[ltt-dev] [PATCH 4/6 respin] Avoid alloc small memory pieces
Mathieu Desnoyers
mathieu.desnoyers at efficios.com
Fri Oct 28 02:05:56 EDT 2011
Merged as:
commit 5488222bbdb95680d942c3fb645095b48e96620f
Author: Lai Jiangshan <laijs at cn.fujitsu.com>
Date: Fri Oct 28 08:09:40 2011 +0200
Avoid alloc small memory pieces
Add min_alloc_size (minimum allocation size) for allocation.
Now we can gain better cache locality by specifying larger minimum
allocation size.
Signed-off-by: Lai Jiangshan <laijs at cn.fujitsu.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
diff --git a/rculfhash.c b/rculfhash.c
index 0bcbb1e..675ef38 100644
--- a/rculfhash.c
+++ b/rculfhash.c
@@ -241,6 +241,8 @@ struct cds_lfht {
struct rcu_table t;
cds_lfht_hash_fct hash_fct;
cds_lfht_compare_fct compare_fct;
+ unsigned long min_alloc_order;
+ unsigned long min_alloc_size;
unsigned long hash_seed;
int flags;
/*
@@ -1078,7 +1080,7 @@ void init_table_populate_partition(struct cds_lfht *ht, unsigned long i,
{
unsigned long j;
- assert(i > 0);
+ assert(i > ht->min_alloc_order);
ht->cds_lfht_rcu_read_lock();
for (j = start; j < start + len; j++) {
struct cds_lfht_node *new_node =
@@ -1116,7 +1118,7 @@ void init_table(struct cds_lfht *ht,
dbg_printf("init table: first_order %lu last_order %lu\n",
first_order, last_order);
- assert(first_order > 0);
+ assert(first_order > ht->min_alloc_order);
for (i = first_order; i <= last_order; i++) {
unsigned long len;
@@ -1179,7 +1181,7 @@ void remove_table_partition(struct cds_lfht *ht, unsigned long i,
{
unsigned long j;
- assert(i > 0);
+ assert(i > ht->min_alloc_order);
ht->cds_lfht_rcu_read_lock();
for (j = start; j < start + len; j++) {
struct cds_lfht_node *fini_node =
@@ -1217,7 +1219,7 @@ void fini_table(struct cds_lfht *ht,
dbg_printf("fini table: first_order %lu last_order %lu\n",
first_order, last_order);
- assert(first_order > 0);
+ assert(first_order > ht->min_alloc_order);
for (i = last_order; i >= first_order; i--) {
unsigned long len;
@@ -1268,7 +1270,7 @@ void cds_lfht_create_dummy(struct cds_lfht *ht, unsigned long size)
struct _cds_lfht_node *prev, *node;
unsigned long order, len, i, j;
- ht->t.tbl[0] = calloc(1, sizeof(struct _cds_lfht_node));
+ ht->t.tbl[0] = calloc(1, ht->min_alloc_size * sizeof(struct _cds_lfht_node));
assert(ht->t.tbl[0]);
dbg_printf("create dummy: order %lu index %lu hash %lu\n", 0, 0, 0);
@@ -1277,8 +1279,12 @@ void cds_lfht_create_dummy(struct cds_lfht *ht, unsigned long size)
for (order = 1; order < get_count_order_ulong(size) + 1; order++) {
len = 1UL << (order - 1);
- ht->t.tbl[order] = calloc(1, len * sizeof(struct _cds_lfht_node));
- assert(ht->t.tbl[order]);
+ if (order <= ht->min_alloc_order) {
+ ht->t.tbl[order] = (void *)(ht->t.tbl[0]->nodes + len);
+ } else {
+ ht->t.tbl[order] = calloc(1, len * sizeof(struct _cds_lfht_node));
+ assert(ht->t.tbl[order]);
+ }
i = 0;
prev = ht->t.tbl[i]->nodes;
@@ -1305,6 +1311,7 @@ struct cds_lfht *_cds_lfht_new(cds_lfht_hash_fct hash_fct,
cds_lfht_compare_fct compare_fct,
unsigned long hash_seed,
unsigned long init_size,
+ unsigned long min_alloc_size,
int flags,
void (*cds_lfht_call_rcu)(struct rcu_head *head,
void (*func)(struct rcu_head *head)),
@@ -1320,9 +1327,14 @@ struct cds_lfht *_cds_lfht_new(cds_lfht_hash_fct hash_fct,
struct cds_lfht *ht;
unsigned long order;
+ /* min_alloc_size must be power of two */
+ if (!min_alloc_size || (min_alloc_size & (min_alloc_size - 1)))
+ return NULL;
/* init_size must be power of two */
- if (init_size && (init_size & (init_size - 1)))
+ if (!init_size || (init_size & (init_size - 1)))
return NULL;
+ min_alloc_size = max(min_alloc_size, MIN_TABLE_SIZE);
+ init_size = max(init_size, min_alloc_size);
ht = calloc(1, sizeof(struct cds_lfht));
assert(ht);
ht->hash_fct = hash_fct;
@@ -1341,10 +1353,12 @@ struct cds_lfht *_cds_lfht_new(cds_lfht_hash_fct hash_fct,
/* this mutex should not nest in read-side C.S. */
pthread_mutex_init(&ht->resize_mutex, NULL);
ht->flags = flags;
- order = get_count_order_ulong(max(init_size, MIN_TABLE_SIZE));
+ order = get_count_order_ulong(init_size);
ht->t.resize_target = 1UL << order;
cds_lfht_create_dummy(ht, 1UL << order);
ht->t.size = 1UL << order;
+ ht->min_alloc_size = min_alloc_size;
+ ht->min_alloc_order = get_count_order_ulong(min_alloc_size);
return ht;
}
@@ -1562,7 +1576,12 @@ int cds_lfht_delete_dummy(struct cds_lfht *ht)
bit_reverse_ulong(ht->t.tbl[order]->nodes[i].reverse_hash));
assert(is_dummy(ht->t.tbl[order]->nodes[i].next));
}
- poison_free(ht->t.tbl[order]);
+
+ if (order == ht->min_alloc_order)
+ poison_free(ht->t.tbl[0]);
+ else if (order > ht->min_alloc_order)
+ poison_free(ht->t.tbl[order]);
+ /* Nothing to delete for order < ht->min_alloc_order */
}
return 0;
}
@@ -1663,7 +1682,7 @@ void _do_cds_lfht_shrink(struct cds_lfht *ht,
{
unsigned long old_order, new_order;
- new_size = max(new_size, MIN_TABLE_SIZE);
+ new_size = max(new_size, ht->min_alloc_size);
old_order = get_count_order_ulong(old_size);
new_order = get_count_order_ulong(new_size);
dbg_printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n",
@@ -1713,7 +1732,7 @@ static
void resize_target_update_count(struct cds_lfht *ht,
unsigned long count)
{
- count = max(count, MIN_TABLE_SIZE);
+ count = max(count, ht->min_alloc_size);
uatomic_set(&ht->t.resize_target, count);
}
diff --git a/tests/test_urcu_hash.c b/tests/test_urcu_hash.c
index db45c8c..70db8b3 100644
--- a/tests/test_urcu_hash.c
+++ b/tests/test_urcu_hash.c
@@ -888,7 +888,7 @@ int main(int argc, char **argv)
*/
rcu_register_thread();
test_ht = cds_lfht_new(test_hash, test_compare, 0x42UL,
- init_hash_size,
+ init_hash_size, 1,
opt_auto_resize ? CDS_LFHT_AUTO_RESIZE : 0, NULL);
ret = populate_hash();
assert(!ret);
diff --git a/urcu/rculfhash.h b/urcu/rculfhash.h
index 1376b5a..fd67b6b 100644
--- a/urcu/rculfhash.h
+++ b/urcu/rculfhash.h
@@ -103,6 +103,7 @@ struct cds_lfht *_cds_lfht_new(cds_lfht_hash_fct hash_fct,
cds_lfht_compare_fct compare_fct,
unsigned long hash_seed,
unsigned long init_size,
+ unsigned long min_alloc_size,
int flags,
void (*cds_lfht_call_rcu)(struct rcu_head *head,
void (*func)(struct rcu_head *head)),
@@ -121,6 +122,7 @@ struct cds_lfht *_cds_lfht_new(cds_lfht_hash_fct hash_fct,
* @compare_fct: the key comparison function.
* @hash_seed: the seed for hash function.
* @init_size: number of nodes to allocate initially. Must be power of two.
+ * @min_alloc_size: the smallest allocation size to use. Must be power of two.
* @flags: hash table creation flags (can be combined with bitwise or: '|').
* 0: no flags.
* CDS_LFHT_AUTO_RESIZE: automatically resize hash table.
@@ -143,11 +145,12 @@ struct cds_lfht *cds_lfht_new(cds_lfht_hash_fct hash_fct,
cds_lfht_compare_fct compare_fct,
unsigned long hash_seed,
unsigned long init_size,
+ unsigned long min_alloc_size,
int flags,
pthread_attr_t *attr)
{
return _cds_lfht_new(hash_fct, compare_fct, hash_seed,
- init_size, flags,
+ init_size, min_alloc_size, flags,
call_rcu, synchronize_rcu, rcu_read_lock,
rcu_read_unlock, rcu_thread_offline,
rcu_thread_online, rcu_register_thread,
--
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com
More information about the lttng-dev
mailing list