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lib/rbtree_test.c: support rb_root_cached
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We can work with a single rb_root_cached root to test both cached and
non-cached rbtrees.  In addition, also add a test to measure latencies
between rb_first and its fast counterpart.

Link: http://lkml.kernel.org/r/20170719014603.19029-7-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Davidlohr Bueso authored and Linus Torvalds committed Sep 9, 2017
1 parent 977bd8d commit b10d43f
Showing 1 changed file with 137 additions and 19 deletions.
156 changes: 137 additions & 19 deletions lib/rbtree_test.c
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Original file line number Diff line number Diff line change
Expand Up @@ -23,14 +23,14 @@ struct test_node {
u32 augmented;
};

static struct rb_root root = RB_ROOT;
static struct rb_root_cached root = RB_ROOT_CACHED;
static struct test_node *nodes = NULL;

static struct rnd_state rnd;

static void insert(struct test_node *node, struct rb_root *root)
static void insert(struct test_node *node, struct rb_root_cached *root)
{
struct rb_node **new = &root->rb_node, *parent = NULL;
struct rb_node **new = &root->rb_root.rb_node, *parent = NULL;
u32 key = node->key;

while (*new) {
Expand All @@ -42,14 +42,40 @@ static void insert(struct test_node *node, struct rb_root *root)
}

rb_link_node(&node->rb, parent, new);
rb_insert_color(&node->rb, root);
rb_insert_color(&node->rb, &root->rb_root);
}

static inline void erase(struct test_node *node, struct rb_root *root)
static void insert_cached(struct test_node *node, struct rb_root_cached *root)
{
rb_erase(&node->rb, root);
struct rb_node **new = &root->rb_root.rb_node, *parent = NULL;
u32 key = node->key;
bool leftmost = true;

while (*new) {
parent = *new;
if (key < rb_entry(parent, struct test_node, rb)->key)
new = &parent->rb_left;
else {
new = &parent->rb_right;
leftmost = false;
}
}

rb_link_node(&node->rb, parent, new);
rb_insert_color_cached(&node->rb, root, leftmost);
}

static inline void erase(struct test_node *node, struct rb_root_cached *root)
{
rb_erase(&node->rb, &root->rb_root);
}

static inline void erase_cached(struct test_node *node, struct rb_root_cached *root)
{
rb_erase_cached(&node->rb, root);
}


static inline u32 augment_recompute(struct test_node *node)
{
u32 max = node->val, child_augmented;
Expand All @@ -71,9 +97,10 @@ static inline u32 augment_recompute(struct test_node *node)
RB_DECLARE_CALLBACKS(static, augment_callbacks, struct test_node, rb,
u32, augmented, augment_recompute)

static void insert_augmented(struct test_node *node, struct rb_root *root)
static void insert_augmented(struct test_node *node,
struct rb_root_cached *root)
{
struct rb_node **new = &root->rb_node, *rb_parent = NULL;
struct rb_node **new = &root->rb_root.rb_node, *rb_parent = NULL;
u32 key = node->key;
u32 val = node->val;
struct test_node *parent;
Expand All @@ -91,12 +118,47 @@ static void insert_augmented(struct test_node *node, struct rb_root *root)

node->augmented = val;
rb_link_node(&node->rb, rb_parent, new);
rb_insert_augmented(&node->rb, root, &augment_callbacks);
rb_insert_augmented(&node->rb, &root->rb_root, &augment_callbacks);
}

static void insert_augmented_cached(struct test_node *node,
struct rb_root_cached *root)
{
struct rb_node **new = &root->rb_root.rb_node, *rb_parent = NULL;
u32 key = node->key;
u32 val = node->val;
struct test_node *parent;
bool leftmost = true;

while (*new) {
rb_parent = *new;
parent = rb_entry(rb_parent, struct test_node, rb);
if (parent->augmented < val)
parent->augmented = val;
if (key < parent->key)
new = &parent->rb.rb_left;
else {
new = &parent->rb.rb_right;
leftmost = false;
}
}

node->augmented = val;
rb_link_node(&node->rb, rb_parent, new);
rb_insert_augmented_cached(&node->rb, root,
leftmost, &augment_callbacks);
}


static void erase_augmented(struct test_node *node, struct rb_root_cached *root)
{
rb_erase_augmented(&node->rb, &root->rb_root, &augment_callbacks);
}

static void erase_augmented(struct test_node *node, struct rb_root *root)
static void erase_augmented_cached(struct test_node *node,
struct rb_root_cached *root)
{
rb_erase_augmented(&node->rb, root, &augment_callbacks);
rb_erase_augmented_cached(&node->rb, root, &augment_callbacks);
}

static void init(void)
Expand Down Expand Up @@ -125,7 +187,7 @@ static void check_postorder_foreach(int nr_nodes)
{
struct test_node *cur, *n;
int count = 0;
rbtree_postorder_for_each_entry_safe(cur, n, &root, rb)
rbtree_postorder_for_each_entry_safe(cur, n, &root.rb_root, rb)
count++;

WARN_ON_ONCE(count != nr_nodes);
Expand All @@ -135,7 +197,7 @@ static void check_postorder(int nr_nodes)
{
struct rb_node *rb;
int count = 0;
for (rb = rb_first_postorder(&root); rb; rb = rb_next_postorder(rb))
for (rb = rb_first_postorder(&root.rb_root); rb; rb = rb_next_postorder(rb))
count++;

WARN_ON_ONCE(count != nr_nodes);
Expand All @@ -147,7 +209,7 @@ static void check(int nr_nodes)
int count = 0, blacks = 0;
u32 prev_key = 0;

for (rb = rb_first(&root); rb; rb = rb_next(rb)) {
for (rb = rb_first(&root.rb_root); rb; rb = rb_next(rb)) {
struct test_node *node = rb_entry(rb, struct test_node, rb);
WARN_ON_ONCE(node->key < prev_key);
WARN_ON_ONCE(is_red(rb) &&
Expand All @@ -162,7 +224,7 @@ static void check(int nr_nodes)
}

WARN_ON_ONCE(count != nr_nodes);
WARN_ON_ONCE(count < (1 << black_path_count(rb_last(&root))) - 1);
WARN_ON_ONCE(count < (1 << black_path_count(rb_last(&root.rb_root))) - 1);

check_postorder(nr_nodes);
check_postorder_foreach(nr_nodes);
Expand All @@ -173,7 +235,7 @@ static void check_augmented(int nr_nodes)
struct rb_node *rb;

check(nr_nodes);
for (rb = rb_first(&root); rb; rb = rb_next(rb)) {
for (rb = rb_first(&root.rb_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));
}
Expand Down Expand Up @@ -207,23 +269,64 @@ static int __init rbtree_test_init(void)
time = time2 - time1;

time = div_u64(time, perf_loops);
printk(" -> test 1 (latency of nnodes insert+delete): %llu cycles\n", (unsigned long long)time);
printk(" -> test 1 (latency of nnodes insert+delete): %llu cycles\n",
(unsigned long long)time);

time1 = get_cycles();

for (i = 0; i < perf_loops; i++) {
for (j = 0; j < nnodes; j++)
insert_cached(nodes + j, &root);
for (j = 0; j < nnodes; j++)
erase_cached(nodes + j, &root);
}

time2 = get_cycles();
time = time2 - time1;

time = div_u64(time, perf_loops);
printk(" -> test 2 (latency of nnodes cached insert+delete): %llu cycles\n",
(unsigned long long)time);

for (i = 0; i < nnodes; i++)
insert(nodes + i, &root);

time1 = get_cycles();

for (i = 0; i < perf_loops; i++) {
for (node = rb_first(&root); node; node = rb_next(node))
for (node = rb_first(&root.rb_root); node; node = rb_next(node))
;
}

time2 = get_cycles();
time = time2 - time1;

time = div_u64(time, perf_loops);
printk(" -> test 2 (latency of inorder traversal): %llu cycles\n", (unsigned long long)time);
printk(" -> test 3 (latency of inorder traversal): %llu cycles\n",
(unsigned long long)time);

time1 = get_cycles();

for (i = 0; i < perf_loops; i++)
node = rb_first(&root.rb_root);

time2 = get_cycles();
time = time2 - time1;

time = div_u64(time, perf_loops);
printk(" -> test 4 (latency to fetch first node)\n");
printk(" non-cached: %llu cycles\n", (unsigned long long)time);

time1 = get_cycles();

for (i = 0; i < perf_loops; i++)
node = rb_first_cached(&root);

time2 = get_cycles();
time = time2 - time1;

time = div_u64(time, perf_loops);
printk(" cached: %llu cycles\n", (unsigned long long)time);

for (i = 0; i < nnodes; i++)
erase(nodes + i, &root);
Expand Down Expand Up @@ -261,6 +364,21 @@ static int __init rbtree_test_init(void)
time = div_u64(time, perf_loops);
printk(" -> test 1 (latency of nnodes insert+delete): %llu cycles\n", (unsigned long long)time);

time1 = get_cycles();

for (i = 0; i < perf_loops; i++) {
for (j = 0; j < nnodes; j++)
insert_augmented_cached(nodes + j, &root);
for (j = 0; j < nnodes; j++)
erase_augmented_cached(nodes + j, &root);
}

time2 = get_cycles();
time = time2 - time1;

time = div_u64(time, perf_loops);
printk(" -> test 2 (latency of nnodes cached insert+delete): %llu cycles\n", (unsigned long long)time);

for (i = 0; i < check_loops; i++) {
init();
for (j = 0; j < nnodes; j++) {
Expand Down

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