[PATCH v6] hash: add XOR32 hash function

[Thomas Monjalon]

Any review please?
This patch is dying...


21/02/2023 20:37, Bili Dong:
> An XOR32 hash is needed in the Software Switch (SWX) Pipeline for its
> use case in P4. We implement it in this patch so it could be easily
> registered in the pipeline later.
> 
> Signed-off-by: Bili Dong <qobilidop at gmail.com>
> ---
>  .mailmap                       |  1 +
>  app/test/test_hash_functions.c | 33 +++++++++++--
>  lib/hash/rte_hash_xor.h        | 87 ++++++++++++++++++++++++++++++++++
>  3 files changed, 118 insertions(+), 3 deletions(-)
>  create mode 100644 lib/hash/rte_hash_xor.h
> 
> diff --git a/.mailmap b/.mailmap
> index a9f4f28fba..3e9bec29d5 100644
> --- a/.mailmap
> +++ b/.mailmap
> @@ -159,6 +159,7 @@ Bernard Iremonger <bernard.iremonger at intel.com>
>  Bert van Leeuwen <bert.vanleeuwen at netronome.com>
>  Bhagyada Modali <bhagyada.modali at amd.com>
>  Bharat Mota <bmota at vmware.com>
> +Bili Dong <qobilidop at gmail.com>
>  Bill Hong <bhong at brocade.com>
>  Billy McFall <bmcfall at redhat.com>
>  Billy O'Mahony <billy.o.mahony at intel.com>
> diff --git a/app/test/test_hash_functions.c b/app/test/test_hash_functions.c
> index 76d51b6e71..53e296fec4 100644
> --- a/app/test/test_hash_functions.c
> +++ b/app/test/test_hash_functions.c
> @@ -15,6 +15,7 @@
>  #include <rte_hash.h>
>  #include <rte_jhash.h>
>  #include <rte_hash_crc.h>
> +#include <rte_hash_xor.h>
>  
>  #include "test.h"
>  
> @@ -22,8 +23,8 @@
>   * Hash values calculated for key sizes from array "hashtest_key_lens"
>   * and for initial values from array "hashtest_initvals.
>   * Each key will be formed by increasing each byte by 1:
> - * e.g.: key size = 4, key = 0x03020100
> - *       key size = 8, key = 0x0706050403020100
> + * e.g.: key size = 4, key = 0x00010203
> + *       key size = 8, key = 0x0001020304050607
>   */
>  static uint32_t hash_values_jhash[2][12] = {{
>  	0x8ba9414b, 0xdf0d39c9,
> @@ -51,6 +52,19 @@ static uint32_t hash_values_crc[2][12] = {{
>  	0x789c104f, 0x53028d3e
>  }
>  };
> +static uint32_t hash_values_xor32[2][12] = {{
> +	0x00000000, 0x00010000,
> +	0x00010203, 0x04040404, 0x00000000, 0x00000000,
> +	0x00000000, 0x00000000, 0x0c040404, 0x000d0e0f,
> +	0x04212223, 0x04040404
> +},
> +{
> +	0xdeadbeef, 0xdeacbeef,
> +	0xdeacbcec, 0xdaa9baeb, 0xdeadbeef, 0xdeadbeef,
> +	0xdeadbeef, 0xdeadbeef, 0xd2a9baeb, 0xdea0b0e0,
> +	0xda8c9ccc, 0xdaa9baeb
> +}
> +};
>  
>  /*******************************************************************************
>   * Hash function performance test configuration section. Each performance test
> @@ -61,7 +75,7 @@ static uint32_t hash_values_crc[2][12] = {{
>   */
>  #define HASHTEST_ITERATIONS 1000000
>  #define MAX_KEYSIZE 64
> -static rte_hash_function hashtest_funcs[] = {rte_jhash, rte_hash_crc};
> +static rte_hash_function hashtest_funcs[] = {rte_jhash, rte_hash_crc, rte_hash_xor32};
>  static uint32_t hashtest_initvals[] = {0, 0xdeadbeef};
>  static uint32_t hashtest_key_lens[] = {
>  	1, 2,                 /* Unusual key sizes */
> @@ -85,6 +99,9 @@ get_hash_name(rte_hash_function f)
>  	if (f == rte_hash_crc)
>  		return "rte_hash_crc";
>  
> +	if (f == rte_hash_xor32)
> +		return "rte_hash_xor32";
> +
>  	return "UnknownHash";
>  }
>  
> @@ -173,6 +190,16 @@ verify_precalculated_hash_func_tests(void)
>  				       hash_values_crc[j][i], hash);
>  				return -1;
>  			}
> +
> +			hash = rte_hash_xor32(key, hashtest_key_lens[i],
> +					hashtest_initvals[j]);
> +			if (hash != hash_values_xor32[j][i]) {
> +				printf("XOR32 for %u bytes with initial value 0x%x."
> +				       " Expected 0x%x, but got 0x%x\n",
> +				       hashtest_key_lens[i], hashtest_initvals[j],
> +				       hash_values_xor32[j][i], hash);
> +				return -1;
> +			}
>  		}
>  	}
>  
> diff --git a/lib/hash/rte_hash_xor.h b/lib/hash/rte_hash_xor.h
> new file mode 100644
> index 0000000000..366adbe64c
> --- /dev/null
> +++ b/lib/hash/rte_hash_xor.h
> @@ -0,0 +1,87 @@
> +/* SPDX-License-Identifier: BSD-3-Clause
> + * Copyright(c) 2023 Intel Corporation
> + */
> +
> +#ifndef _RTE_HASH_XOR_H_
> +#define _RTE_HASH_XOR_H_
> +
> +/**
> + * @file
> + *
> + * RTE XOR Hash
> + */
> +
> +#ifdef __cplusplus
> +extern "C" {
> +#endif
> +
> +#include <stdint.h>
> +
> +#include <rte_byteorder.h>
> +
> +/**
> + * Calculate XOR32 hash on user-supplied byte array.
> + *
> + * @param data
> + *   Data to perform hash on.
> + * @param data_len
> + *   How many bytes to use to calculate hash value.
> + * @param init_val
> + *   Value to initialise hash generator.
> + * @return
> + *   32bit calculated hash value.
> + */
> +static inline uint32_t
> +rte_hash_xor32(const void *data, uint32_t data_len, uint32_t init_val)
> +{
> +	uint32_t hash32;
> +	const uint8_t *data8 = data;
> +
> +	/* Minimize byte order conversions depending on data length. */
> +	if (data_len >= 8) {
> +		/* For longer arrays, operate in big endian. */
> +		uint64_t hash64 = rte_cpu_to_be_32(init_val);
> +
> +		uint32_t i;
> +		for (i = 0; i < data_len / 8; i++) {
> +			hash64 ^= *(const uint64_t *)data8;
> +			data8 += 8;
> +		}
> +
> +		if (data_len & 0x4) {
> +			hash64 ^= *(const uint32_t *)data8;
> +			data8 += 4;
> +		}
> +
> +		hash32 = rte_be_to_cpu_32(hash64 ^ (hash64 >> 32));
> +	} else {
> +		/* For shorter arrays, operate in host endian. */
> +		hash32 = init_val;
> +
> +		if (data_len & 0x4) {
> +			hash32 ^= rte_be_to_cpu_32(*(const uint32_t *)data8);
> +			data8 += 4;
> +		}
> +	}
> +
> +	/* Deal with remaining (< 4) bytes. */
> +
> +	uint8_t bit_offset = 0;
> +
> +	if (data_len & 0x2) {
> +		hash32 ^= (uint32_t)rte_be_to_cpu_16(*(const uint16_t *)data8) << 16;
> +		data8 += 2;
> +		bit_offset += 16;
> +	}
> +
> +	if (data_len & 0x1)
> +		hash32 ^= (uint32_t)(*(const uint8_t *)data8) << (24 - bit_offset);
> +
> +	return hash32;
> +}
> +
> +#ifdef __cplusplus
> +}
> +#endif
> +
> +#endif /* _RTE_HASH_XOR_H_ */
>