xref: /openbmc/linux/lib/rbtree_test.c (revision c4f7ac64)
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");
409