module/zcommon/zfs_fletcher_sse.c

   1 /*
   2  * Implement fast Fletcher4 with SSE2,SSSE3 instructions. (x86)
   3  *
   4  * Use the 128-bit SSE2/SSSE3 SIMD instructions and registers to compute
   5  * Fletcher4 in two incremental 64-bit parallel accumulator streams,
   6  * and then combine the streams to form the final four checksum words.
   7  * This implementation is a derivative of the AVX SIMD implementation by
   8  * James Guilford and Jinshan Xiong from Intel (see zfs_fletcher_intel.c).
   9  *
  10  * Copyright (C) 2016 Tyler J. Stachecki.
  11  *
  12  * Authors:
  13  *      Tyler J. Stachecki <stachecki.tyler@gmail.com>
  14  *
  15  * This software is available to you under a choice of one of two
  16  * licenses.  You may choose to be licensed under the terms of the GNU
  17  * General Public License (GPL) Version 2, available from the file
  18  * COPYING in the main directory of this source tree, or the
  19  * OpenIB.org BSD license below:
  20  *
  21  *     Redistribution and use in source and binary forms, with or
  22  *     without modification, are permitted provided that the following
  23  *     conditions are met:
  24  *
  25  *      - Redistributions of source code must retain the above
  26  *        copyright notice, this list of conditions and the following
  27  *        disclaimer.
  28  *
  29  *      - Redistributions in binary form must reproduce the above
  30  *        copyright notice, this list of conditions and the following
  31  *        disclaimer in the documentation and/or other materials
  32  *        provided with the distribution.
  33  *
  34  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  35  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  36  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  37  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  38  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  39  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  40  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  41  * SOFTWARE.
  42  */
  43
  44 #if defined(HAVE_SSE2)
  45
  46 #include <linux/simd_x86.h>
  47 #include <sys/spa_checksum.h>
  48 #include <sys/byteorder.h>
  49 #include <sys/strings.h>
  50 #include <zfs_fletcher.h>
  51
  52 static void
  53 fletcher_4_sse2_init(fletcher_4_ctx_t *ctx)
  54 {
  55         bzero(ctx->sse, 4 * sizeof (zfs_fletcher_sse_t));
  56 }
  57
  58 static void
  59 fletcher_4_sse2_fini(fletcher_4_ctx_t *ctx, zio_cksum_t *zcp)
  60 {
  61         uint64_t A, B, C, D;
  62
  63         /*
  64          * The mixing matrix for checksum calculation is:
  65          * a = a0 + a1
  66          * b = 2b0 + 2b1 - a1
  67          * c = 4c0 - b0 + 4c1 -3b1
  68          * d = 8d0 - 4c0 + 8d1 - 8c1 + b1;
  69          *
  70          * c and d are multiplied by 4 and 8, respectively,
  71          * before spilling the vectors out to memory.
  72          */
  73         A = ctx->sse[0].v[0] + ctx->sse[0].v[1];
  74         B = 2 * ctx->sse[1].v[0] + 2 * ctx->sse[1].v[1] - ctx->sse[0].v[1];
  75         C = 4 * ctx->sse[2].v[0] - ctx->sse[1].v[0] + 4 * ctx->sse[2].v[1] -
  76             3 * ctx->sse[1].v[1];
  77         D = 8 * ctx->sse[3].v[0] - 4 * ctx->sse[2].v[0] + 8 * ctx->sse[3].v[1] -
  78             8 * ctx->sse[2].v[1] + ctx->sse[1].v[1];
  79
  80         ZIO_SET_CHECKSUM(zcp, A, B, C, D);
  81 }
  82
  83 #define FLETCHER_4_SSE_RESTORE_CTX(ctx)                                 \
  84 {                                                                       \
  85         asm volatile("movdqu %0, %%xmm0" :: "m" ((ctx)->sse[0]));       \
  86         asm volatile("movdqu %0, %%xmm1" :: "m" ((ctx)->sse[1]));       \
  87         asm volatile("movdqu %0, %%xmm2" :: "m" ((ctx)->sse[2]));       \
  88         asm volatile("movdqu %0, %%xmm3" :: "m" ((ctx)->sse[3]));       \
  89 }
  90
  91 #define FLETCHER_4_SSE_SAVE_CTX(ctx)                                    \
  92 {                                                                       \
  93         asm volatile("movdqu %%xmm0, %0" : "=m" ((ctx)->sse[0]));       \
  94         asm volatile("movdqu %%xmm1, %0" : "=m" ((ctx)->sse[1]));       \
  95         asm volatile("movdqu %%xmm2, %0" : "=m" ((ctx)->sse[2]));       \
  96         asm volatile("movdqu %%xmm3, %0" : "=m" ((ctx)->sse[3]));       \
  97 }
  98
  99 static void
 100 fletcher_4_sse2_native(fletcher_4_ctx_t *ctx, const void *buf, uint64_t size)
 101 {
 102         const uint64_t *ip = buf;
 103         const uint64_t *ipend = (uint64_t *)((uint8_t *)ip + size);
 104
 105         kfpu_begin();
 106
 107         FLETCHER_4_SSE_RESTORE_CTX(ctx);
 108
 109         asm volatile("pxor %xmm4, %xmm4");
 110
 111         for (; ip < ipend; ip += 2) {
 112                 asm volatile("movdqu %0, %%xmm5" :: "m"(*ip));
 113                 asm volatile("movdqa %xmm5, %xmm6");
 114                 asm volatile("punpckldq %xmm4, %xmm5");
 115                 asm volatile("punpckhdq %xmm4, %xmm6");
 116                 asm volatile("paddq %xmm5, %xmm0");
 117                 asm volatile("paddq %xmm0, %xmm1");
 118                 asm volatile("paddq %xmm1, %xmm2");
 119                 asm volatile("paddq %xmm2, %xmm3");
 120                 asm volatile("paddq %xmm6, %xmm0");
 121                 asm volatile("paddq %xmm0, %xmm1");
 122                 asm volatile("paddq %xmm1, %xmm2");
 123                 asm volatile("paddq %xmm2, %xmm3");
 124         }
 125
 126         FLETCHER_4_SSE_SAVE_CTX(ctx);
 127
 128         kfpu_end();
 129 }
 130
 131 static void
 132 fletcher_4_sse2_byteswap(fletcher_4_ctx_t *ctx, const void *buf, uint64_t size)
 133 {
 134         const uint32_t *ip = buf;
 135         const uint32_t *ipend = (uint32_t *)((uint8_t *)ip + size);
 136
 137         kfpu_begin();
 138
 139         FLETCHER_4_SSE_RESTORE_CTX(ctx);
 140
 141         for (; ip < ipend; ip += 2) {
 142                 uint32_t scratch1 = BSWAP_32(ip[0]);
 143                 uint32_t scratch2 = BSWAP_32(ip[1]);
 144                 asm volatile("movd %0, %%xmm5" :: "r"(scratch1));
 145                 asm volatile("movd %0, %%xmm6" :: "r"(scratch2));
 146                 asm volatile("punpcklqdq %xmm6, %xmm5");
 147                 asm volatile("paddq %xmm5, %xmm0");
 148                 asm volatile("paddq %xmm0, %xmm1");
 149                 asm volatile("paddq %xmm1, %xmm2");
 150                 asm volatile("paddq %xmm2, %xmm3");
 151         }
 152
 153         FLETCHER_4_SSE_SAVE_CTX(ctx);
 154
 155         kfpu_end();
 156 }
 157
 158 static boolean_t fletcher_4_sse2_valid(void)
 159 {
 160         return (zfs_sse2_available());
 161 }
 162
 163 const fletcher_4_ops_t fletcher_4_sse2_ops = {
 164         .init_native = fletcher_4_sse2_init,
 165         .fini_native = fletcher_4_sse2_fini,
 166         .compute_native = fletcher_4_sse2_native,
 167         .init_byteswap = fletcher_4_sse2_init,
 168         .fini_byteswap = fletcher_4_sse2_fini,
 169         .compute_byteswap = fletcher_4_sse2_byteswap,
 170         .valid = fletcher_4_sse2_valid,
 171         .name = "sse2"
 172 };
 173
 174 #endif /* defined(HAVE_SSE2) */
 175
 176 #if defined(HAVE_SSE2) && defined(HAVE_SSSE3)
 177 static void
 178 fletcher_4_ssse3_byteswap(fletcher_4_ctx_t *ctx, const void *buf, uint64_t size)
 179 {
 180         static const zfs_fletcher_sse_t mask = {
 181                 .v = { 0x0405060700010203, 0x0C0D0E0F08090A0B }
 182         };
 183
 184         const uint64_t *ip = buf;
 185         const uint64_t *ipend = (uint64_t *)((uint8_t *)ip + size);
 186
 187         kfpu_begin();
 188
 189         FLETCHER_4_SSE_RESTORE_CTX(ctx);
 190
 191         asm volatile("movdqu %0, %%xmm7"::"m" (mask));
 192         asm volatile("pxor %xmm4, %xmm4");
 193
 194         for (; ip < ipend; ip += 2) {
 195                 asm volatile("movdqu %0, %%xmm5"::"m" (*ip));
 196                 asm volatile("pshufb %xmm7, %xmm5");
 197                 asm volatile("movdqa %xmm5, %xmm6");
 198                 asm volatile("punpckldq %xmm4, %xmm5");
 199                 asm volatile("punpckhdq %xmm4, %xmm6");
 200                 asm volatile("paddq %xmm5, %xmm0");
 201                 asm volatile("paddq %xmm0, %xmm1");
 202                 asm volatile("paddq %xmm1, %xmm2");
 203                 asm volatile("paddq %xmm2, %xmm3");
 204                 asm volatile("paddq %xmm6, %xmm0");
 205                 asm volatile("paddq %xmm0, %xmm1");
 206                 asm volatile("paddq %xmm1, %xmm2");
 207                 asm volatile("paddq %xmm2, %xmm3");
 208         }
 209
 210         FLETCHER_4_SSE_SAVE_CTX(ctx);
 211
 212         kfpu_end();
 213 }
 214
 215 static boolean_t fletcher_4_ssse3_valid(void)
 216 {
 217         return (zfs_sse2_available() && zfs_ssse3_available());
 218 }
 219
 220 const fletcher_4_ops_t fletcher_4_ssse3_ops = {
 221         .init_native = fletcher_4_sse2_init,
 222         .fini_native = fletcher_4_sse2_fini,
 223         .compute_native = fletcher_4_sse2_native,
 224         .init_byteswap = fletcher_4_sse2_init,
 225         .fini_byteswap = fletcher_4_sse2_fini,
 226         .compute_byteswap = fletcher_4_ssse3_byteswap,
 227         .valid = fletcher_4_ssse3_valid,
 228         .name = "ssse3"
 229 };
 230
 231 #endif /* defined(HAVE_SSE2) && defined(HAVE_SSSE3) */