[PATCH v5 5/7] hash: add support for common small key sizes

[Stephen Hemminger]

Add new compare functions for common small key sizes.

Fill in more key sizes to ensure more complete coverage of
special cases.

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

Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
Acked-by: Morten Brørup <mb at smartsharesystems.com>
---
 app/test/test_hash.c       |  12 +-
 lib/hash/rte_cuckoo_hash.c | 233 +++++++++++++++++++++++++++----------
 2 files changed, 179 insertions(+), 66 deletions(-)

diff --git a/app/test/test_hash.c b/app/test/test_hash.c
index a70e2620c0..1d140ec2cc 100644
--- a/app/test/test_hash.c
+++ b/app/test/test_hash.c
@@ -35,8 +35,16 @@
  */
 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};
-#define MAX_KEYSIZE 64
+
+/*
+ * Test common hash key lengths. Make sure and cover all the special cases
+ * in the cmp_jump_table.
+ */
+static uint32_t hashtest_key_lens[] = {
+	0, 1, 2, 3, 4, 5, 6, 7, 8, 10, 11, 12, 14, 15, 16, 18, 20,
+	21, 31, 32, 33, 36, 48, 63, 64, 80, 96, 112, 128, 254
+};
+#define MAX_KEYSIZE 256
 /******************************************************************************/
 #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 ce66308c5e..e8e625b369 100644
--- a/lib/hash/rte_cuckoo_hash.c
+++ b/lib/hash/rte_cuckoo_hash.c
@@ -49,9 +49,20 @@ RTE_LOG_REGISTER_DEFAULT(hash_logtype, INFO);
  * Not in rte_cuckoo_hash.h to avoid ABI issues.
  */
 enum cmp_jump_table_case {
-	KEY_CUSTOM = 0,
+	KEY_CUSTOM,
+	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_20_BYTES,
 	KEY_32_BYTES,
+	KEY_36_BYTES,
 	KEY_48_BYTES,
 	KEY_64_BYTES,
 	KEY_80_BYTES,
@@ -62,6 +73,17 @@ enum cmp_jump_table_case {
 	NUM_KEY_CMP_CASES,
 };
 
+/* Table of custom key sizes. */
+static const unsigned int cmp_jump_key_size[] = {
+	0,	/* Custom */
+	2,	3,	4,	5,	6,	8,	10,	12,	14,	16,	20,
+	32,	36,	48,	64,	80,	96,	112,	128,
+	UINT32_MAX /* Other */
+};
+
+static_assert(RTE_DIM(cmp_jump_key_size) == NUM_KEY_CMP_CASES,
+	      "cmp_jump_key_size table mismatch");
+
 /*
  * Comparison functions for different key sizes.
  * Each function is only called with a specific fixed key size.
@@ -85,56 +107,154 @@ 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 __rte_unused)
+{
+	return rte_hash_k2_cmp_eq(key1, key2, 2)
+		| (((const uint8_t *)key1)[2] ^ ((const uint8_t *)key2)[2]);
+}
+
+static inline 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 __rte_unused)
+{
+	const uint8_t *k1 = key1;
+	const uint8_t *k2 = key2;
+
+	return rte_hash_k4_cmp_eq(key1, key2, 4) | (k1[4] ^ k2[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 inline 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 __rte_unused)
+{
+	return rte_hash_k8_cmp_eq(key1, key2, 8) |
+		rte_hash_k2_cmp_eq((const uint8_t *)key1 + 8,
+				   (const uint8_t *)key2 + 8, 2);
+}
+
 static int
-rte_hash_k48_cmp_eq(const void *key1, const void *key2, size_t key_len)
+rte_hash_k12_cmp_eq(const void *key1, const void *key2, size_t key_len __rte_unused)
 {
-	return rte_hash_k16_cmp_eq(key1, key2, key_len) |
-		rte_hash_k16_cmp_eq((const uint8_t *) key1 + 16,
-				    (const uint8_t *) key2 + 16, key_len) |
-		rte_hash_k16_cmp_eq((const uint8_t *) key1 + 32,
-				    (const uint8_t *) key2 + 32, key_len);
+	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_k64_cmp_eq(const void *key1, const void *key2, size_t key_len)
+rte_hash_k14_cmp_eq(const void *key1, const void *key2, size_t key_len __rte_unused)
 {
-	return rte_hash_k32_cmp_eq(key1, key2, key_len) |
-		rte_hash_k32_cmp_eq((const uint8_t *) key1 + 32,
-				    (const uint8_t *) key2 + 32, key_len);
+	return rte_hash_k8_cmp_eq(key1, key2, 8) |
+		rte_hash_k6_cmp_eq((const uint8_t *)key1 + 8,
+				   (const uint8_t *)key2 + 8, 6);
 }
 
 static int
-rte_hash_k80_cmp_eq(const void *key1, const void *key2, size_t key_len)
+rte_hash_k20_cmp_eq(const void *key1, const void *key2, size_t key_len __rte_unused)
 {
-	return rte_hash_k64_cmp_eq(key1, key2, key_len) |
-		rte_hash_k16_cmp_eq((const uint8_t *) key1 + 64,
-				    (const uint8_t *) key2 + 64, key_len);
+	return rte_hash_k16_cmp_eq(key1, key2, 16) |
+		rte_hash_k4_cmp_eq((const uint8_t *)key1 + 16,
+				   (const uint8_t *)key2 + 16, 4);
 }
 
 static int
-rte_hash_k96_cmp_eq(const void *key1, const void *key2, size_t key_len)
+rte_hash_k36_cmp_eq(const void *key1, const void *key2, size_t key_len __rte_unused)
 {
-	return rte_hash_k64_cmp_eq(key1, key2, key_len) |
-		rte_hash_k32_cmp_eq((const uint8_t *) key1 + 64,
-				    (const uint8_t *) key2 + 64, key_len);
+	return rte_hash_k32_cmp_eq(key1, key2, 32) |
+		rte_hash_k4_cmp_eq((const uint8_t *)key1 + 32,
+				   (const uint8_t *)key2 + 32, 4);
 }
 
 static int
-rte_hash_k112_cmp_eq(const void *key1, const void *key2, size_t key_len)
+rte_hash_k48_cmp_eq(const void *key1, const void *key2, size_t key_len __rte_unused)
+{
+	return	rte_hash_k32_cmp_eq(key1, key2, 32) |
+		rte_hash_k16_cmp_eq((const uint8_t *)key1 + 32,
+				    (const uint8_t *)key2 + 32, 16);
+}
+
+static inline int
+rte_hash_k64_cmp_eq(const void *key1, const void *key2, size_t key_len __rte_unused)
 {
-	return rte_hash_k64_cmp_eq(key1, key2, key_len) |
-		rte_hash_k32_cmp_eq((const uint8_t *) key1 + 64,
-				    (const uint8_t *) key2 + 64, key_len) |
-		rte_hash_k16_cmp_eq((const uint8_t *) key1 + 96,
-				    (const uint8_t *) key2 + 96, key_len);
+	return rte_hash_k32_cmp_eq(key1, key2, 32) |
+		rte_hash_k32_cmp_eq((const uint8_t *)key1 + 32,
+				    (const uint8_t *)key2 + 32, 32);
 }
 
 static int
-rte_hash_k128_cmp_eq(const void *key1, const void *key2, size_t key_len)
+rte_hash_k80_cmp_eq(const void *key1, const void *key2, size_t key_len __rte_unused)
 {
-	return rte_hash_k64_cmp_eq(key1, key2, key_len) |
-		rte_hash_k64_cmp_eq((const uint8_t *) key1 + 64,
-				(const uint8_t *) key2 + 64, key_len);
+	return rte_hash_k64_cmp_eq(key1, key2, 64) |
+		rte_hash_k16_cmp_eq((const uint8_t *)key1 + 64,
+				    (const uint8_t *)key2 + 64, 64);
+}
+
+static int
+rte_hash_k96_cmp_eq(const void *key1, const void *key2, size_t key_len __rte_unused)
+{
+	return rte_hash_k64_cmp_eq(key1, key2, 64) |
+		rte_hash_k32_cmp_eq((const uint8_t *)key1 + 64,
+				    (const uint8_t *)key2 + 64, 32);
+}
+
+static int
+rte_hash_k112_cmp_eq(const void *key1, const void *key2, size_t key_len __rte_unused)
+{
+	return rte_hash_k64_cmp_eq(key1, key2, 64) |
+		rte_hash_k32_cmp_eq((const uint8_t *)key1 + 64,
+				    (const uint8_t *)key2 + 64, 32) |
+		rte_hash_k16_cmp_eq((const uint8_t *)key1 + 96,
+				    (const uint8_t *)key2 + 96, 16);
+}
+
+static int
+rte_hash_k128_cmp_eq(const void *key1, const void *key2, size_t key_len __rte_unused)
+{
+	return rte_hash_k64_cmp_eq(key1, key2, 64) |
+		rte_hash_k64_cmp_eq((const uint8_t *)key1 + 64,
+				    (const uint8_t *)key2 + 64, 64);
 }
 
 /* Enum used to select the implementation of the signature comparison function to use
@@ -226,8 +346,19 @@ 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_20_BYTES] = rte_hash_k20_cmp_eq,
 	[KEY_32_BYTES] = rte_hash_k32_cmp_eq,
+	[KEY_36_BYTES] = rte_hash_k36_cmp_eq,
 	[KEY_48_BYTES] = rte_hash_k48_cmp_eq,
 	[KEY_64_BYTES] = rte_hash_k64_cmp_eq,
 	[KEY_80_BYTES] = rte_hash_k80_cmp_eq,
@@ -510,41 +641,15 @@ rte_hash_create(const struct rte_hash_parameters *params)
 		goto err_unlock;
 	}
 
-	/* Select function to compare keys */
-	switch (params->key_len) {
-#if defined(RTE_ARCH_X86) || defined(RTE_ARCH_ARM64)
-	/*
-	 * If x86 architecture is used, select appropriate compare function,
-	 * which may use x86 intrinsics, otherwise use memcmp
-	 */
-	case 16:
-		h->cmp_jump_table_idx = KEY_16_BYTES;
-		break;
-	case 32:
-		h->cmp_jump_table_idx = KEY_32_BYTES;
-		break;
-	case 48:
-		h->cmp_jump_table_idx = KEY_48_BYTES;
-		break;
-	case 64:
-		h->cmp_jump_table_idx = KEY_64_BYTES;
-		break;
-	case 80:
-		h->cmp_jump_table_idx = KEY_80_BYTES;
-		break;
-	case 96:
-		h->cmp_jump_table_idx = KEY_96_BYTES;
-		break;
-	case 112:
-		h->cmp_jump_table_idx = KEY_112_BYTES;
-		break;
-	case 128:
-		h->cmp_jump_table_idx = KEY_128_BYTES;
-		break;
-#endif
-	default:
-		/* If key is not multiple of 16, use generic memcmp */
-		h->cmp_jump_table_idx = KEY_OTHER_BYTES;
+	/* fallback if no special case */
+	h->cmp_jump_table_idx = KEY_OTHER_BYTES;
+
+	/* Search table of enum values, 0 is reserved for custom */
+	for (unsigned int key_idx = KEY_2_BYTES; key_idx < KEY_OTHER_BYTES; key_idx++) {
+		if (params->key_len == cmp_jump_key_size[key_idx]) {
+			h->cmp_jump_table_idx = key_idx;
+			break;
+		}
 	}
 
 	if (use_local_cache) {
-- 
2.51.0