910a742d4b
This small module helps measure the performance of rbtree insert and erase. Additionally, we run a few correctness tests to check that the rbtrees have all desired properties: - contains the right number of nodes in the order desired, - never two consecutive red nodes on any path, - all paths to leaf nodes have the same number of black nodes, - root node is black [akpm@linux-foundation.org: fix printk warning: sparc64 cycles_t is unsigned long] Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Acked-by: David Woodhouse <David.Woodhouse@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
136 lines
2.6 KiB
C
136 lines
2.6 KiB
C
#include <linux/module.h>
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#include <linux/rbtree.h>
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#include <linux/random.h>
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#include <asm/timex.h>
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#define NODES 100
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#define PERF_LOOPS 100000
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#define CHECK_LOOPS 100
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struct test_node {
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struct rb_node rb;
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u32 key;
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};
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static struct rb_root root = RB_ROOT;
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static struct test_node nodes[NODES];
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static struct rnd_state rnd;
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static void insert(struct test_node *node, struct rb_root *root)
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{
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struct rb_node **new = &root->rb_node, *parent = NULL;
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while (*new) {
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parent = *new;
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if (node->key < rb_entry(parent, struct test_node, rb)->key)
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new = &parent->rb_left;
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else
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new = &parent->rb_right;
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}
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rb_link_node(&node->rb, parent, new);
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rb_insert_color(&node->rb, root);
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}
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static inline void erase(struct test_node *node, struct rb_root *root)
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{
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rb_erase(&node->rb, root);
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}
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static void init(void)
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{
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int i;
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for (i = 0; i < NODES; i++)
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nodes[i].key = prandom32(&rnd);
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}
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static bool is_red(struct rb_node *rb)
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{
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return !(rb->__rb_parent_color & 1);
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}
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static int black_path_count(struct rb_node *rb)
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{
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int count;
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for (count = 0; rb; rb = rb_parent(rb))
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count += !is_red(rb);
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return count;
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}
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static void check(int nr_nodes)
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{
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struct rb_node *rb;
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int count = 0;
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int blacks;
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u32 prev_key = 0;
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for (rb = rb_first(&root); rb; rb = rb_next(rb)) {
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struct test_node *node = rb_entry(rb, struct test_node, rb);
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WARN_ON_ONCE(node->key < prev_key);
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WARN_ON_ONCE(is_red(rb) &&
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(!rb_parent(rb) || is_red(rb_parent(rb))));
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if (!count)
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blacks = black_path_count(rb);
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else
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WARN_ON_ONCE((!rb->rb_left || !rb->rb_right) &&
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blacks != black_path_count(rb));
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prev_key = node->key;
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count++;
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}
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WARN_ON_ONCE(count != nr_nodes);
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}
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static int rbtree_test_init(void)
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{
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int i, j;
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cycles_t time1, time2, time;
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printk(KERN_ALERT "rbtree testing");
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prandom32_seed(&rnd, 3141592653589793238);
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init();
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time1 = get_cycles();
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for (i = 0; i < PERF_LOOPS; i++) {
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for (j = 0; j < NODES; j++)
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insert(nodes + j, &root);
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for (j = 0; j < NODES; j++)
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erase(nodes + j, &root);
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}
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time2 = get_cycles();
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time = time2 - time1;
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time = div_u64(time, PERF_LOOPS);
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printk(" -> %llu cycles\n", (unsigned long long)time);
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for (i = 0; i < CHECK_LOOPS; i++) {
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init();
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for (j = 0; j < NODES; j++) {
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check(j);
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insert(nodes + j, &root);
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}
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for (j = 0; j < NODES; j++) {
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check(NODES - j);
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erase(nodes + j, &root);
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}
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check(0);
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}
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return -EAGAIN; /* Fail will directly unload the module */
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}
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static void rbtree_test_exit(void)
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{
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printk(KERN_ALERT "test exit\n");
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}
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module_init(rbtree_test_init)
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module_exit(rbtree_test_exit)
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Michel Lespinasse");
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MODULE_DESCRIPTION("Red Black Tree test");
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