From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pablo de Lara Subject: [PATCH v2 3/6] hash: update jhash function with the latest available Date: Fri, 24 Apr 2015 12:23:04 +0100 Message-ID: <1429874587-17939-4-git-send-email-pablo.de.lara.guarch@intel.com> References: <1429190819-27402-1-git-send-email-pablo.de.lara.guarch@intel.com> <1429874587-17939-1-git-send-email-pablo.de.lara.guarch@intel.com> To: dev-VfR2kkLFssw@public.gmane.org Return-path: In-Reply-To: <1429874587-17939-1-git-send-email-pablo.de.lara.guarch-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces-VfR2kkLFssw@public.gmane.org Sender: "dev" Jenkins hash function was developed originally in 1996, and was integrated in first versions of DPDK. The function has been improved in 2006, achieving up to 60% better performance, compared to the original one. This patch integrates that code into the rte_jhash library. Signed-off-by: Pablo de Lara --- lib/librte_hash/rte_jhash.h | 234 ++++++++++++++++++++++++++++++++----------- 1 files changed, 174 insertions(+), 60 deletions(-) diff --git a/lib/librte_hash/rte_jhash.h b/lib/librte_hash/rte_jhash.h index a4bf5a1..4ec1c39 100644 --- a/lib/librte_hash/rte_jhash.h +++ b/lib/librte_hash/rte_jhash.h @@ -1,7 +1,7 @@ /*- * BSD LICENSE * - * Copyright(c) 2010-2014 Intel Corporation. All rights reserved. + * Copyright(c) 2010-2015 Intel Corporation. All rights reserved. * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -45,38 +45,68 @@ extern "C" { #endif #include +#include +#include /* jhash.h: Jenkins hash support. * - * Copyright (C) 1996 Bob Jenkins (bob_jenkins-+9kZLMxy4yAbbCauIUEb2A@public.gmane.org) + * Copyright (C) 2006 Bob Jenkins (bob_jenkins-+9kZLMxy4yAbbCauIUEb2A@public.gmane.org) * * http://burtleburtle.net/bob/hash/ * * These are the credits from Bob's sources: * - * lookup2.c, by Bob Jenkins, December 1996, Public Domain. - * hash(), hash2(), hash3, and mix() are externally useful functions. - * Routines to test the hash are included if SELF_TEST is defined. - * You can use this free for any purpose. It has no warranty. + * lookup3.c, by Bob Jenkins, May 2006, Public Domain. + * + * These are functions for producing 32-bit hashes for hash table lookup. + * hashword(), hashlittle(), hashlittle2(), hashbig(), mix(), and final() + * are externally useful functions. Routines to test the hash are included + * if SELF_TEST is defined. You can use this free for any purpose. It's in + * the public domain. It has no warranty. * * $FreeBSD$ */ +#define rot(x, k) (((x) << (k)) | ((x) >> (32-(k)))) + /** @internal Internal function. NOTE: Arguments are modified. */ #define __rte_jhash_mix(a, b, c) do { \ - a -= b; a -= c; a ^= (c>>13); \ - b -= c; b -= a; b ^= (a<<8); \ - c -= a; c -= b; c ^= (b>>13); \ - a -= b; a -= c; a ^= (c>>12); \ - b -= c; b -= a; b ^= (a<<16); \ - c -= a; c -= b; c ^= (b>>5); \ - a -= b; a -= c; a ^= (c>>3); \ - b -= c; b -= a; b ^= (a<<10); \ - c -= a; c -= b; c ^= (b>>15); \ + a -= c; a ^= rot(c, 4); c += b; \ + b -= a; b ^= rot(a, 6); a += c; \ + c -= b; c ^= rot(b, 8); b += a; \ + a -= c; a ^= rot(c, 16); c += b; \ + b -= a; b ^= rot(a, 19); a += c; \ + c -= b; c ^= rot(b, 4); b += a; \ +} while (0) + +#define __rte_jhash_final(a, b, c) do { \ + c ^= b; c -= rot(b, 14); \ + a ^= c; a -= rot(c, 11); \ + b ^= a; b -= rot(a, 25); \ + c ^= b; c -= rot(b, 16); \ + a ^= c; a -= rot(c, 4); \ + b ^= a; b -= rot(a, 14); \ + c ^= b; c -= rot(b, 24); \ } while (0) /** The golden ratio: an arbitrary value. */ -#define RTE_JHASH_GOLDEN_RATIO 0x9e3779b9 +#define RTE_JHASH_GOLDEN_RATIO 0xdeadbeef + +#if RTE_BYTE_ORDER == RTE_LITTLE_ENDIAN +#define RTE_JHASH_BYTE0_SHIFT 0 +#define RTE_JHASH_BYTE1_SHIFT 8 +#define RTE_JHASH_BYTE2_SHIFT 16 +#define RTE_JHASH_BYTE3_SHIFT 24 +#else +#define RTE_JHASH_BYTE0_SHIFT 24 +#define RTE_JHASH_BYTE1_SHIFT 16 +#define RTE_JHASH_BYTE2_SHIFT 8 +#define RTE_JHASH_BYTE3_SHIFT 0 +#endif + +#define LOWER8b_MASK rte_le_to_cpu_32(0xff) +#define LOWER16b_MASK rte_le_to_cpu_32(0xffff) +#define LOWER24b_MASK rte_le_to_cpu_32(0xffffff) /** * The most generic version, hashes an arbitrary sequence @@ -95,42 +125,119 @@ extern "C" { static inline uint32_t rte_jhash(const void *key, uint32_t length, uint32_t initval) { - uint32_t a, b, c, len; - const uint8_t *k = (const uint8_t *)key; - const uint32_t *k32 = (const uint32_t *)key; + uint32_t a, b, c; + union { + const void *ptr; + size_t i; + } u; - len = length; - a = b = RTE_JHASH_GOLDEN_RATIO; - c = initval; + /* Set up the internal state */ + a = b = c = RTE_JHASH_GOLDEN_RATIO + ((uint32_t)length) + initval; - while (len >= 12) { - a += k32[0]; - b += k32[1]; - c += k32[2]; + u.ptr = key; - __rte_jhash_mix(a,b,c); + /* Check key alignment. For x86 architecture, first case is always optimal */ + if (!strcmp(RTE_ARCH,"x86_64") || !strcmp(RTE_ARCH,"i686") || (u.i & 0x3) == 0) { + const uint32_t *k = (const uint32_t *)key; - k += (3 * sizeof(uint32_t)), k32 += 3; - len -= (3 * sizeof(uint32_t)); - } + while (length > 12) { + a += k[0]; + b += k[1]; + c += k[2]; - c += length; - switch (len) { - case 11: c += ((uint32_t)k[10] << 24); - case 10: c += ((uint32_t)k[9] << 16); - case 9 : c += ((uint32_t)k[8] << 8); - case 8 : b += ((uint32_t)k[7] << 24); - case 7 : b += ((uint32_t)k[6] << 16); - case 6 : b += ((uint32_t)k[5] << 8); - case 5 : b += k[4]; - case 4 : a += ((uint32_t)k[3] << 24); - case 3 : a += ((uint32_t)k[2] << 16); - case 2 : a += ((uint32_t)k[1] << 8); - case 1 : a += k[0]; - default: break; - }; + __rte_jhash_mix(a, b, c); + + k += 3; + length -= 12; + } + + switch (length) { + case 12: + c += k[2]; b += k[1]; a += k[0]; break; + case 11: + c += k[2] & LOWER24b_MASK; b += k[1]; a += k[0]; break; + case 10: + c += k[2] & LOWER16b_MASK; b += k[1]; a += k[0]; break; + case 9: + c += k[2] & LOWER8b_MASK; b += k[1]; a += k[0]; break; + case 8: + b += k[1]; a += k[0]; break; + case 7: + b += k[1] & LOWER24b_MASK; a += k[0]; break; + case 6: + b += k[1] & LOWER16b_MASK; a += k[0]; break; + case 5: + b += k[1] & LOWER8b_MASK; a += k[0]; break; + case 4: + a += k[0]; break; + case 3: + a += k[0] & LOWER24b_MASK; break; + case 2: + a += k[0] & LOWER16b_MASK; break; + case 1: + a += k[0] & LOWER8b_MASK; break; + /* zero length strings require no mixing */ + case 0: + return c; + }; + } else { + const uint8_t *k = (const uint8_t *)key; + + /* all but the last block: affect some 32 bits of (a, b, c) */ + while (length > 12) { + a += ((uint32_t)k[0]) << RTE_JHASH_BYTE0_SHIFT; + a += ((uint32_t)k[1]) << RTE_JHASH_BYTE1_SHIFT; + a += ((uint32_t)k[2]) << RTE_JHASH_BYTE2_SHIFT; + a += ((uint32_t)k[3]) << RTE_JHASH_BYTE3_SHIFT; + b += ((uint32_t)k[4]) << RTE_JHASH_BYTE0_SHIFT; + b += ((uint32_t)k[5]) << RTE_JHASH_BYTE1_SHIFT; + b += ((uint32_t)k[6]) << RTE_JHASH_BYTE2_SHIFT; + b += ((uint32_t)k[7]) << RTE_JHASH_BYTE3_SHIFT; + c += ((uint32_t)k[8]) << RTE_JHASH_BYTE0_SHIFT; + c += ((uint32_t)k[9]) << RTE_JHASH_BYTE1_SHIFT; + c += ((uint32_t)k[10]) << RTE_JHASH_BYTE2_SHIFT; + c += ((uint32_t)k[11]) << RTE_JHASH_BYTE3_SHIFT; - __rte_jhash_mix(a,b,c); + __rte_jhash_mix(a, b, c); + + k += 12; + length -= 12; + } + + /* last block: affect all 32 bits of (c) */ + /* all the case statements fall through */ + switch (length) { + case 12: + c += ((uint32_t)k[11]) << RTE_JHASH_BYTE3_SHIFT; + case 11: + c += ((uint32_t)k[10]) << RTE_JHASH_BYTE2_SHIFT; + case 10: + c += ((uint32_t)k[9]) << RTE_JHASH_BYTE1_SHIFT; + case 9: + c += ((uint32_t)k[8]) << RTE_JHASH_BYTE0_SHIFT; + case 8: + b += ((uint32_t)k[7]) << RTE_JHASH_BYTE3_SHIFT; + case 7: + b += ((uint32_t)k[6]) << RTE_JHASH_BYTE2_SHIFT; + case 6: + b += ((uint32_t)k[5]) << RTE_JHASH_BYTE1_SHIFT; + case 5: + b += ((uint32_t)k[4]) << RTE_JHASH_BYTE0_SHIFT; + case 4: + a += ((uint32_t)k[3]) << RTE_JHASH_BYTE3_SHIFT; + case 3: + a += ((uint32_t)k[2]) << RTE_JHASH_BYTE2_SHIFT; + case 2: + a += ((uint32_t)k[1]) << RTE_JHASH_BYTE1_SHIFT; + case 1: + a += ((uint32_t)k[0]) << RTE_JHASH_BYTE0_SHIFT; + break; + case 0: + return c; + } + } + + __rte_jhash_final(a, b, c); return c; } @@ -151,30 +258,37 @@ rte_jhash(const void *key, uint32_t length, uint32_t initval) static inline uint32_t rte_jhash2(const uint32_t *k, uint32_t length, uint32_t initval) { - uint32_t a, b, c, len; + uint32_t a, b, c; - a = b = RTE_JHASH_GOLDEN_RATIO; - c = initval; - len = length; + /* Set up the internal state */ + a = b = c = RTE_JHASH_GOLDEN_RATIO + (((uint32_t)length) << 2) + initval; - while (len >= 3) { + /* Handle most of the key */ + while (length > 3) { a += k[0]; b += k[1]; c += k[2]; + __rte_jhash_mix(a, b, c); - k += 3; len -= 3; - } - c += length * 4; + k += 3; + length -= 3; + } - switch (len) { - case 2 : b += k[1]; - case 1 : a += k[0]; - default: break; + /* Handle the last 3 uint32_t's */ + switch (length) { + case 3: + c += k[2]; + case 2: + b += k[1]; + case 1: + a += k[0]; + __rte_jhash_final(a, b, c); + /* case 0: nothing left to add */ + case 0: + break; }; - __rte_jhash_mix(a,b,c); - return c; } -- 1.7.4.1