1 /* 2 * Implement fast Fletcher4 with AVX2 instructions. (x86_64) 3 * 4 * Use the 256-bit AVX2 SIMD instructions and registers to compute 5 * Fletcher4 in four incremental 64-bit parallel accumulator streams, 6 * and then combine the streams to form the final four checksum words. 7 * 8 * Copyright (C) 2015 Intel Corporation. 9 * 10 * Authors: 11 * James Guilford <james.guilford@intel.com> 12 * Jinshan Xiong <jinshan.xiong@intel.com> 13 * 14 * This software is available to you under a choice of one of two 15 * licenses. You may choose to be licensed under the terms of the GNU 16 * General Public License (GPL) Version 2, available from the file 17 * COPYING in the main directory of this source tree, or the 18 * OpenIB.org BSD license below: 19 * 20 * Redistribution and use in source and binary forms, with or 21 * without modification, are permitted provided that the following 22 * conditions are met: 23 * 24 * - Redistributions of source code must retain the above 25 * copyright notice, this list of conditions and the following 26 * disclaimer. 27 * 28 * - Redistributions in binary form must reproduce the above 29 * copyright notice, this list of conditions and the following 30 * disclaimer in the documentation and/or other materials 31 * provided with the distribution. 32 * 33 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 34 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 35 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 36 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS 37 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN 38 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 39 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 40 * SOFTWARE. 41 */ 42 43 #if defined(HAVE_AVX) && defined(HAVE_AVX2) 44 45 #include <sys/spa_checksum.h> 46 #include <sys/string.h> 47 #include <sys/simd.h> 48 #include <zfs_fletcher.h> 49 50 ZFS_NO_SANITIZE_UNDEFINED 51 static void 52 fletcher_4_avx2_init(fletcher_4_ctx_t *ctx) 53 { 54 kfpu_begin(); 55 memset(ctx->avx, 0, 4 * sizeof (zfs_fletcher_avx_t)); 56 } 57 58 ZFS_NO_SANITIZE_UNDEFINED 59 static void 60 fletcher_4_avx2_fini(fletcher_4_ctx_t *ctx, zio_cksum_t *zcp) 61 { 62 uint64_t A, B, C, D; 63 64 A = ctx->avx[0].v[0] + ctx->avx[0].v[1] + 65 ctx->avx[0].v[2] + ctx->avx[0].v[3]; 66 B = 0 - ctx->avx[0].v[1] - 2 * ctx->avx[0].v[2] - 3 * ctx->avx[0].v[3] + 67 4 * ctx->avx[1].v[0] + 4 * ctx->avx[1].v[1] + 4 * ctx->avx[1].v[2] + 68 4 * ctx->avx[1].v[3]; 69 70 C = ctx->avx[0].v[2] + 3 * ctx->avx[0].v[3] - 6 * ctx->avx[1].v[0] - 71 10 * ctx->avx[1].v[1] - 14 * ctx->avx[1].v[2] - 72 18 * ctx->avx[1].v[3] + 16 * ctx->avx[2].v[0] + 73 16 * ctx->avx[2].v[1] + 16 * ctx->avx[2].v[2] + 74 16 * ctx->avx[2].v[3]; 75 76 D = 0 - ctx->avx[0].v[3] + 4 * ctx->avx[1].v[0] + 77 10 * ctx->avx[1].v[1] + 20 * ctx->avx[1].v[2] + 78 34 * ctx->avx[1].v[3] - 48 * ctx->avx[2].v[0] - 79 64 * ctx->avx[2].v[1] - 80 * ctx->avx[2].v[2] - 80 96 * ctx->avx[2].v[3] + 64 * ctx->avx[3].v[0] + 81 64 * ctx->avx[3].v[1] + 64 * ctx->avx[3].v[2] + 82 64 * ctx->avx[3].v[3]; 83 84 ZIO_SET_CHECKSUM(zcp, A, B, C, D); 85 kfpu_end(); 86 } 87 88 #define FLETCHER_4_AVX2_RESTORE_CTX(ctx) \ 89 { \ 90 asm volatile("vmovdqu %0, %%ymm0" :: "m" ((ctx)->avx[0])); \ 91 asm volatile("vmovdqu %0, %%ymm1" :: "m" ((ctx)->avx[1])); \ 92 asm volatile("vmovdqu %0, %%ymm2" :: "m" ((ctx)->avx[2])); \ 93 asm volatile("vmovdqu %0, %%ymm3" :: "m" ((ctx)->avx[3])); \ 94 } 95 96 #define FLETCHER_4_AVX2_SAVE_CTX(ctx) \ 97 { \ 98 asm volatile("vmovdqu %%ymm0, %0" : "=m" ((ctx)->avx[0])); \ 99 asm volatile("vmovdqu %%ymm1, %0" : "=m" ((ctx)->avx[1])); \ 100 asm volatile("vmovdqu %%ymm2, %0" : "=m" ((ctx)->avx[2])); \ 101 asm volatile("vmovdqu %%ymm3, %0" : "=m" ((ctx)->avx[3])); \ 102 } 103 104 105 static void 106 fletcher_4_avx2_native(fletcher_4_ctx_t *ctx, const void *buf, uint64_t size) 107 { 108 const uint64_t *ip = buf; 109 const uint64_t *ipend = (uint64_t *)((uint8_t *)ip + size); 110 111 FLETCHER_4_AVX2_RESTORE_CTX(ctx); 112 113 do { 114 asm volatile("vpmovzxdq %0, %%ymm4"::"m" (*ip)); 115 asm volatile("vpaddq %ymm4, %ymm0, %ymm0"); 116 asm volatile("vpaddq %ymm0, %ymm1, %ymm1"); 117 asm volatile("vpaddq %ymm1, %ymm2, %ymm2"); 118 asm volatile("vpaddq %ymm2, %ymm3, %ymm3"); 119 } while ((ip += 2) < ipend); 120 121 FLETCHER_4_AVX2_SAVE_CTX(ctx); 122 asm volatile("vzeroupper"); 123 } 124 125 static void 126 fletcher_4_avx2_byteswap(fletcher_4_ctx_t *ctx, const void *buf, uint64_t size) 127 { 128 static const zfs_fletcher_avx_t mask = { 129 .v = { 0xFFFFFFFF00010203, 0xFFFFFFFF08090A0B, 130 0xFFFFFFFF00010203, 0xFFFFFFFF08090A0B } 131 }; 132 const uint64_t *ip = buf; 133 const uint64_t *ipend = (uint64_t *)((uint8_t *)ip + size); 134 135 FLETCHER_4_AVX2_RESTORE_CTX(ctx); 136 137 asm volatile("vmovdqu %0, %%ymm5" :: "m" (mask)); 138 139 do { 140 asm volatile("vpmovzxdq %0, %%ymm4"::"m" (*ip)); 141 asm volatile("vpshufb %ymm5, %ymm4, %ymm4"); 142 143 asm volatile("vpaddq %ymm4, %ymm0, %ymm0"); 144 asm volatile("vpaddq %ymm0, %ymm1, %ymm1"); 145 asm volatile("vpaddq %ymm1, %ymm2, %ymm2"); 146 asm volatile("vpaddq %ymm2, %ymm3, %ymm3"); 147 } while ((ip += 2) < ipend); 148 149 FLETCHER_4_AVX2_SAVE_CTX(ctx); 150 asm volatile("vzeroupper"); 151 } 152 153 static boolean_t fletcher_4_avx2_valid(void) 154 { 155 return (kfpu_allowed() && zfs_avx_available() && zfs_avx2_available()); 156 } 157 158 const fletcher_4_ops_t fletcher_4_avx2_ops = { 159 .init_native = fletcher_4_avx2_init, 160 .fini_native = fletcher_4_avx2_fini, 161 .compute_native = fletcher_4_avx2_native, 162 .init_byteswap = fletcher_4_avx2_init, 163 .fini_byteswap = fletcher_4_avx2_fini, 164 .compute_byteswap = fletcher_4_avx2_byteswap, 165 .valid = fletcher_4_avx2_valid, 166 .name = "avx2" 167 }; 168 169 #endif /* defined(HAVE_AVX) && defined(HAVE_AVX2) */ 170