From 468cdd91c3bc21acde1d98250def7d9330204b8e Mon Sep 17 00:00:00 2001 From: Joe Stringer Date: Tue, 12 Aug 2014 11:12:12 +1200 Subject: [PATCH] hash: Add 128-bit murmurhash. Add the 128-bit murmurhash by Austin Appleby, r150 from: http://code.google.com/p/smhasher/source/browse/trunk/MurmurHash3.cpp Signed-off-by: Joe Stringer Acked-by: Ben Pfaff --- include/openvswitch/types.h | 14 ++ lib/hash.c | 266 +++++++++++++++++++++++++++++++++++- lib/hash.h | 11 +- tests/test-hash.c | 83 +++++++++++ 4 files changed, 368 insertions(+), 6 deletions(-) diff --git a/include/openvswitch/types.h b/include/openvswitch/types.h index 54541a42b..2afb7b71f 100644 --- a/include/openvswitch/types.h +++ b/include/openvswitch/types.h @@ -81,6 +81,20 @@ typedef struct { #endif } ovs_32aligned_u64; +typedef union { + uint32_t u32[4]; + struct { + uint64_t lo, hi; + } u64; +} ovs_u128; + +/* Returns non-zero if the parameters have equal value. */ +static inline int +ovs_u128_equal(const ovs_u128 *a, const ovs_u128 *b) +{ + return (a->u64.hi == b->u64.hi) && (a->u64.lo == b->u64.lo); +} + /* A 64-bit value, in network byte order, that is only aligned on a 32-bit * boundary. */ typedef struct { diff --git a/lib/hash.c b/lib/hash.c index 71cd74c8f..1042c97f6 100644 --- a/lib/hash.c +++ b/lib/hash.c @@ -1,5 +1,5 @@ /* - * Copyright (c) 2008, 2009, 2010, 2012, 2013 Nicira, Inc. + * Copyright (c) 2008, 2009, 2010, 2012, 2013, 2014 Nicira, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -71,3 +71,267 @@ hash_words64__(const uint64_t p[], size_t n_words, uint64_t basis) { return hash_words64_inline(p, n_words, basis); } + +#if !(defined(__x86_64__)) +void +hash_bytes128(const void *p_, size_t len, uint32_t basis, ovs_u128 *out) +{ + const uint32_t c1 = 0x239b961b; + const uint32_t c2 = 0xab0e9789; + const uint32_t c3 = 0x38b34ae5; + const uint32_t c4 = 0xa1e38b93; + const uint8_t *tail, *data = (const uint8_t *)p_; + const uint32_t *blocks = (const uint32_t *)p_; + const int nblocks = len / 16; + uint32_t h1 = basis; + uint32_t h2 = basis; + uint32_t h3 = basis; + uint32_t h4 = basis; + uint32_t k1, k2, k3, k4; + + /* Body */ + for (int i = 0; i < nblocks; i++) { + uint32_t k1 = get_unaligned_u32(&blocks[i * 4 + 0]); + uint32_t k2 = get_unaligned_u32(&blocks[i * 4 + 1]); + uint32_t k3 = get_unaligned_u32(&blocks[i * 4 + 2]); + uint32_t k4 = get_unaligned_u32(&blocks[i * 4 + 3]); + + k1 *= c1; + k1 = hash_rot(k1, 15); + k1 *= c2; + h1 ^= k1; + + h1 = hash_rot(h1, 19); + h1 += h2; + h1 = h1 * 5 + 0x561ccd1b; + + k2 *= c2; + k2 = hash_rot(k2, 16); + k2 *= c3; + h2 ^= k2; + + h2 = hash_rot(h2, 17); + h2 += h3; + h2 = h2 * 5 + 0x0bcaa747; + + k3 *= c3; + k3 = hash_rot(k3, 17); + k3 *= c4; + h3 ^= k3; + + h3 = hash_rot(h3, 15); + h3 += h4; + h3 = h3 * 5 + 0x96cd1c35; + + k4 *= c4; + k4 = hash_rot(k4, 18); + k4 *= c1; + h4 ^= k4; + + h4 = hash_rot(h4, 13); + h4 += h1; + h4 = h4 * 5 + 0x32ac3b17; + } + + /* Tail */ + k1 = k2 = k3 = k4 = 0; + tail = data + nblocks * 16; + switch (len & 15) { + case 15: + k4 ^= tail[14] << 16; + case 14: + k4 ^= tail[13] << 8; + case 13: + k4 ^= tail[12] << 0; + k4 *= c4; + k4 = hash_rot(k4, 18); + k4 *= c1; + h4 ^= k4; + + case 12: + k3 ^= tail[11] << 24; + case 11: + k3 ^= tail[10] << 16; + case 10: + k3 ^= tail[9] << 8; + case 9: + k3 ^= tail[8] << 0; + k3 *= c3; + k3 = hash_rot(k3, 17); + k3 *= c4; + h3 ^= k3; + + case 8: + k2 ^= tail[7] << 24; + case 7: + k2 ^= tail[6] << 16; + case 6: + k2 ^= tail[5] << 8; + case 5: + k2 ^= tail[4] << 0; + k2 *= c2; + k2 = hash_rot(k2, 16); + k2 *= c3; + h2 ^= k2; + + case 4: + k1 ^= tail[3] << 24; + case 3: + k1 ^= tail[2] << 16; + case 2: + k1 ^= tail[1] << 8; + case 1: + k1 ^= tail[0] << 0; + k1 *= c1; + k1 = hash_rot(k1, 15); + k1 *= c2; + h1 ^= k1; + }; + + /* Finalization */ + h1 ^= len; + h2 ^= len; + h3 ^= len; + h4 ^= len; + + h1 += h2; + h1 += h3; + h1 += h4; + h2 += h1; + h3 += h1; + h4 += h1; + + h1 = mhash_finish(h1); + h2 = mhash_finish(h2); + h3 = mhash_finish(h3); + h4 = mhash_finish(h4); + + h1 += h2; + h1 += h3; + h1 += h4; + h2 += h1; + h3 += h1; + h4 += h1; + + out->u32[0] = h1; + out->u32[1] = h2; + out->u32[2] = h3; + out->u32[3] = h4; +} + +#else /* __x86_64__ */ + +static inline uint64_t +hash_rot64(uint64_t x, int8_t r) +{ + return (x << r) | (x >> (64 - r)); +} + +static inline uint64_t +fmix64(uint64_t k) +{ + k ^= k >> 33; + k *= 0xff51afd7ed558ccdULL; + k ^= k >> 33; + k *= 0xc4ceb9fe1a85ec53ULL; + k ^= k >> 33; + + return k; +} + +void +hash_bytes128(const void *p_, size_t len, uint32_t basis, ovs_u128 *out) +{ + const uint64_t c1 = 0x87c37b91114253d5ULL; + const uint64_t c2 = 0x4cf5ad432745937fULL; + const uint8_t *tail, *data = (const uint8_t *)p_; + const uint64_t *blocks = (const uint64_t *)p_; + const int nblocks = len / 16; + uint64_t h1 = basis; + uint64_t h2 = basis; + uint64_t k1, k2; + + /* Body */ + for (int i = 0; i < nblocks; i++) { + k1 = get_unaligned_u64(&blocks[i * 2 + 0]); + k2 = get_unaligned_u64(&blocks[i * 2 + 1]); + + k1 *= c1; + k1 = hash_rot64(k1, 31); + k1 *= c2; + h1 ^= k1; + + h1 = hash_rot64(h1, 27); + h1 += h2; + h1 = h1 * 5 + 0x52dce729; + + k2 *= c2; + k2 = hash_rot64(k2, 33); + k2 *= c1; + h2 ^= k2; + + h2 = hash_rot64(h2, 31); + h2 += h1; + h2 = h2 * 5 + 0x38495ab5; + } + + /* Tail */ + k1 = 0; + k2 = 0; + tail = data + nblocks * 16; + switch (len & 15) { + case 15: + k2 ^= ((uint64_t) tail[14]) << 48; + case 14: + k2 ^= ((uint64_t) tail[13]) << 40; + case 13: + k2 ^= ((uint64_t) tail[12]) << 32; + case 12: + k2 ^= ((uint64_t) tail[11]) << 24; + case 11: + k2 ^= ((uint64_t) tail[10]) << 16; + case 10: + k2 ^= ((uint64_t) tail[9]) << 8; + case 9: + k2 ^= ((uint64_t) tail[8]) << 0; + k2 *= c2; + k2 = hash_rot64(k2, 33); + k2 *= c1; + h2 ^= k2; + + case 8: + k1 ^= ((uint64_t) tail[7]) << 56; + case 7: + k1 ^= ((uint64_t) tail[6]) << 48; + case 6: + k1 ^= ((uint64_t) tail[5]) << 40; + case 5: + k1 ^= ((uint64_t) tail[4]) << 32; + case 4: + k1 ^= ((uint64_t) tail[3]) << 24; + case 3: + k1 ^= ((uint64_t) tail[2]) << 16; + case 2: + k1 ^= ((uint64_t) tail[1]) << 8; + case 1: + k1 ^= ((uint64_t) tail[0]) << 0; + k1 *= c1; + k1 = hash_rot64(k1, 31); + k1 *= c2; + h1 ^= k1; + }; + + /* Finalization */ + h1 ^= len; + h2 ^= len; + h1 += h2; + h2 += h1; + h1 = fmix64(h1); + h2 = fmix64(h2); + h1 += h2; + h2 += h1; + + out->u64.lo = h1; + out->u64.hi = h2; +} +#endif /* __x86_64__ */ diff --git a/lib/hash.h b/lib/hash.h index 6d3affca8..c2820dd5e 100644 --- a/lib/hash.h +++ b/lib/hash.h @@ -1,5 +1,5 @@ /* - * Copyright (c) 2008, 2009, 2010, 2012, 2013 Nicira, Inc. + * Copyright (c) 2008, 2009, 2010, 2012, 2013, 2014 Nicira, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -33,6 +33,8 @@ hash_rot(uint32_t x, int k) } uint32_t hash_bytes(const void *, size_t n_bytes, uint32_t basis); +void hash_bytes128(const void *_, size_t n_bytes, uint32_t basis, + ovs_u128 *out); static inline uint32_t hash_int(uint32_t x, uint32_t basis); static inline uint32_t hash_2words(uint32_t, uint32_t); @@ -72,9 +74,8 @@ static inline uint32_t mhash_add(uint32_t hash, uint32_t data) return hash * 5 + 0xe6546b64; } -static inline uint32_t mhash_finish(uint32_t hash, uint32_t n_bytes) +static inline uint32_t mhash_finish(uint32_t hash) { - hash ^= n_bytes; hash ^= hash >> 16; hash *= 0x85ebca6b; hash ^= hash >> 13; @@ -84,7 +85,7 @@ static inline uint32_t mhash_finish(uint32_t hash, uint32_t n_bytes) } #if !(defined(__SSE4_2__) && defined(__x86_64__)) -/* Mhash-based implemantation. */ +/* Mhash-based implementation. */ static inline uint32_t hash_add(uint32_t hash, uint32_t data) { @@ -93,7 +94,7 @@ static inline uint32_t hash_add(uint32_t hash, uint32_t data) static inline uint32_t hash_finish(uint32_t hash, uint32_t final) { - return mhash_finish(hash, final); + return mhash_finish(hash ^ final); } /* Returns the hash of the 'n' 32-bit words at 'p', starting from 'basis'. diff --git a/tests/test-hash.c b/tests/test-hash.c index 35b23e936..d7e2e6b6e 100644 --- a/tests/test-hash.c +++ b/tests/test-hash.c @@ -35,6 +35,22 @@ set_bit(uint32_t array[3], int bit) } } +static void +set_bit128(ovs_u128 array[16], int bit) +{ + assert(bit >= 0 && bit <= 2048); + memset(array, 0, sizeof(ovs_u128) * 16); + if (bit < 2048) { + int b = bit % 128; + + if (b < 64) { + array[bit / 128].u64.lo = UINT64_C(1) << (b % 64); + } else { + array[bit / 128].u64.hi = UINT64_C(1) << (b % 64); + } + } +} + static uint32_t hash_words_cb(uint32_t input) { @@ -53,6 +69,15 @@ hash_int_cb(uint32_t input) return hash_int(input, 0); } +static uint32_t +hash_bytes128_cb(uint32_t input) +{ + ovs_u128 hash; + + hash_bytes128(&input, sizeof input, 0, &hash); + return hash.u64.lo; +} + static void check_word_hash(uint32_t (*hash)(uint32_t), const char *name, int min_unique) @@ -118,6 +143,48 @@ check_3word_hash(uint32_t (*hash)(const uint32_t[], size_t, uint32_t), } } +static void +check_256byte_hash(void (*hash)(const void *, size_t, uint32_t, ovs_u128 *), + const char *name, const int min_unique) +{ + const uint64_t unique_mask = (UINT64_C(1) << min_unique) - 1; + const int n_bits = 256 * 8; + int i, j; + + for (i = 0; i < n_bits; i++) { + for (j = i + 1; j < n_bits; j++) { + OVS_PACKED(struct offset_ovs_u128 { + uint32_t a; + ovs_u128 b[16]; + }) in0_data; + ovs_u128 *in0, in1[16], in2[16]; + ovs_u128 out0, out1, out2; + + in0 = in0_data.b; + set_bit128(in0, i); + set_bit128(in1, i); + set_bit128(in2, j); + hash(in0, sizeof(ovs_u128) * 16, 0, &out0); + hash(in1, sizeof(ovs_u128) * 16, 0, &out1); + hash(in2, sizeof(ovs_u128) * 16, 0, &out2); + if (!ovs_u128_equal(&out0, &out1)) { + printf("%s hash not the same for non-64 aligned data " + "%016"PRIx64"%016"PRIx64" != %016"PRIx64"%016"PRIx64"\n", + name, out0.u64.lo, out0.u64.hi, out1.u64.lo, out1.u64.hi); + } + if ((out1.u64.lo & unique_mask) == (out2.u64.lo & unique_mask)) { + printf("%s has a partial collision:\n", name); + printf("hash(1 << %4d) == %016"PRIx64"%016"PRIx64"\n", i, + out1.u64.hi, out1.u64.lo); + printf("hash(1 << %4d) == %016"PRIx64"%016"PRIx64"\n", j, + out2.u64.hi, out2.u64.lo); + printf("The low-order %d bits of output are both " + "0x%"PRIx64"\n", min_unique, out1.u64.lo & unique_mask); + } + } + } +} + static void test_hash_main(int argc OVS_UNUSED, char *argv[] OVS_UNUSED) { @@ -176,6 +243,22 @@ test_hash_main(int argc OVS_UNUSED, char *argv[] OVS_UNUSED) * function. */ check_word_hash(hash_int_cb, "hash_int", 12); + check_word_hash(hash_bytes128_cb, "hash_bytes128", 12); + + /* Check that all hashes computed with hash_bytes128 with 1-bit (or no + * 1-bits) set within 16 128-bit words have different values in their + * lowest 23 bits. + * + * Given a random distribution, the probability of at least one collision + * in any set of 23 bits is approximately + * + * 1 - ((2**23 - 1)/2**23)**C(2049,2) + * == 1 - (8,388,607/8,388,608)**2,098,176 + * =~ 0.22 + * + * so we are doing pretty well to not have any collisions in 23 bits. + */ + check_256byte_hash(hash_bytes128, "hash_bytes128", 23); } OVSTEST_REGISTER("test-hash", test_hash_main); -- 2.20.1