From: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
To: yipeng1.wang@intel.com, sameh.gobriel@intel.com,
bruce.richardson@intel.com, pablo.de.lara.guarch@intel.com,
honnappa.nagarahalli@arm.com
Cc: gavin.hu@arm.com, ruifeng.wang@arm.com, dev@dpdk.org, nd@arm.com,
stable@dpdk.org
Subject: [dpdk-dev] [PATCH 1/3] lib/hash: use ordered loads only if signature matches
Date: Tue, 25 Jun 2019 16:15:18 -0500 [thread overview]
Message-ID: <20190625211520.43181-2-honnappa.nagarahalli@arm.com> (raw)
In-Reply-To: <20190625211520.43181-1-honnappa.nagarahalli@arm.com>
Relaxed signature comparison is done first. Further ordered loads
are done only if the signature matches. Any false positives are
caught by the full key comparison.
Fixes: e605a1d36 ("hash: add lock-free r/w concurrency")
Cc: stable@dpdk.org
Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Reviewed-by: Gavin Hu <gavin.hu@arm.com>
Tested-by: Ruifeng Wang <ruifeng.wang@arm.com>
---
lib/librte_hash/rte_cuckoo_hash.c | 35 ++++++++++++++++++-------------
1 file changed, 21 insertions(+), 14 deletions(-)
diff --git a/lib/librte_hash/rte_cuckoo_hash.c b/lib/librte_hash/rte_cuckoo_hash.c
index 953928f27..f37f6957d 100644
--- a/lib/librte_hash/rte_cuckoo_hash.c
+++ b/lib/librte_hash/rte_cuckoo_hash.c
@@ -1188,22 +1188,29 @@ search_one_bucket_lf(const struct rte_hash *h, const void *key, uint16_t sig,
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],
+ /* Signature comparison is done before the acquire-load
+ * of the key index to achieve better performance.
+ * Any false positives will be caught in full comparison
+ * of the key.
+ */
+ if (bkt->sig_current[i] == sig) {
+ 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 (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;
+ 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;
+ }
}
}
}
--
2.17.1
next prev parent reply other threads:[~2019-06-25 21:15 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-25 21:15 [dpdk-dev] [PATCH 0/3] lib/hash: perf improvements for lock-free Honnappa Nagarahalli
2019-06-25 21:15 ` Honnappa Nagarahalli [this message]
2019-06-28 18:04 ` [dpdk-dev] [PATCH 1/3] lib/hash: use ordered loads only if signature matches Wang, Yipeng1
2019-06-25 21:15 ` [dpdk-dev] [PATCH 2/3] lib/hash: load pData after full key compare Honnappa Nagarahalli
2019-06-28 18:40 ` Wang, Yipeng1
2019-07-02 4:35 ` Honnappa Nagarahalli
2019-07-04 0:39 ` Wang, Yipeng1
2019-07-05 5:33 ` Honnappa Nagarahalli
2019-07-08 16:44 ` Wang, Yipeng1
2019-06-25 21:15 ` [dpdk-dev] [PATCH 3/3] lib/hash: adjust tbl_chng_cnt position Honnappa Nagarahalli
2019-06-28 18:50 ` Wang, Yipeng1
2019-07-02 17:23 ` Honnappa Nagarahalli
2019-07-04 0:52 ` Wang, Yipeng1
2019-07-02 21:16 ` [dpdk-dev] [PATCH v2 0/2] lib/hash: perf improvements for lock-free Honnappa Nagarahalli
2019-07-02 21:16 ` [dpdk-dev] [PATCH v2 1/2] lib/hash: use ordered loads only if signature matches Honnappa Nagarahalli
2019-07-02 21:16 ` [dpdk-dev] [PATCH v2 2/2] lib/hash: load pData after full key compare Honnappa Nagarahalli
2019-07-04 11:13 ` [dpdk-dev] [PATCH v2 0/2] lib/hash: perf improvements for lock-free Jerin Jacob Kollanukkaran
2019-07-05 6:08 ` Honnappa Nagarahalli
2019-07-04 16:09 ` Thomas Monjalon
2019-07-05 6:14 ` Honnappa Nagarahalli
2019-07-05 6:29 ` Thomas Monjalon
2019-07-08 16:51 ` Wang, Yipeng1
2019-07-08 18:10 ` Thomas Monjalon
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