Copy and create the lock-free versions of lookup
functions.
This is an intermediate commit meant to ease the
review process.
Fixes: e605a1d36 ("hash: add lock-free r/w concurrency")
Cc: honnappa.nagaraha...@arm.com
Suggested-by: Jerin Jacob <jerin.ja...@caviumnetworks.com>
Signed-off-by: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com>
Reviewed-by: Ola Liljedahl <ola.liljed...@arm.com>
Reviewed-by: Gavin Hu <gavin...@arm.com>
---
lib/librte_hash/rte_cuckoo_hash.c | 325 ++++++++++++++++++++++++++++++
1 file changed, 325 insertions(+)
diff --git a/lib/librte_hash/rte_cuckoo_hash.c
b/lib/librte_hash/rte_cuckoo_hash.c
index 5ddcccd87..874d77f1c 100644
--- a/lib/librte_hash/rte_cuckoo_hash.c
+++ b/lib/librte_hash/rte_cuckoo_hash.c
@@ -1162,6 +1162,39 @@ search_one_bucket(const struct rte_hash *h, const void
*key, uint16_t sig,
return -1;
}
+/* Search one bucket to find the match key */
+static inline int32_t
+search_one_bucket_lf(const struct rte_hash *h, const void *key, uint16_t sig,
+ void **data, const struct rte_hash_bucket *bkt)
+{
+ int i;
+ uint32_t key_idx;
+ void *pdata;
+ struct rte_hash_key *k, *keys = h->key_store;
+
+ for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
+ key_idx = __atomic_load_n(&bkt->key_idx[i],
+ __ATOMIC_ACQUIRE);
+ if (bkt->sig_current[i] == sig && key_idx != EMPTY_SLOT) {
+ k = (struct rte_hash_key *) ((char *)keys +
+ key_idx * h->key_entry_size);
+ pdata = __atomic_load_n(&k->pdata,
+ __ATOMIC_ACQUIRE);
+
+ if (rte_hash_cmp_eq(key, k->key, h) == 0) {
+ if (data != NULL)
+ *data = pdata;
+ /*
+ * Return index where key is stored,
+ * subtracting the first dummy index
+ */
+ return key_idx - 1;
+ }
+ }
+ }
+ return -1;
+}
+
static inline int32_t
__rte_hash_lookup_with_hash(const struct rte_hash *h, const void *key,
hash_sig_t sig, void **data)
@@ -1227,6 +1260,71 @@ __rte_hash_lookup_with_hash(const struct rte_hash *h,
const void *key,
return -ENOENT;
}
+static inline int32_t
+__rte_hash_lookup_with_hash_lf(const struct rte_hash *h, const void *key,
+ hash_sig_t sig, void **data)
+{
+ uint32_t prim_bucket_idx, sec_bucket_idx;
+ struct rte_hash_bucket *bkt, *cur_bkt;
+ uint32_t cnt_b, cnt_a;
+ int ret;
+ uint16_t short_sig;
+
+ short_sig = get_short_sig(sig);
+ prim_bucket_idx = get_prim_bucket_index(h, sig);
+ sec_bucket_idx = get_alt_bucket_index(h, prim_bucket_idx, short_sig);
+
+ __hash_rw_reader_lock(h);
+
+ do {
+ /* Load the table change counter before the lookup
+ * starts. Acquire semantics will make sure that
+ * loads in search_one_bucket are not hoisted.
+ */
+ cnt_b = __atomic_load_n(h->tbl_chng_cnt,
+ __ATOMIC_ACQUIRE);
+
+ /* Check if key is in primary location */
+ bkt = &h->buckets[prim_bucket_idx];
+ ret = search_one_bucket(h, key, short_sig, data, bkt);
+ if (ret != -1) {
+ __hash_rw_reader_unlock(h);
+ return ret;
+ }
+ /* Calculate secondary hash */
+ bkt = &h->buckets[sec_bucket_idx];
+
+ /* Check if key is in secondary location */
+ FOR_EACH_BUCKET(cur_bkt, bkt) {
+ ret = search_one_bucket(h, key, short_sig,
+ data, cur_bkt);
+ if (ret != -1) {
+ __hash_rw_reader_unlock(h);
+ return ret;
+ }
+ }
+
+ /* The loads of sig_current in search_one_bucket
+ * should not move below the load from tbl_chng_cnt.
+ */
+ __atomic_thread_fence(__ATOMIC_ACQUIRE);
+ /* Re-read the table change counter to check if the
+ * table has changed during search. If yes, re-do
+ * the search.
+ * This load should not get hoisted. The load
+ * acquires on cnt_b, key index in primary bucket
+ * and key index in secondary bucket will make sure
+ * that it does not get hoisted.
+ */
+ cnt_a = __atomic_load_n(h->tbl_chng_cnt,
+ __ATOMIC_ACQUIRE);
+ } while (cnt_b != cnt_a);
+
+ __hash_rw_reader_unlock(h);
+
+ return -ENOENT;
+}
+
int32_t
rte_hash_lookup_with_hash(const struct rte_hash *h,
const void *key, hash_sig_t sig)
@@ -1754,6 +1852,233 @@ __rte_hash_lookup_bulk(const struct rte_hash *h, const
void **keys,
*hit_mask = hits;
}
+static inline void
+__rte_hash_lookup_bulk_lf(const struct rte_hash *h, const void **keys,
+ int32_t num_keys, int32_t *positions,
+ uint64_t *hit_mask, void *data[])
+{
+ uint64_t hits = 0;
+ int32_t i;
+ int32_t ret;
+ uint32_t prim_hash[RTE_HASH_LOOKUP_BULK_MAX];
+ uint32_t prim_index[RTE_HASH_LOOKUP_BULK_MAX];
+ uint32_t sec_index[RTE_HASH_LOOKUP_BULK_MAX];
+ uint16_t sig[RTE_HASH_LOOKUP_BULK_MAX];
+ const struct rte_hash_bucket *primary_bkt[RTE_HASH_LOOKUP_BULK_MAX];
+ const struct rte_hash_bucket *secondary_bkt[RTE_HASH_LOOKUP_BULK_MAX];
+ uint32_t prim_hitmask[RTE_HASH_LOOKUP_BULK_MAX] = {0};
+ uint32_t sec_hitmask[RTE_HASH_LOOKUP_BULK_MAX] = {0};
+ struct rte_hash_bucket *cur_bkt, *next_bkt;
+ void *pdata[RTE_HASH_LOOKUP_BULK_MAX];
+ uint32_t cnt_b, cnt_a;
+
+ /* Prefetch first keys */
+ for (i = 0; i < PREFETCH_OFFSET && i < num_keys; i++)
+ rte_prefetch0(keys[i]);
+
+ /*
+ * Prefetch rest of the keys, calculate primary and
+ * secondary bucket and prefetch them
+ */
+ for (i = 0; i < (num_keys - PREFETCH_OFFSET); i++) {
+ rte_prefetch0(keys[i + PREFETCH_OFFSET]);
+
+ prim_hash[i] = rte_hash_hash(h, keys[i]);
+
+ sig[i] = get_short_sig(prim_hash[i]);
+ prim_index[i] = get_prim_bucket_index(h, prim_hash[i]);
+ sec_index[i] = get_alt_bucket_index(h, prim_index[i], sig[i]);
+
+ primary_bkt[i] = &h->buckets[prim_index[i]];
+ secondary_bkt[i] = &h->buckets[sec_index[i]];
+
+ rte_prefetch0(primary_bkt[i]);
+ rte_prefetch0(secondary_bkt[i]);
+ }
+
+ /* Calculate and prefetch rest of the buckets */
+ for (; i < num_keys; i++) {
+ prim_hash[i] = rte_hash_hash(h, keys[i]);
+
+ sig[i] = get_short_sig(prim_hash[i]);
+ prim_index[i] = get_prim_bucket_index(h, prim_hash[i]);
+ sec_index[i] = get_alt_bucket_index(h, prim_index[i], sig[i]);
+
+ primary_bkt[i] = &h->buckets[prim_index[i]];
+ secondary_bkt[i] = &h->buckets[sec_index[i]];
+
+ rte_prefetch0(primary_bkt[i]);
+ rte_prefetch0(secondary_bkt[i]);
+ }
+
+ __hash_rw_reader_lock(h);
+ do {
+ /* Load the table change counter before the lookup
+ * starts. Acquire semantics will make sure that
+ * loads in compare_signatures are not hoisted.
+ */
+ cnt_b = __atomic_load_n(h->tbl_chng_cnt,
+ __ATOMIC_ACQUIRE);
+
+ /* Compare signatures and prefetch key slot of first hit */
+ for (i = 0; i < num_keys; i++) {
+ compare_signatures(&prim_hitmask[i], &sec_hitmask[i],
+ primary_bkt[i], secondary_bkt[i],
+ sig[i], h->sig_cmp_fn);
+
+ if (prim_hitmask[i]) {
+ uint32_t first_hit =
+ __builtin_ctzl(prim_hitmask[i])
+ >> 1;
+ uint32_t key_idx =
+ primary_bkt[i]->key_idx[first_hit];
+ const struct rte_hash_key *key_slot =
+ (const struct rte_hash_key *)(
+ (const char *)h->key_store +
+ key_idx * h->key_entry_size);
+ rte_prefetch0(key_slot);
+ continue;
+ }
+
+ if (sec_hitmask[i]) {
+ uint32_t first_hit =
+ __builtin_ctzl(sec_hitmask[i])
+ >> 1;
+ uint32_t key_idx =
+ secondary_bkt[i]->key_idx[first_hit];
+ const struct rte_hash_key *key_slot =
+ (const struct rte_hash_key *)(
+ (const char *)h->key_store +
+ key_idx * h->key_entry_size);
+ rte_prefetch0(key_slot);
+ }
+ }
+
+ /* Compare keys, first hits in primary first */
+ for (i = 0; i < num_keys; i++) {
+ positions[i] = -ENOENT;
+ while (prim_hitmask[i]) {
+ uint32_t hit_index =
+ __builtin_ctzl(prim_hitmask[i])
+ >> 1;
+ uint32_t key_idx =
+ __atomic_load_n(
+ &primary_bkt[i]->key_idx[hit_index],
+ __ATOMIC_ACQUIRE);
+ const struct rte_hash_key *key_slot =
+ (const struct rte_hash_key *)(
+ (const char *)h->key_store +
+ key_idx * h->key_entry_size);
+
+ if (key_idx != EMPTY_SLOT)
+ pdata[i] = __atomic_load_n(
+ &key_slot->pdata,
+ __ATOMIC_ACQUIRE);
+ /*
+ * If key index is 0, do not compare key,
+ * as it is checking the dummy slot
+ */
+ if (!!key_idx &
+ !rte_hash_cmp_eq(
+ key_slot->key, keys[i], h)) {
+ if (data != NULL)
+ data[i] = pdata[i];
+
+ hits |= 1ULL << i;
+ positions[i] = key_idx - 1;
+ goto next_key;
+ }
+ prim_hitmask[i] &= ~(3ULL << (hit_index << 1));
+ }
+
+ while (sec_hitmask[i]) {
+ uint32_t hit_index =
+ __builtin_ctzl(sec_hitmask[i])
+ >> 1;
+ uint32_t key_idx =
+ __atomic_load_n(
+ &secondary_bkt[i]->key_idx[hit_index],
+ __ATOMIC_ACQUIRE);
+ const struct rte_hash_key *key_slot =
+ (const struct rte_hash_key *)(
+ (const char *)h->key_store +
+ key_idx * h->key_entry_size);
+
+ if (key_idx != EMPTY_SLOT)
+ pdata[i] = __atomic_load_n(
+ &key_slot->pdata,
+ __ATOMIC_ACQUIRE);
+ /*
+ * If key index is 0, do not compare key,
+ * as it is checking the dummy slot
+ */
+
+ if (!!key_idx &
+ !rte_hash_cmp_eq(
+ key_slot->key, keys[i], h)) {
+ if (data != NULL)
+ data[i] = pdata[i];
+
+ hits |= 1ULL << i;
+ positions[i] = key_idx - 1;
+ goto next_key;
+ }
+ sec_hitmask[i] &= ~(3ULL << (hit_index << 1));
+ }
+next_key:
+ continue;
+ }
+
+ /* The loads of sig_current in compare_signatures
+ * should not move below the load from tbl_chng_cnt.
+ */
+ __atomic_thread_fence(__ATOMIC_ACQUIRE);
+ /* Re-read the table change counter to check if the
+ * table has changed during search. If yes, re-do
+ * the search.
+ * This load should not get hoisted. The load
+ * acquires on cnt_b, primary key index and secondary
+ * key index will make sure that it does not get
+ * hoisted.
+ */
+ cnt_a = __atomic_load_n(h->tbl_chng_cnt,
+ __ATOMIC_ACQUIRE);
+ } while (cnt_b != cnt_a);
+
+ /* all found, do not need to go through ext bkt */
+ if ((hits == ((1ULL << num_keys) - 1)) || !h->ext_table_support) {
+ if (hit_mask != NULL)
+ *hit_mask = hits;
+ __hash_rw_reader_unlock(h);
+ return;
+ }
+
+ /* need to check ext buckets for match */
+ for (i = 0; i < num_keys; i++) {
+ if ((hits & (1ULL << i)) != 0)
+ continue;
+ next_bkt = secondary_bkt[i]->next;
+ FOR_EACH_BUCKET(cur_bkt, next_bkt) {
+ if (data != NULL)
+ ret = search_one_bucket(h, keys[i],
+ sig[i], &data[i], cur_bkt);
+ else
+ ret = search_one_bucket(h, keys[i],
+ sig[i], NULL, cur_bkt);
+ if (ret != -1) {
+ positions[i] = ret;
+ hits |= 1ULL << i;
+ break;
+ }
+ }
+ }
+
+ __hash_rw_reader_unlock(h);
+
+ if (hit_mask != NULL)
+ *hit_mask = hits;
+}
+
int
rte_hash_lookup_bulk(const struct rte_hash *h, const void **keys,
uint32_t num_keys, int32_t *positions)
--
2.17.1
