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Commit dadf9353 authored by Michel Lespinasse's avatar Michel Lespinasse Committed by Linus Torvalds
Browse files

rbtree: augmented rbtree test 



Small test to measure the performance of augmented rbtrees.

Signed-off-by: default avatarMichel Lespinasse <walken@google.com>
Acked-by: default avatarRik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4f035ad6

lib/rbtree_test.c

+101 −2
Original line number Diff line number Diff line
@@ -10,6 +10,10 @@ 
struct test_node {

	struct rb_node rb;

	u32 key;



	/* following fields used for testing augmented rbtree functionality */

	u32 val;

	u32 augmented;

};



static struct rb_root root = RB_ROOT;
@@ -20,10 +24,11 @@ static struct rnd_state rnd; 
static void insert(struct test_node *node, struct rb_root *root)

{

	struct rb_node **new = &root->rb_node, *parent = NULL;

	u32 key = node->key;



	while (*new) {

		parent = *new;

		if (node->key < rb_entry(parent, struct test_node, rb)->key)

		if (key < rb_entry(parent, struct test_node, rb)->key)

			new = &parent->rb_left;

		else

			new = &parent->rb_right;
@@ -38,11 +43,62 @@ static inline void erase(struct test_node *node, struct rb_root *root) 
	rb_erase(&node->rb, root);

}



static inline u32 augment_recompute(struct test_node *node)

{

	u32 max = node->val, child_augmented;

	if (node->rb.rb_left) {

		child_augmented = rb_entry(node->rb.rb_left, struct test_node,

					   rb)->augmented;

		if (max < child_augmented)

			max = child_augmented;

	}

	if (node->rb.rb_right) {

		child_augmented = rb_entry(node->rb.rb_right, struct test_node,

					   rb)->augmented;

		if (max < child_augmented)

			max = child_augmented;

	}

	return max;

}



static void augment_callback(struct rb_node *rb, void *unused)

{

	struct test_node *node = rb_entry(rb, struct test_node, rb);

	node->augmented = augment_recompute(node);

}



static void insert_augmented(struct test_node *node, struct rb_root *root)

{

	struct rb_node **new = &root->rb_node, *parent = NULL;

	u32 key = node->key;



	while (*new) {

		parent = *new;

		if (key < rb_entry(parent, struct test_node, rb)->key)

			new = &parent->rb_left;

		else

			new = &parent->rb_right;

	}



	rb_link_node(&node->rb, parent, new);

	rb_insert_color(&node->rb, root);

	rb_augment_insert(&node->rb, augment_callback, NULL);

}



static void erase_augmented(struct test_node *node, struct rb_root *root)

{

	struct rb_node *deepest = rb_augment_erase_begin(&node->rb);

	rb_erase(&node->rb, root);

	rb_augment_erase_end(deepest, augment_callback, NULL);

}



static void init(void)

{

	int i;

	for (i = 0; i < NODES; i++)

	for (i = 0; i < NODES; i++) {

		nodes[i].key = prandom32(&rnd);

		nodes[i].val = prandom32(&rnd);

	}

}



static bool is_red(struct rb_node *rb)
@@ -81,6 +137,17 @@ static void check(int nr_nodes) 
	WARN_ON_ONCE(count != nr_nodes);

}



static void check_augmented(int nr_nodes)

{

	struct rb_node *rb;



	check(nr_nodes);

	for (rb = rb_first(&root); rb; rb = rb_next(rb)) {

		struct test_node *node = rb_entry(rb, struct test_node, rb);

		WARN_ON_ONCE(node->augmented != augment_recompute(node));

	}

}



static int rbtree_test_init(void)

{

	int i, j;
@@ -119,6 +186,38 @@ static int rbtree_test_init(void) 
		check(0);

	}



	printk(KERN_ALERT "augmented rbtree testing");



	init();



	time1 = get_cycles();



	for (i = 0; i < PERF_LOOPS; i++) {

		for (j = 0; j < NODES; j++)

			insert_augmented(nodes + j, &root);

		for (j = 0; j < NODES; j++)

			erase_augmented(nodes + j, &root);

	}



	time2 = get_cycles();

	time = time2 - time1;



	time = div_u64(time, PERF_LOOPS);

	printk(" -> %llu cycles\n", (unsigned long long)time);



	for (i = 0; i < CHECK_LOOPS; i++) {

		init();

		for (j = 0; j < NODES; j++) {

			check_augmented(j);

			insert_augmented(nodes + j, &root);

		}

		for (j = 0; j < NODES; j++) {

			check_augmented(NODES - j);

			erase_augmented(nodes + j, &root);

		}

		check_augmented(0);

	}



	return -EAGAIN; /* Fail will directly unload the module */

}