linux/lib/interval_tree_test.c
Davidlohr Bueso f808c13fd3 lib/interval_tree: fast overlap detection
Allow interval trees to quickly check for overlaps to avoid unnecesary
tree lookups in interval_tree_iter_first().

As of this patch, all interval tree flavors will require using a
'rb_root_cached' such that we can have the leftmost node easily
available.  While most users will make use of this feature, those with
special functions (in addition to the generic insert, delete, search
calls) will avoid using the cached option as they can do funky things
with insertions -- for example, vma_interval_tree_insert_after().

[jglisse@redhat.com: fix deadlock from typo vm_lock_anon_vma()]
  Link: http://lkml.kernel.org/r/20170808225719.20723-1-jglisse@redhat.com
Link: http://lkml.kernel.org/r/20170719014603.19029-12-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Doug Ledford <dledford@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Christian Benvenuti <benve@cisco.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-08 18:26:49 -07:00

138 lines
3.4 KiB
C

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/interval_tree.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <asm/timex.h>
#define __param(type, name, init, msg) \
static type name = init; \
module_param(name, type, 0444); \
MODULE_PARM_DESC(name, msg);
__param(int, nnodes, 100, "Number of nodes in the interval tree");
__param(int, perf_loops, 100000, "Number of iterations modifying the tree");
__param(int, nsearches, 100, "Number of searches to the interval tree");
__param(int, search_loops, 10000, "Number of iterations searching the tree");
__param(bool, search_all, false, "Searches will iterate all nodes in the tree");
__param(uint, max_endpoint, ~0, "Largest value for the interval's endpoint");
static struct rb_root_cached root = RB_ROOT_CACHED;
static struct interval_tree_node *nodes = NULL;
static u32 *queries = NULL;
static struct rnd_state rnd;
static inline unsigned long
search(struct rb_root_cached *root, unsigned long start, unsigned long last)
{
struct interval_tree_node *node;
unsigned long results = 0;
for (node = interval_tree_iter_first(root, start, last); node;
node = interval_tree_iter_next(node, start, last))
results++;
return results;
}
static void init(void)
{
int i;
for (i = 0; i < nnodes; i++) {
u32 b = (prandom_u32_state(&rnd) >> 4) % max_endpoint;
u32 a = (prandom_u32_state(&rnd) >> 4) % b;
nodes[i].start = a;
nodes[i].last = b;
}
/*
* Limit the search scope to what the user defined.
* Otherwise we are merely measuring empty walks,
* which is pointless.
*/
for (i = 0; i < nsearches; i++)
queries[i] = (prandom_u32_state(&rnd) >> 4) % max_endpoint;
}
static int interval_tree_test_init(void)
{
int i, j;
unsigned long results;
cycles_t time1, time2, time;
nodes = kmalloc(nnodes * sizeof(struct interval_tree_node), GFP_KERNEL);
if (!nodes)
return -ENOMEM;
queries = kmalloc(nsearches * sizeof(int), GFP_KERNEL);
if (!queries) {
kfree(nodes);
return -ENOMEM;
}
printk(KERN_ALERT "interval tree insert/remove");
prandom_seed_state(&rnd, 3141592653589793238ULL);
init();
time1 = get_cycles();
for (i = 0; i < perf_loops; i++) {
for (j = 0; j < nnodes; j++)
interval_tree_insert(nodes + j, &root);
for (j = 0; j < nnodes; j++)
interval_tree_remove(nodes + j, &root);
}
time2 = get_cycles();
time = time2 - time1;
time = div_u64(time, perf_loops);
printk(" -> %llu cycles\n", (unsigned long long)time);
printk(KERN_ALERT "interval tree search");
for (j = 0; j < nnodes; j++)
interval_tree_insert(nodes + j, &root);
time1 = get_cycles();
results = 0;
for (i = 0; i < search_loops; i++)
for (j = 0; j < nsearches; j++) {
unsigned long start = search_all ? 0 : queries[j];
unsigned long last = search_all ? max_endpoint : queries[j];
results += search(&root, start, last);
}
time2 = get_cycles();
time = time2 - time1;
time = div_u64(time, search_loops);
results = div_u64(results, search_loops);
printk(" -> %llu cycles (%lu results)\n",
(unsigned long long)time, results);
kfree(queries);
kfree(nodes);
return -EAGAIN; /* Fail will directly unload the module */
}
static void interval_tree_test_exit(void)
{
printk(KERN_ALERT "test exit\n");
}
module_init(interval_tree_test_init)
module_exit(interval_tree_test_exit)
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Michel Lespinasse");
MODULE_DESCRIPTION("Interval Tree test");