From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from foss.arm.com (usa-sjc-mx-foss1.foss.arm.com [217.140.101.70]) by dpdk.org (Postfix) with ESMTP id F21F14C94 for ; Fri, 9 Nov 2018 17:39:43 +0100 (CET) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 23EB515AB; Fri, 9 Nov 2018 08:39:43 -0800 (PST) Received: from qc2400f-1.austin.arm.com (qc2400f-1.austin.arm.com [10.118.12.122]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 94D893F5BD; Fri, 9 Nov 2018 08:39:42 -0800 (PST) From: Honnappa Nagarahalli To: bruce.richardson@intel.com, pablo.de.lara.guarch@intel.com Cc: dev@dpdk.org, jerin.jacob@caviumnetworks.com, hemant.agrawal@nxp.com, chaozhu@linux.vnet.ibm.com, yipeng1.wang@intel.com, dharmik.thakkar@arm.com, gavin.hu@arm.com, honnappa.nagarahalli@arm.com, nd@arm.com Date: Fri, 9 Nov 2018 10:39:14 -0600 Message-Id: <20181109163917.16845-2-honnappa.nagarahalli@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181109163917.16845-1-honnappa.nagarahalli@arm.com> References: <20181109163917.16845-1-honnappa.nagarahalli@arm.com> Subject: [dpdk-dev] [PATCH 1/4] hash: prepare for lock-free and rw-lock separation X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 09 Nov 2018 16:39:44 -0000 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.nagarahalli@arm.com Suggested-by: Jerin Jacob Signed-off-by: Honnappa Nagarahalli Reviewed-by: Ola Liljedahl Reviewed-by: Gavin Hu --- 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