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/prandom.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__param(ullong, seed, 3141592653589793238ULL, "Random seed");
 18
 19struct test_node {
 20	u32 key;
 21	struct rb_node rb;
 22
 23	/* following fields used for testing augmented rbtree functionality */
 24	u32 val;
 25	u32 augmented;
 26};
 27
 28static struct rb_root_cached root = RB_ROOT_CACHED;
 29static struct test_node *nodes = NULL;
 30
 31static struct rnd_state rnd;
 32
 33static void insert(struct test_node *node, struct rb_root_cached *root)
 34{
 35	struct rb_node **new = &root->rb_root.rb_node, *parent = NULL;
 36	u32 key = node->key;
 37
 38	while (*new) {
 39		parent = *new;
 40		if (key < rb_entry(parent, struct test_node, rb)->key)
 41			new = &parent->rb_left;
 42		else
 43			new = &parent->rb_right;
 44	}
 45
 46	rb_link_node(&node->rb, parent, new);
 47	rb_insert_color(&node->rb, &root->rb_root);
 48}
 49
 50static void insert_cached(struct test_node *node, struct rb_root_cached *root)
 51{
 52	struct rb_node **new = &root->rb_root.rb_node, *parent = NULL;
 53	u32 key = node->key;
 54	bool leftmost = true;
 55
 56	while (*new) {
 57		parent = *new;
 58		if (key < rb_entry(parent, struct test_node, rb)->key)
 59			new = &parent->rb_left;
 60		else {
 61			new = &parent->rb_right;
 62			leftmost = false;
 63		}
 64	}
 65
 66	rb_link_node(&node->rb, parent, new);
 67	rb_insert_color_cached(&node->rb, root, leftmost);
 68}
 69
 70static inline void erase(struct test_node *node, struct rb_root_cached *root)
 71{
 72	rb_erase(&node->rb, &root->rb_root);
 73}
 74
 75static inline void erase_cached(struct test_node *node, struct rb_root_cached *root)
 76{
 77	rb_erase_cached(&node->rb, root);
 78}
 79
 80
 81#define NODE_VAL(node) ((node)->val)
 82
 83RB_DECLARE_CALLBACKS_MAX(static, augment_callbacks,
 84			 struct test_node, rb, u32, augmented, NODE_VAL)
 85
 86static void insert_augmented(struct test_node *node,
 87			     struct rb_root_cached *root)
 88{
 89	struct rb_node **new = &root->rb_root.rb_node, *rb_parent = NULL;
 90	u32 key = node->key;
 91	u32 val = node->val;
 92	struct test_node *parent;
 93
 94	while (*new) {
 95		rb_parent = *new;
 96		parent = rb_entry(rb_parent, struct test_node, rb);
 97		if (parent->augmented < val)
 98			parent->augmented = val;
 99		if (key < parent->key)
100			new = &parent->rb.rb_left;
101		else
102			new = &parent->rb.rb_right;
103	}
104
105	node->augmented = val;
106	rb_link_node(&node->rb, rb_parent, new);
107	rb_insert_augmented(&node->rb, &root->rb_root, &augment_callbacks);
108}
109
110static void insert_augmented_cached(struct test_node *node,
111				    struct rb_root_cached *root)
112{
113	struct rb_node **new = &root->rb_root.rb_node, *rb_parent = NULL;
114	u32 key = node->key;
115	u32 val = node->val;
116	struct test_node *parent;
117	bool leftmost = true;
118
119	while (*new) {
120		rb_parent = *new;
121		parent = rb_entry(rb_parent, struct test_node, rb);
122		if (parent->augmented < val)
123			parent->augmented = val;
124		if (key < parent->key)
125			new = &parent->rb.rb_left;
126		else {
127			new = &parent->rb.rb_right;
128			leftmost = false;
129		}
130	}
131
132	node->augmented = val;
133	rb_link_node(&node->rb, rb_parent, new);
134	rb_insert_augmented_cached(&node->rb, root,
135				   leftmost, &augment_callbacks);
136}
137
138
139static void erase_augmented(struct test_node *node, struct rb_root_cached *root)
140{
141	rb_erase_augmented(&node->rb, &root->rb_root, &augment_callbacks);
142}
143
144static void erase_augmented_cached(struct test_node *node,
145				   struct rb_root_cached *root)
146{
147	rb_erase_augmented_cached(&node->rb, root, &augment_callbacks);
148}
149
150static void init(void)
151{
152	int i;
153	for (i = 0; i < nnodes; i++) {
154		nodes[i].key = prandom_u32_state(&rnd);
155		nodes[i].val = prandom_u32_state(&rnd);
156	}
157}
158
159static bool is_red(struct rb_node *rb)
160{
161	return !(rb->__rb_parent_color & 1);
162}
163
164static int black_path_count(struct rb_node *rb)
165{
166	int count;
167	for (count = 0; rb; rb = rb_parent(rb))
168		count += !is_red(rb);
169	return count;
170}
171
172static void check_postorder_foreach(int nr_nodes)
173{
174	struct test_node *cur, *n;
175	int count = 0;
176	rbtree_postorder_for_each_entry_safe(cur, n, &root.rb_root, rb)
177		count++;
178
179	WARN_ON_ONCE(count != nr_nodes);
180}
181
182static void check_postorder(int nr_nodes)
183{
184	struct rb_node *rb;
185	int count = 0;
186	for (rb = rb_first_postorder(&root.rb_root); rb; rb = rb_next_postorder(rb))
187		count++;
188
189	WARN_ON_ONCE(count != nr_nodes);
190}
191
192static void check(int nr_nodes)
193{
194	struct rb_node *rb;
195	int count = 0, blacks = 0;
196	u32 prev_key = 0;
197
198	for (rb = rb_first(&root.rb_root); rb; rb = rb_next(rb)) {
199		struct test_node *node = rb_entry(rb, struct test_node, rb);
200		WARN_ON_ONCE(node->key < prev_key);
201		WARN_ON_ONCE(is_red(rb) &&
202			     (!rb_parent(rb) || is_red(rb_parent(rb))));
203		if (!count)
204			blacks = black_path_count(rb);
205		else
206			WARN_ON_ONCE((!rb->rb_left || !rb->rb_right) &&
207				     blacks != black_path_count(rb));
208		prev_key = node->key;
209		count++;
210	}
211
212	WARN_ON_ONCE(count != nr_nodes);
213	WARN_ON_ONCE(count < (1 << black_path_count(rb_last(&root.rb_root))) - 1);
214
215	check_postorder(nr_nodes);
216	check_postorder_foreach(nr_nodes);
217}
218
219static void check_augmented(int nr_nodes)
220{
221	struct rb_node *rb;
222
223	check(nr_nodes);
224	for (rb = rb_first(&root.rb_root); rb; rb = rb_next(rb)) {
225		struct test_node *node = rb_entry(rb, struct test_node, rb);
226		u32 subtree, max = node->val;
227		if (node->rb.rb_left) {
228			subtree = rb_entry(node->rb.rb_left, struct test_node,
229					   rb)->augmented;
230			if (max < subtree)
231				max = subtree;
232		}
233		if (node->rb.rb_right) {
234			subtree = rb_entry(node->rb.rb_right, struct test_node,
235					   rb)->augmented;
236			if (max < subtree)
237				max = subtree;
238		}
239		WARN_ON_ONCE(node->augmented != max);
240	}
241}
242
243static int basic_check(void)
244{
245	int i, j;
246	cycles_t time1, time2, time;
247	struct rb_node *node;
248
249	printk(KERN_ALERT "rbtree testing");
250
251	init();
252
253	time1 = get_cycles();
254
255	for (i = 0; i < perf_loops; i++) {
256		for (j = 0; j < nnodes; j++)
257			insert(nodes + j, &root);
258		for (j = 0; j < nnodes; j++)
259			erase(nodes + j, &root);
260	}
261
262	time2 = get_cycles();
263	time = time2 - time1;
264
265	time = div_u64(time, perf_loops);
266	printk(" -> test 1 (latency of nnodes insert+delete): %llu cycles\n",
267	       (unsigned long long)time);
268
269	time1 = get_cycles();
270
271	for (i = 0; i < perf_loops; i++) {
272		for (j = 0; j < nnodes; j++)
273			insert_cached(nodes + j, &root);
274		for (j = 0; j < nnodes; j++)
275			erase_cached(nodes + j, &root);
276	}
277
278	time2 = get_cycles();
279	time = time2 - time1;
280
281	time = div_u64(time, perf_loops);
282	printk(" -> test 2 (latency of nnodes cached insert+delete): %llu cycles\n",
283	       (unsigned long long)time);
284
285	for (i = 0; i < nnodes; i++)
286		insert(nodes + i, &root);
287
288	time1 = get_cycles();
289
290	for (i = 0; i < perf_loops; i++) {
291		for (node = rb_first(&root.rb_root); node; node = rb_next(node))
292			;
293	}
294
295	time2 = get_cycles();
296	time = time2 - time1;
297
298	time = div_u64(time, perf_loops);
299	printk(" -> test 3 (latency of inorder traversal): %llu cycles\n",
300	       (unsigned long long)time);
301
302	time1 = get_cycles();
303
304	for (i = 0; i < perf_loops; i++)
305		node = rb_first(&root.rb_root);
306
307	time2 = get_cycles();
308	time = time2 - time1;
309
310	time = div_u64(time, perf_loops);
311	printk(" -> test 4 (latency to fetch first node)\n");
312	printk("        non-cached: %llu cycles\n", (unsigned long long)time);
313
314	time1 = get_cycles();
315
316	for (i = 0; i < perf_loops; i++)
317		node = rb_first_cached(&root);
318
319	time2 = get_cycles();
320	time = time2 - time1;
321
322	time = div_u64(time, perf_loops);
323	printk("        cached: %llu cycles\n", (unsigned long long)time);
324
325	for (i = 0; i < nnodes; i++)
326		erase(nodes + i, &root);
327
328	/* run checks */
329	for (i = 0; i < check_loops; i++) {
330		init();
331		for (j = 0; j < nnodes; j++) {
332			check(j);
333			insert(nodes + j, &root);
334		}
335		for (j = 0; j < nnodes; j++) {
336			check(nnodes - j);
337			erase(nodes + j, &root);
338		}
339		check(0);
340	}
341
342	return 0;
343}
344
345static int augmented_check(void)
346{
347	int i, j;
348	cycles_t time1, time2, time;
349
350	printk(KERN_ALERT "augmented rbtree testing");
351
352	init();
353
354	time1 = get_cycles();
355
356	for (i = 0; i < perf_loops; i++) {
357		for (j = 0; j < nnodes; j++)
358			insert_augmented(nodes + j, &root);
359		for (j = 0; j < nnodes; j++)
360			erase_augmented(nodes + j, &root);
361	}
362
363	time2 = get_cycles();
364	time = time2 - time1;
365
366	time = div_u64(time, perf_loops);
367	printk(" -> test 1 (latency of nnodes insert+delete): %llu cycles\n", (unsigned long long)time);
368
369	time1 = get_cycles();
370
371	for (i = 0; i < perf_loops; i++) {
372		for (j = 0; j < nnodes; j++)
373			insert_augmented_cached(nodes + j, &root);
374		for (j = 0; j < nnodes; j++)
375			erase_augmented_cached(nodes + j, &root);
376	}
377
378	time2 = get_cycles();
379	time = time2 - time1;
380
381	time = div_u64(time, perf_loops);
382	printk(" -> test 2 (latency of nnodes cached insert+delete): %llu cycles\n", (unsigned long long)time);
383
384	for (i = 0; i < check_loops; i++) {
385		init();
386		for (j = 0; j < nnodes; j++) {
387			check_augmented(j);
388			insert_augmented(nodes + j, &root);
389		}
390		for (j = 0; j < nnodes; j++) {
391			check_augmented(nnodes - j);
392			erase_augmented(nodes + j, &root);
393		}
394		check_augmented(0);
395	}
396
397	return 0;
398}
399
400static int __init rbtree_test_init(void)
401{
402	nodes = kmalloc_array(nnodes, sizeof(*nodes), GFP_KERNEL);
403	if (!nodes)
404		return -ENOMEM;
405
406	prandom_seed_state(&rnd, seed);
407
408	basic_check();
409	augmented_check();
410
411	kfree(nodes);
412
413	return -EAGAIN; /* Fail will directly unload the module */
414}
415
416static void __exit rbtree_test_exit(void)
417{
418	printk(KERN_ALERT "test exit\n");
419}
420
421module_init(rbtree_test_init)
422module_exit(rbtree_test_exit)
423
424MODULE_LICENSE("GPL");
425MODULE_AUTHOR("Michel Lespinasse");
426MODULE_DESCRIPTION("Red Black Tree test");