lib/rbtree_test.c

   1 #include <linux/module.h>
   2 #include <linux/moduleparam.h>
   3 #include <linux/rbtree_augmented.h>
   4 #include <linux/random.h>
   5 #include <linux/slab.h>
   6 #include <asm/timex.h>
   7
   8 #define __param(type, name, init, msg)          \
   9         static type name = init;                \
  10         module_param(name, type, 0444);         \
  11         MODULE_PARM_DESC(name, msg);
  12
  13 __param(int, nnodes, 100, "Number of nodes in the rb-tree");
  14 __param(int, perf_loops, 100000, "Number of iterations modifying the rb-tree");
  15 __param(int, check_loops, 100, "Number of iterations modifying and verifying the rb-tree");
  16
  17 struct test_node {
  18         u32 key;
  19         struct rb_node rb;
  20
  21         /* following fields used for testing augmented rbtree functionality */
  22         u32 val;
  23         u32 augmented;
  24 };
  25
  26 static struct rb_root_cached root = RB_ROOT_CACHED;
  27 static struct test_node *nodes = NULL;
  28
  29 static struct rnd_state rnd;
  30
  31 static void insert(struct test_node *node, struct rb_root_cached *root)
  32 {
  33         struct rb_node **new = &root->rb_root.rb_node, *parent = NULL;
  34         u32 key = node->key;
  35
  36         while (*new) {
  37                 parent = *new;
  38                 if (key < rb_entry(parent, struct test_node, rb)->key)
  39                         new = &parent->rb_left;
  40                 else
  41                         new = &parent->rb_right;
  42         }
  43
  44         rb_link_node(&node->rb, parent, new);
  45         rb_insert_color(&node->rb, &root->rb_root);
  46 }
  47
  48 static void insert_cached(struct test_node *node, struct rb_root_cached *root)
  49 {
  50         struct rb_node **new = &root->rb_root.rb_node, *parent = NULL;
  51         u32 key = node->key;
  52         bool leftmost = true;
  53
  54         while (*new) {
  55                 parent = *new;
  56                 if (key < rb_entry(parent, struct test_node, rb)->key)
  57                         new = &parent->rb_left;
  58                 else {
  59                         new = &parent->rb_right;
  60                         leftmost = false;
  61                 }
  62         }
  63
  64         rb_link_node(&node->rb, parent, new);
  65         rb_insert_color_cached(&node->rb, root, leftmost);
  66 }
  67
  68 static inline void erase(struct test_node *node, struct rb_root_cached *root)
  69 {
  70         rb_erase(&node->rb, &root->rb_root);
  71 }
  72
  73 static inline void erase_cached(struct test_node *node, struct rb_root_cached *root)
  74 {
  75         rb_erase_cached(&node->rb, root);
  76 }
  77
  78
  79 static inline u32 augment_recompute(struct test_node *node)
  80 {
  81         u32 max = node->val, child_augmented;
  82         if (node->rb.rb_left) {
  83                 child_augmented = rb_entry(node->rb.rb_left, struct test_node,
  84                                            rb)->augmented;
  85                 if (max < child_augmented)
  86                         max = child_augmented;
  87         }
  88         if (node->rb.rb_right) {
  89                 child_augmented = rb_entry(node->rb.rb_right, struct test_node,
  90                                            rb)->augmented;
  91                 if (max < child_augmented)
  92                         max = child_augmented;
  93         }
  94         return max;
  95 }
  96
  97 RB_DECLARE_CALLBACKS(static, augment_callbacks, struct test_node, rb,
  98                      u32, augmented, augment_recompute)
  99
 100 static void insert_augmented(struct test_node *node,
 101                              struct rb_root_cached *root)
 102 {
 103         struct rb_node **new = &root->rb_root.rb_node, *rb_parent = NULL;
 104         u32 key = node->key;
 105         u32 val = node->val;
 106         struct test_node *parent;
 107
 108         while (*new) {
 109                 rb_parent = *new;
 110                 parent = rb_entry(rb_parent, struct test_node, rb);
 111                 if (parent->augmented < val)
 112                         parent->augmented = val;
 113                 if (key < parent->key)
 114                         new = &parent->rb.rb_left;
 115                 else
 116                         new = &parent->rb.rb_right;
 117         }
 118
 119         node->augmented = val;
 120         rb_link_node(&node->rb, rb_parent, new);
 121         rb_insert_augmented(&node->rb, &root->rb_root, &augment_callbacks);
 122 }
 123
 124 static void insert_augmented_cached(struct test_node *node,
 125                                     struct rb_root_cached *root)
 126 {
 127         struct rb_node **new = &root->rb_root.rb_node, *rb_parent = NULL;
 128         u32 key = node->key;
 129         u32 val = node->val;
 130         struct test_node *parent;
 131         bool leftmost = true;
 132
 133         while (*new) {
 134                 rb_parent = *new;
 135                 parent = rb_entry(rb_parent, struct test_node, rb);
 136                 if (parent->augmented < val)
 137                         parent->augmented = val;
 138                 if (key < parent->key)
 139                         new = &parent->rb.rb_left;
 140                 else {
 141                         new = &parent->rb.rb_right;
 142                         leftmost = false;
 143                 }
 144         }
 145
 146         node->augmented = val;
 147         rb_link_node(&node->rb, rb_parent, new);
 148         rb_insert_augmented_cached(&node->rb, root,
 149                                    leftmost, &augment_callbacks);
 150 }
 151
 152
 153 static void erase_augmented(struct test_node *node, struct rb_root_cached *root)
 154 {
 155         rb_erase_augmented(&node->rb, &root->rb_root, &augment_callbacks);
 156 }
 157
 158 static void erase_augmented_cached(struct test_node *node,
 159                                    struct rb_root_cached *root)
 160 {
 161         rb_erase_augmented_cached(&node->rb, root, &augment_callbacks);
 162 }
 163
 164 static void init(void)
 165 {
 166         int i;
 167         for (i = 0; i < nnodes; i++) {
 168                 nodes[i].key = prandom_u32_state(&rnd);
 169                 nodes[i].val = prandom_u32_state(&rnd);
 170         }
 171 }
 172
 173 static bool is_red(struct rb_node *rb)
 174 {
 175         return !(rb->__rb_parent_color & 1);
 176 }
 177
 178 static int black_path_count(struct rb_node *rb)
 179 {
 180         int count;
 181         for (count = 0; rb; rb = rb_parent(rb))
 182                 count += !is_red(rb);
 183         return count;
 184 }
 185
 186 static void check_postorder_foreach(int nr_nodes)
 187 {
 188         struct test_node *cur, *n;
 189         int count = 0;
 190         rbtree_postorder_for_each_entry_safe(cur, n, &root.rb_root, rb)
 191                 count++;
 192
 193         WARN_ON_ONCE(count != nr_nodes);
 194 }
 195
 196 static void check_postorder(int nr_nodes)
 197 {
 198         struct rb_node *rb;
 199         int count = 0;
 200         for (rb = rb_first_postorder(&root.rb_root); rb; rb = rb_next_postorder(rb))
 201                 count++;
 202
 203         WARN_ON_ONCE(count != nr_nodes);
 204 }
 205
 206 static void check(int nr_nodes)
 207 {
 208         struct rb_node *rb;
 209         int count = 0, blacks = 0;
 210         u32 prev_key = 0;
 211
 212         for (rb = rb_first(&root.rb_root); rb; rb = rb_next(rb)) {
 213                 struct test_node *node = rb_entry(rb, struct test_node, rb);
 214                 WARN_ON_ONCE(node->key < prev_key);
 215                 WARN_ON_ONCE(is_red(rb) &&
 216                              (!rb_parent(rb) || is_red(rb_parent(rb))));
 217                 if (!count)
 218                         blacks = black_path_count(rb);
 219                 else
 220                         WARN_ON_ONCE((!rb->rb_left || !rb->rb_right) &&
 221                                      blacks != black_path_count(rb));
 222                 prev_key = node->key;
 223                 count++;
 224         }
 225
 226         WARN_ON_ONCE(count != nr_nodes);
 227         WARN_ON_ONCE(count < (1 << black_path_count(rb_last(&root.rb_root))) - 1);
 228
 229         check_postorder(nr_nodes);
 230         check_postorder_foreach(nr_nodes);
 231 }
 232
 233 static void check_augmented(int nr_nodes)
 234 {
 235         struct rb_node *rb;
 236
 237         check(nr_nodes);
 238         for (rb = rb_first(&root.rb_root); rb; rb = rb_next(rb)) {
 239                 struct test_node *node = rb_entry(rb, struct test_node, rb);
 240                 WARN_ON_ONCE(node->augmented != augment_recompute(node));
 241         }
 242 }
 243
 244 static int __init rbtree_test_init(void)
 245 {
 246         int i, j;
 247         cycles_t time1, time2, time;
 248         struct rb_node *node;
 249
 250         nodes = kmalloc(nnodes * sizeof(*nodes), GFP_KERNEL);
 251         if (!nodes)
 252                 return -ENOMEM;
 253
 254         printk(KERN_ALERT "rbtree testing");
 255
 256         prandom_seed_state(&rnd, 3141592653589793238ULL);
 257         init();
 258
 259         time1 = get_cycles();
 260
 261         for (i = 0; i < perf_loops; i++) {
 262                 for (j = 0; j < nnodes; j++)
 263                         insert(nodes + j, &root);
 264                 for (j = 0; j < nnodes; j++)
 265                         erase(nodes + j, &root);
 266         }
 267
 268         time2 = get_cycles();
 269         time = time2 - time1;
 270
 271         time = div_u64(time, perf_loops);
 272         printk(" -> test 1 (latency of nnodes insert+delete): %llu cycles\n",
 273                (unsigned long long)time);
 274
 275         time1 = get_cycles();
 276
 277         for (i = 0; i < perf_loops; i++) {
 278                 for (j = 0; j < nnodes; j++)
 279                         insert_cached(nodes + j, &root);
 280                 for (j = 0; j < nnodes; j++)
 281                         erase_cached(nodes + j, &root);
 282         }
 283
 284         time2 = get_cycles();
 285         time = time2 - time1;
 286
 287         time = div_u64(time, perf_loops);
 288         printk(" -> test 2 (latency of nnodes cached insert+delete): %llu cycles\n",
 289                (unsigned long long)time);
 290
 291         for (i = 0; i < nnodes; i++)
 292                 insert(nodes + i, &root);
 293
 294         time1 = get_cycles();
 295
 296         for (i = 0; i < perf_loops; i++) {
 297                 for (node = rb_first(&root.rb_root); node; node = rb_next(node))
 298                         ;
 299         }
 300
 301         time2 = get_cycles();
 302         time = time2 - time1;
 303
 304         time = div_u64(time, perf_loops);
 305         printk(" -> test 3 (latency of inorder traversal): %llu cycles\n",
 306                (unsigned long long)time);
 307
 308         time1 = get_cycles();
 309
 310         for (i = 0; i < perf_loops; i++)
 311                 node = rb_first(&root.rb_root);
 312
 313         time2 = get_cycles();
 314         time = time2 - time1;
 315
 316         time = div_u64(time, perf_loops);
 317         printk(" -> test 4 (latency to fetch first node)\n");
 318         printk("        non-cached: %llu cycles\n", (unsigned long long)time);
 319
 320         time1 = get_cycles();
 321
 322         for (i = 0; i < perf_loops; i++)
 323                 node = rb_first_cached(&root);
 324
 325         time2 = get_cycles();
 326         time = time2 - time1;
 327
 328         time = div_u64(time, perf_loops);
 329         printk("        cached: %llu cycles\n", (unsigned long long)time);
 330
 331         for (i = 0; i < nnodes; i++)
 332                 erase(nodes + i, &root);
 333
 334         /* run checks */
 335         for (i = 0; i < check_loops; i++) {
 336                 init();
 337                 for (j = 0; j < nnodes; j++) {
 338                         check(j);
 339                         insert(nodes + j, &root);
 340                 }
 341                 for (j = 0; j < nnodes; j++) {
 342                         check(nnodes - j);
 343                         erase(nodes + j, &root);
 344                 }
 345                 check(0);
 346         }
 347
 348         printk(KERN_ALERT "augmented rbtree testing");
 349
 350         init();
 351
 352         time1 = get_cycles();
 353
 354         for (i = 0; i < perf_loops; i++) {
 355                 for (j = 0; j < nnodes; j++)
 356                         insert_augmented(nodes + j, &root);
 357                 for (j = 0; j < nnodes; j++)
 358                         erase_augmented(nodes + j, &root);
 359         }
 360
 361         time2 = get_cycles();
 362         time = time2 - time1;
 363
 364         time = div_u64(time, perf_loops);
 365         printk(" -> test 1 (latency of nnodes insert+delete): %llu cycles\n", (unsigned long long)time);
 366
 367         time1 = get_cycles();
 368
 369         for (i = 0; i < perf_loops; i++) {
 370                 for (j = 0; j < nnodes; j++)
 371                         insert_augmented_cached(nodes + j, &root);
 372                 for (j = 0; j < nnodes; j++)
 373                         erase_augmented_cached(nodes + j, &root);
 374         }
 375
 376         time2 = get_cycles();
 377         time = time2 - time1;
 378
 379         time = div_u64(time, perf_loops);
 380         printk(" -> test 2 (latency of nnodes cached insert+delete): %llu cycles\n", (unsigned long long)time);
 381
 382         for (i = 0; i < check_loops; i++) {
 383                 init();
 384                 for (j = 0; j < nnodes; j++) {
 385                         check_augmented(j);
 386                         insert_augmented(nodes + j, &root);
 387                 }
 388                 for (j = 0; j < nnodes; j++) {
 389                         check_augmented(nnodes - j);
 390                         erase_augmented(nodes + j, &root);
 391                 }
 392                 check_augmented(0);
 393         }
 394
 395         kfree(nodes);
 396
 397         return -EAGAIN; /* Fail will directly unload the module */
 398 }
 399
 400 static void __exit rbtree_test_exit(void)
 401 {
 402         printk(KERN_ALERT "test exit\n");
 403 }
 404
 405 module_init(rbtree_test_init)
 406 module_exit(rbtree_test_exit)
 407
 408 MODULE_LICENSE("GPL");
 409 MODULE_AUTHOR("Michel Lespinasse");
 410 MODULE_DESCRIPTION("Red Black Tree test");