[PATCH v3 4/4] hash: add support for common small key sizes

Stephen Hemminger
2025-08-26T14:49:55Z

Add new compare functions for common small key sizes.

Bugzilla ID: 1775
Suggested-by: Morten Brørup <mb@smartsharesystems.com>
Reported-by: Mattias Rönnblom <mattias.ronnblom@ericsson.com>

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
app/test/test_hash.c | 4 +-
lib/hash/rte_cuckoo_hash.c | 100 +++++++++++++++++++++++++++++++++++++
2 files changed, 103 insertions(+), 1 deletion(-)

diff --git a/app/test/test_hash.c b/app/test/test_hash.c
index 5791fd7f4c..24588a4a96 100644
--- a/app/test/test_hash.c
+++ b/app/test/test_hash.c
@@ -35,7 +35,9 @@
*/
static rte_hash_function hashtest_funcs[] = {rte_jhash, rte_hash_crc};
static uint32_t hashtest_initvals[] = {0};
-static uint32_t hashtest_key_lens[] = {0, 2, 4, 5, 6, 7, 8, 10, 11, 15, 16, 21, 31, 32, 33, 63, 64};
+static uint32_t hashtest_key_lens[] = {
+ 0, 2, 3, 4, 5, 6, 7, 8, 10, 11, 12, 14, 15, 16, 21, 31, 32, 33, 63, 64
+};
#define MAX_KEYSIZE 64
/******************************************************************************/
#define LOCAL_FBK_HASH_ENTRIES_MAX (1 << 15)
diff --git a/lib/hash/rte_cuckoo_hash.c b/lib/hash/rte_cuckoo_hash.c
index 608d79d33d..78398abb2d 100644
--- a/lib/hash/rte_cuckoo_hash.c
+++ b/lib/hash/rte_cuckoo_hash.c
@@ -50,6 +50,15 @@ RTE_LOG_REGISTER_DEFAULT(hash_logtype, INFO);
*/
enum cmp_jump_table_case {
KEY_CUSTOM = 0,
+ KEY_2_BYTES,
+ KEY_3_BYTES,
+ KEY_4_BYTES,
+ KEY_5_BYTES,
+ KEY_6_BYTES,
+ KEY_8_BYTES,
+ KEY_10_BYTES,
+ KEY_12_BYTES,
+ KEY_14_BYTES,
KEY_16_BYTES,
KEY_32_BYTES,
KEY_48_BYTES,
@@ -85,6 +94,88 @@ enum cmp_jump_table_case {
#include "rte_cmp_generic.h"
#endif

+static inline int
+rte_hash_k2_cmp_eq(const void *key1, const void *key2, size_t key_len __rte_unused)
+{
+ const unaligned_uint16_t *k1 = key1;
+ const unaligned_uint16_t *k2 = key2;
+
+ return k1[0] ^ k2[0];
+}
+
+static int
+rte_hash_k3_cmp_eq(const void *key1, const void *key2, size_t key_len)
+{
+ return rte_hash_k2_cmp_eq(key1, key2, key_len)
+ | (((const uint8_t *)key1)[2] ^ ((const uint8_t *)key2)[2]);
+}
+
+static int
+rte_hash_k4_cmp_eq(const void *key1, const void *key2, size_t key_len __rte_unused)
+{
+ const unaligned_uint32_t *k1 = key1;
+ const unaligned_uint32_t *k2 = key2;
+
+ return k1[0] ^ k2[0];
+}
+
+static int
+rte_hash_k5_cmp_eq(const void *key1, const void *key2, size_t key_len)
+{
+ return rte_hash_k4_cmp_eq(key1, key2, key_len) |
+ (((const uint8_t *)key1)[4] ^ ((const uint8_t *)key2)[4]);
+}
+
+static int
+rte_hash_k6_cmp_eq(const void *key1, const void *key2, size_t key_len __rte_unused)
+{
+ const unaligned_uint16_t *k1 = key1;
+ const unaligned_uint16_t *k2 = key2;
+
+ return (k1[0] ^ k2[0]) | (k1[1] ^ k2[1]) | (k1[2] ^ k2[2]);
+}
+
+static int
+rte_hash_k8_cmp_eq(const void *key1, const void *key2, size_t key_len __rte_unused)
+{
+#ifdef RTE_ARCH_64
+ const unaligned_uint64_t *k1 = key1;
+ const unaligned_uint64_t *k2 = key2;
+
+ return !!(k1[0] ^ k2[0]);
+#else
+ const unaligned_uint32_t *k1 = key1;
+ const unaligned_uint32_t *k2 = key2;
+
+ return (k1[0] ^ k2[0]) | (k1[1] ^ k2[1]);
+#endif
+}
+
+static int
+rte_hash_k10_cmp_eq(const void *key1, const void *key2, size_t key_len)
+{
+ return rte_hash_k8_cmp_eq(key1, key2, key_len) |
+ rte_hash_k2_cmp_eq((const uint8_t *)key1 + 8,
+ (const uint8_t *)key2 + 8, key_len);
+}
+
+static int
+rte_hash_k12_cmp_eq(const void *key1, const void *key2, size_t key_len __rte_unused)
+{
+ const unaligned_uint32_t *k1 = key1;
+ const unaligned_uint32_t *k2 = key2;
+
+ return (k1[0] ^ k2[0]) | (k1[1] ^ k2[1]) | (k1[2] ^ k2[2]);
+}
+
+static int
+rte_hash_k14_cmp_eq(const void *key1, const void *key2, size_t key_len __rte_unused)
+{
+ return rte_hash_k8_cmp_eq(key1, key2, key_len) |
+ rte_hash_k6_cmp_eq((const uint8_t *)key1 + 8,
+ (const uint8_t *)key2 + 8, key_len);
+}
+
static int
rte_hash_k48_cmp_eq(const void *key1, const void *key2, size_t key_len)
{
@@ -226,6 +317,15 @@ void rte_hash_set_cmp_func(struct rte_hash *h, rte_hash_cmp_eq_t func)
*/
static const rte_hash_cmp_eq_t cmp_jump_table[NUM_KEY_CMP_CASES] = {
[KEY_CUSTOM] = NULL,
+ [KEY_2_BYTES] = rte_hash_k2_cmp_eq,
+ [KEY_3_BYTES] = rte_hash_k3_cmp_eq,
+ [KEY_4_BYTES] = rte_hash_k4_cmp_eq,
+ [KEY_5_BYTES] = rte_hash_k5_cmp_eq,
+ [KEY_6_BYTES] = rte_hash_k6_cmp_eq,
+ [KEY_8_BYTES] = rte_hash_k8_cmp_eq,
+ [KEY_10_BYTES] = rte_hash_k10_cmp_eq,
+ [KEY_12_BYTES] = rte_hash_k12_cmp_eq,
+ [KEY_14_BYTES] = rte_hash_k14_cmp_eq,
[KEY_16_BYTES] = rte_hash_k16_cmp_eq,
[KEY_32_BYTES] = rte_hash_k32_cmp_eq,
[KEY_48_BYTES] = rte_hash_k48_cmp_eq,
--
2.47.2