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rbtree: augmented rbtree test 

Small test to measure the performance of augmented rbtrees.

Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: Rik 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Michel Lespinasse 2012-10-08 16:31:15 -07:00 committed by Linus Torvalds
parent 4f035ad67f
commit dadf93534f
1 changed files with 101 additions and 2 deletions
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103
lib/rbtree_test.c
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@ -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 */
}