The lock-free algorithm has caused significant lookup performance regression for certain use cases. The regression is attributed to the use of non-relaxed memory orderings. 2 versions of the lookup functions are created. One that uses the RW lock and the one that is lock-free. This restores the performance regression caused for use cases that used RW lock version of the lookup function.
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 | 44 ++++++++++++++++++++++++------- 1 file changed, 34 insertions(+), 10 deletions(-) diff --git a/lib/librte_hash/rte_cuckoo_hash.c b/lib/librte_hash/rte_cuckoo_hash.c index 9390dc5e4..7e1a9ac96 100644 --- a/lib/librte_hash/rte_cuckoo_hash.c +++ b/lib/librte_hash/rte_cuckoo_hash.c @@ -1129,10 +1129,11 @@ rte_hash_add_key_data(const struct rte_hash *h, const void *key, void *data) return ret; } -/* Search one bucket to find the match key */ +/* Search one bucket to find the match key - uses rw lock */ static inline int32_t -search_one_bucket(const struct rte_hash *h, const void *key, uint16_t sig, - void **data, const struct rte_hash_bucket *bkt) +search_one_bucket_l(const struct rte_hash *h, const void *key, + uint16_t sig, void **data, + const struct rte_hash_bucket *bkt) { int i; struct rte_hash_key *k, *keys = h->key_store; @@ -1191,8 +1192,8 @@ search_one_bucket_lf(const struct rte_hash *h, const void *key, uint16_t sig, } static inline int32_t -__rte_hash_lookup_with_hash(const struct rte_hash *h, const void *key, - hash_sig_t sig, void **data) +__rte_hash_lookup_with_hash_l(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; @@ -1207,7 +1208,7 @@ __rte_hash_lookup_with_hash(const struct rte_hash *h, const void *key, /* Check if key is in primary location */ bkt = &h->buckets[prim_bucket_idx]; - ret = search_one_bucket(h, key, short_sig, data, bkt); + ret = search_one_bucket_l(h, key, short_sig, data, bkt); if (ret != -1) { __hash_rw_reader_unlock(h); return ret; @@ -1217,7 +1218,7 @@ __rte_hash_lookup_with_hash(const struct rte_hash *h, const void *key, /* Check if key is in secondary location */ FOR_EACH_BUCKET(cur_bkt, bkt) { - ret = search_one_bucket(h, key, short_sig, + ret = search_one_bucket_l(h, key, short_sig, data, cur_bkt); if (ret != -1) { __hash_rw_reader_unlock(h); @@ -1291,6 +1292,16 @@ __rte_hash_lookup_with_hash_lf(const struct rte_hash *h, const void *key, return -ENOENT; } +static inline int32_t +__rte_hash_lookup_with_hash(const struct rte_hash *h, const void *key, + hash_sig_t sig, void **data) +{ + if (h->readwrite_concur_lf_support) + return __rte_hash_lookup_with_hash_lf(h, key, sig, data); + else + return __rte_hash_lookup_with_hash_l(h, key, sig, data); +} + int32_t rte_hash_lookup_with_hash(const struct rte_hash *h, const void *key, hash_sig_t sig) @@ -1592,7 +1603,7 @@ compare_signatures(uint32_t *prim_hash_matches, uint32_t *sec_hash_matches, #define PREFETCH_OFFSET 4 static inline void -__rte_hash_lookup_bulk(const struct rte_hash *h, const void **keys, +__rte_hash_lookup_bulk_l(const struct rte_hash *h, const void **keys, int32_t num_keys, int32_t *positions, uint64_t *hit_mask, void *data[]) { @@ -1762,10 +1773,10 @@ __rte_hash_lookup_bulk(const struct rte_hash *h, const void **keys, next_bkt = secondary_bkt[i]->next; FOR_EACH_BUCKET(cur_bkt, next_bkt) { if (data != NULL) - ret = search_one_bucket(h, keys[i], + ret = search_one_bucket_l(h, keys[i], sig[i], &data[i], cur_bkt); else - ret = search_one_bucket(h, keys[i], + ret = search_one_bucket_l(h, keys[i], sig[i], NULL, cur_bkt); if (ret != -1) { positions[i] = ret; @@ -2005,6 +2016,19 @@ __rte_hash_lookup_bulk_lf(const struct rte_hash *h, const void **keys, *hit_mask = hits; } +static inline void +__rte_hash_lookup_bulk(const struct rte_hash *h, const void **keys, + int32_t num_keys, int32_t *positions, + uint64_t *hit_mask, void *data[]) +{ + if (h->readwrite_concur_lf_support) + return __rte_hash_lookup_bulk_lf(h, keys, num_keys, + positions, hit_mask, data); + else + return __rte_hash_lookup_bulk_l(h, keys, num_keys, + positions, hit_mask, data); +} + int rte_hash_lookup_bulk(const struct rte_hash *h, const void **keys, uint32_t num_keys, int32_t *positions) -- 2.17.1