = get_cycles();
 315         time = time2 - time1;
 316
 317         time = div_u64(time, perf_loops);
 318         printk(" -> test 4 (latency to fetch first node)\n");
 319         printk("        non-cached: %llu cycles\n", (unsigned long long)time);
 320
 321         time1 = get_cycles();
 322
 323         for (i = 0; i < perf_loops; i++)
 324                 node = rb_first_cached(&root);
 325
 326         time2 = get_cycles();
 327         time = time2 - time1;
 328
 329         time = div_u64(time, perf_loops);
 330         printk("        cached: %llu cycles\n", (unsigned long long)time);
 331
 332         for (i = 0; i < nnodes; i++)
 333                 erase(nodes + i, &root);
 334
 335         /* run checks */
 336         for (i = 0; i < check_loops; i++) {
 337                 init();
 338                 for (j = 0; j < nnodes; j++) {
 339                         check(j);
 340                         insert(nodes + j, &root);
 341                 }
 342                 for (j = 0; j < nnodes; j++) {
 343                         check(nnodes - j);
 344                         erase(nodes + j, &root);
 345                 }
 346                 check(0);
 347         }
 348
 349         printk(KERN_ALERT "augmented rbtree testing");
 350
 351         init();
 352
 353         time1 = get_cycles();
 354
 355         for (i = 0; i < perf_loops; i++) {
 356                 for (j = 0; j < nnodes; j++)
 357                         insert_augmented(nodes + j, &root);
 358                 for (j = 0; j < nnodes; j++)
 359                         erase_augmented(nodes + j, &root);
 360         }
 361
 362         time2 = get_cycles();
 363         time = time2 - time1;
 364
 365         time = div_u64(time, perf_loops);
 366         printk(" -> test 1 (latency of nnodes insert+delete): %llu cycles\n", (unsigned long long)time);
 367
 368         time1 = get_cycles();
 369
 370         for (i = 0; i < perf_loops; i++) {
 371                 for (j = 0; j < nnodes; j++)
 372                         insert_augmented_cached(nodes + j, &root);
 373                 for (j = 0; j < nnodes; j++)
 374                         erase_augmented_cached(nodes + j, &root);
 375         }
 376
 377         time2 = get_cycles();
 378         time = time2 - time1;
 379
 380         time = div_u64(time, perf_loops);
 381         printk(" -> test 2 (latency of nnodes cached insert+delete): %llu cycles\n", (unsigned long long)time);
 382
 383         for (i = 0; i < check_loops; i++) {
 384                 init();
 385                 for (j = 0; j < nnodes; j++) {
 386                         check_augmented(j);
 387                         insert_augmented(nodes + j, &root);
 388                 }
 389                 for (j = 0; j < nnodes; j++) {
 390                         check_augmented(nnodes - j);
 391                         erase_augmented(nodes + j, &root);
 392                 }
 393                 check_augmented(0);
 394         }
 395
 396         kfree(nodes);
 397
 398         return -EAGAIN; /* Fail will directly unload the module */
 399 }
 400
 401 static void __exit rbtree_test_exit(void)
 402 {
 403         printk(KERN_ALERT "test exit\n");
 404 }
 405
 406 module_init(rbtree_test_init)
 407 module_exit(rbtree_test_exit)
 408
 409 MODULE_LICENSE("GPL");
 410 MODULE_AUTHOR("Michel Lespinasse");
 411 MODULE_DESCRIPTION("Red Black Tree test");