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