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>
diff --git a/lib/rbtree_test.c b/lib/rbtree_test.c
index fd09465..66e41d4 100644
--- a/lib/rbtree_test.c
+++ b/lib/rbtree_test.c
@@ -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 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 @@
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 @@
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 @@
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 */
}