1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright 2009 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 * Copyright (C) 2016 Gvozden Nešković. All rights reserved. 25 */ 26 /* 27 * Copyright 2013 Saso Kiselkov. All rights reserved. 28 */ 29 30 /* 31 * Copyright (c) 2016 by Delphix. All rights reserved. 32 */ 33 34 /* 35 * Fletcher Checksums 36 * ------------------ 37 * 38 * ZFS's 2nd and 4th order Fletcher checksums are defined by the following 39 * recurrence relations: 40 * 41 * a = a + f 42 * i i-1 i-1 43 * 44 * b = b + a 45 * i i-1 i 46 * 47 * c = c + b (fletcher-4 only) 48 * i i-1 i 49 * 50 * d = d + c (fletcher-4 only) 51 * i i-1 i 52 * 53 * Where 54 * a_0 = b_0 = c_0 = d_0 = 0 55 * and 56 * f_0 .. f_(n-1) are the input data. 57 * 58 * Using standard techniques, these translate into the following series: 59 * 60 * __n_ __n_ 61 * \ | \ | 62 * a = > f b = > i * f 63 * n /___| n - i n /___| n - i 64 * i = 1 i = 1 65 * 66 * 67 * __n_ __n_ 68 * \ | i*(i+1) \ | i*(i+1)*(i+2) 69 * c = > ------- f d = > ------------- f 70 * n /___| 2 n - i n /___| 6 n - i 71 * i = 1 i = 1 72 * 73 * For fletcher-2, the f_is are 64-bit, and [ab]_i are 64-bit accumulators. 74 * Since the additions are done mod (2^64), errors in the high bits may not 75 * be noticed. For this reason, fletcher-2 is deprecated. 76 * 77 * For fletcher-4, the f_is are 32-bit, and [abcd]_i are 64-bit accumulators. 78 * A conservative estimate of how big the buffer can get before we overflow 79 * can be estimated using f_i = 0xffffffff for all i: 80 * 81 * % bc 82 * f=2^32-1;d=0; for (i = 1; d<2^64; i++) { d += f*i*(i+1)*(i+2)/6 }; (i-1)*4 83 * 2264 84 * quit 85 * % 86 * 87 * So blocks of up to 2k will not overflow. Our largest block size is 88 * 128k, which has 32k 4-byte words, so we can compute the largest possible 89 * accumulators, then divide by 2^64 to figure the max amount of overflow: 90 * 91 * % bc 92 * a=b=c=d=0; f=2^32-1; for (i=1; i<=32*1024; i++) { a+=f; b+=a; c+=b; d+=c } 93 * a/2^64;b/2^64;c/2^64;d/2^64 94 * 0 95 * 0 96 * 1365 97 * 11186858 98 * quit 99 * % 100 * 101 * So a and b cannot overflow. To make sure each bit of input has some 102 * effect on the contents of c and d, we can look at what the factors of 103 * the coefficients in the equations for c_n and d_n are. The number of 2s 104 * in the factors determines the lowest set bit in the multiplier. Running 105 * through the cases for n*(n+1)/2 reveals that the highest power of 2 is 106 * 2^14, and for n*(n+1)*(n+2)/6 it is 2^15. So while some data may overflow 107 * the 64-bit accumulators, every bit of every f_i effects every accumulator, 108 * even for 128k blocks. 109 * 110 * If we wanted to make a stronger version of fletcher4 (fletcher4c?), 111 * we could do our calculations mod (2^32 - 1) by adding in the carries 112 * periodically, and store the number of carries in the top 32-bits. 113 * 114 * -------------------- 115 * Checksum Performance 116 * -------------------- 117 * 118 * There are two interesting components to checksum performance: cached and 119 * uncached performance. With cached data, fletcher-2 is about four times 120 * faster than fletcher-4. With uncached data, the performance difference is 121 * negligible, since the cost of a cache fill dominates the processing time. 122 * Even though fletcher-4 is slower than fletcher-2, it is still a pretty 123 * efficient pass over the data. 124 * 125 * In normal operation, the data which is being checksummed is in a buffer 126 * which has been filled either by: 127 * 128 * 1. a compression step, which will be mostly cached, or 129 * 2. a bcopy() or copyin(), which will be uncached (because the 130 * copy is cache-bypassing). 131 * 132 * For both cached and uncached data, both fletcher checksums are much faster 133 * than sha-256, and slower than 'off', which doesn't touch the data at all. 134 */ 135 136 #include <sys/types.h> 137 #include <sys/sysmacros.h> 138 #include <sys/byteorder.h> 139 #include <sys/spa.h> 140 #include <sys/simd.h> 141 #include <sys/zio_checksum.h> 142 #include <sys/zfs_context.h> 143 #include <zfs_fletcher.h> 144 145 #define FLETCHER_MIN_SIMD_SIZE 64 146 147 static void fletcher_4_scalar_init(fletcher_4_ctx_t *ctx); 148 static void fletcher_4_scalar_fini(fletcher_4_ctx_t *ctx, zio_cksum_t *zcp); 149 static void fletcher_4_scalar_native(fletcher_4_ctx_t *ctx, 150 const void *buf, uint64_t size); 151 static void fletcher_4_scalar_byteswap(fletcher_4_ctx_t *ctx, 152 const void *buf, uint64_t size); 153 static boolean_t fletcher_4_scalar_valid(void); 154 155 static const fletcher_4_ops_t fletcher_4_scalar_ops = { 156 .init_native = fletcher_4_scalar_init, 157 .fini_native = fletcher_4_scalar_fini, 158 .compute_native = fletcher_4_scalar_native, 159 .init_byteswap = fletcher_4_scalar_init, 160 .fini_byteswap = fletcher_4_scalar_fini, 161 .compute_byteswap = fletcher_4_scalar_byteswap, 162 .valid = fletcher_4_scalar_valid, 163 .name = "scalar" 164 }; 165 166 static fletcher_4_ops_t fletcher_4_fastest_impl = { 167 .name = "fastest", 168 .valid = fletcher_4_scalar_valid 169 }; 170 171 static const fletcher_4_ops_t *fletcher_4_impls[] = { 172 &fletcher_4_scalar_ops, 173 &fletcher_4_superscalar_ops, 174 &fletcher_4_superscalar4_ops, 175 #if defined(HAVE_SSE2) 176 &fletcher_4_sse2_ops, 177 #endif 178 #if defined(HAVE_SSE2) && defined(HAVE_SSSE3) 179 &fletcher_4_ssse3_ops, 180 #endif 181 #if defined(HAVE_AVX) && defined(HAVE_AVX2) 182 &fletcher_4_avx2_ops, 183 #endif 184 #if defined(__x86_64) && defined(HAVE_AVX512F) 185 &fletcher_4_avx512f_ops, 186 #endif 187 #if defined(__x86_64) && defined(HAVE_AVX512BW) 188 &fletcher_4_avx512bw_ops, 189 #endif 190 #if defined(__aarch64__) && !defined(__FreeBSD__) 191 &fletcher_4_aarch64_neon_ops, 192 #endif 193 }; 194 195 /* Hold all supported implementations */ 196 static uint32_t fletcher_4_supp_impls_cnt = 0; 197 static fletcher_4_ops_t *fletcher_4_supp_impls[ARRAY_SIZE(fletcher_4_impls)]; 198 199 /* Select fletcher4 implementation */ 200 #define IMPL_FASTEST (UINT32_MAX) 201 #define IMPL_CYCLE (UINT32_MAX - 1) 202 #define IMPL_SCALAR (0) 203 204 static uint32_t fletcher_4_impl_chosen = IMPL_FASTEST; 205 206 #define IMPL_READ(i) (*(volatile uint32_t *) &(i)) 207 208 static struct fletcher_4_impl_selector { 209 const char *fis_name; 210 uint32_t fis_sel; 211 } fletcher_4_impl_selectors[] = { 212 { "cycle", IMPL_CYCLE }, 213 { "fastest", IMPL_FASTEST }, 214 { "scalar", IMPL_SCALAR } 215 }; 216 217 #if defined(_KERNEL) 218 static kstat_t *fletcher_4_kstat; 219 220 static struct fletcher_4_kstat { 221 uint64_t native; 222 uint64_t byteswap; 223 } fletcher_4_stat_data[ARRAY_SIZE(fletcher_4_impls) + 1]; 224 #endif 225 226 /* Indicate that benchmark has been completed */ 227 static boolean_t fletcher_4_initialized = B_FALSE; 228 229 /*ARGSUSED*/ 230 void 231 fletcher_init(zio_cksum_t *zcp) 232 { 233 ZIO_SET_CHECKSUM(zcp, 0, 0, 0, 0); 234 } 235 236 int 237 fletcher_2_incremental_native(void *buf, size_t size, void *data) 238 { 239 zio_cksum_t *zcp = data; 240 241 const uint64_t *ip = buf; 242 const uint64_t *ipend = ip + (size / sizeof (uint64_t)); 243 uint64_t a0, b0, a1, b1; 244 245 a0 = zcp->zc_word[0]; 246 a1 = zcp->zc_word[1]; 247 b0 = zcp->zc_word[2]; 248 b1 = zcp->zc_word[3]; 249 250 for (; ip < ipend; ip += 2) { 251 a0 += ip[0]; 252 a1 += ip[1]; 253 b0 += a0; 254 b1 += a1; 255 } 256 257 ZIO_SET_CHECKSUM(zcp, a0, a1, b0, b1); 258 return (0); 259 } 260 261 /*ARGSUSED*/ 262 void 263 fletcher_2_native(const void *buf, uint64_t size, 264 const void *ctx_template, zio_cksum_t *zcp) 265 { 266 fletcher_init(zcp); 267 (void) fletcher_2_incremental_native((void *) buf, size, zcp); 268 } 269 270 int 271 fletcher_2_incremental_byteswap(void *buf, size_t size, void *data) 272 { 273 zio_cksum_t *zcp = data; 274 275 const uint64_t *ip = buf; 276 const uint64_t *ipend = ip + (size / sizeof (uint64_t)); 277 uint64_t a0, b0, a1, b1; 278 279 a0 = zcp->zc_word[0]; 280 a1 = zcp->zc_word[1]; 281 b0 = zcp->zc_word[2]; 282 b1 = zcp->zc_word[3]; 283 284 for (; ip < ipend; ip += 2) { 285 a0 += BSWAP_64(ip[0]); 286 a1 += BSWAP_64(ip[1]); 287 b0 += a0; 288 b1 += a1; 289 } 290 291 ZIO_SET_CHECKSUM(zcp, a0, a1, b0, b1); 292 return (0); 293 } 294 295 /*ARGSUSED*/ 296 void 297 fletcher_2_byteswap(const void *buf, uint64_t size, 298 const void *ctx_template, zio_cksum_t *zcp) 299 { 300 fletcher_init(zcp); 301 (void) fletcher_2_incremental_byteswap((void *) buf, size, zcp); 302 } 303 304 static void 305 fletcher_4_scalar_init(fletcher_4_ctx_t *ctx) 306 { 307 ZIO_SET_CHECKSUM(&ctx->scalar, 0, 0, 0, 0); 308 } 309 310 static void 311 fletcher_4_scalar_fini(fletcher_4_ctx_t *ctx, zio_cksum_t *zcp) 312 { 313 memcpy(zcp, &ctx->scalar, sizeof (zio_cksum_t)); 314 } 315 316 static void 317 fletcher_4_scalar_native(fletcher_4_ctx_t *ctx, const void *buf, 318 uint64_t size) 319 { 320 const uint32_t *ip = buf; 321 const uint32_t *ipend = ip + (size / sizeof (uint32_t)); 322 uint64_t a, b, c, d; 323 324 a = ctx->scalar.zc_word[0]; 325 b = ctx->scalar.zc_word[1]; 326 c = ctx->scalar.zc_word[2]; 327 d = ctx->scalar.zc_word[3]; 328 329 for (; ip < ipend; ip++) { 330 a += ip[0]; 331 b += a; 332 c += b; 333 d += c; 334 } 335 336 ZIO_SET_CHECKSUM(&ctx->scalar, a, b, c, d); 337 } 338 339 static void 340 fletcher_4_scalar_byteswap(fletcher_4_ctx_t *ctx, const void *buf, 341 uint64_t size) 342 { 343 const uint32_t *ip = buf; 344 const uint32_t *ipend = ip + (size / sizeof (uint32_t)); 345 uint64_t a, b, c, d; 346 347 a = ctx->scalar.zc_word[0]; 348 b = ctx->scalar.zc_word[1]; 349 c = ctx->scalar.zc_word[2]; 350 d = ctx->scalar.zc_word[3]; 351 352 for (; ip < ipend; ip++) { 353 a += BSWAP_32(ip[0]); 354 b += a; 355 c += b; 356 d += c; 357 } 358 359 ZIO_SET_CHECKSUM(&ctx->scalar, a, b, c, d); 360 } 361 362 static boolean_t 363 fletcher_4_scalar_valid(void) 364 { 365 return (B_TRUE); 366 } 367 368 int 369 fletcher_4_impl_set(const char *val) 370 { 371 int err = -EINVAL; 372 uint32_t impl = IMPL_READ(fletcher_4_impl_chosen); 373 size_t i, val_len; 374 375 val_len = strlen(val); 376 while ((val_len > 0) && !!isspace(val[val_len-1])) /* trim '\n' */ 377 val_len--; 378 379 /* check mandatory implementations */ 380 for (i = 0; i < ARRAY_SIZE(fletcher_4_impl_selectors); i++) { 381 const char *name = fletcher_4_impl_selectors[i].fis_name; 382 383 if (val_len == strlen(name) && 384 strncmp(val, name, val_len) == 0) { 385 impl = fletcher_4_impl_selectors[i].fis_sel; 386 err = 0; 387 break; 388 } 389 } 390 391 if (err != 0 && fletcher_4_initialized) { 392 /* check all supported implementations */ 393 for (i = 0; i < fletcher_4_supp_impls_cnt; i++) { 394 const char *name = fletcher_4_supp_impls[i]->name; 395 396 if (val_len == strlen(name) && 397 strncmp(val, name, val_len) == 0) { 398 impl = i; 399 err = 0; 400 break; 401 } 402 } 403 } 404 405 if (err == 0) { 406 atomic_swap_32(&fletcher_4_impl_chosen, impl); 407 membar_producer(); 408 } 409 410 return (err); 411 } 412 413 /* 414 * Returns the Fletcher 4 operations for checksums. When a SIMD 415 * implementation is not allowed in the current context, then fallback 416 * to the fastest generic implementation. 417 */ 418 static inline const fletcher_4_ops_t * 419 fletcher_4_impl_get(void) 420 { 421 if (!kfpu_allowed()) 422 return (&fletcher_4_superscalar4_ops); 423 424 const fletcher_4_ops_t *ops = NULL; 425 uint32_t impl = IMPL_READ(fletcher_4_impl_chosen); 426 427 switch (impl) { 428 case IMPL_FASTEST: 429 ASSERT(fletcher_4_initialized); 430 ops = &fletcher_4_fastest_impl; 431 break; 432 case IMPL_CYCLE: 433 /* Cycle through supported implementations */ 434 ASSERT(fletcher_4_initialized); 435 ASSERT3U(fletcher_4_supp_impls_cnt, >, 0); 436 static uint32_t cycle_count = 0; 437 uint32_t idx = (++cycle_count) % fletcher_4_supp_impls_cnt; 438 ops = fletcher_4_supp_impls[idx]; 439 break; 440 default: 441 ASSERT3U(fletcher_4_supp_impls_cnt, >, 0); 442 ASSERT3U(impl, <, fletcher_4_supp_impls_cnt); 443 ops = fletcher_4_supp_impls[impl]; 444 break; 445 } 446 447 ASSERT3P(ops, !=, NULL); 448 449 return (ops); 450 } 451 452 static inline void 453 fletcher_4_native_impl(const void *buf, uint64_t size, zio_cksum_t *zcp) 454 { 455 fletcher_4_ctx_t ctx; 456 const fletcher_4_ops_t *ops = fletcher_4_impl_get(); 457 458 ops->init_native(&ctx); 459 ops->compute_native(&ctx, buf, size); 460 ops->fini_native(&ctx, zcp); 461 } 462 463 /*ARGSUSED*/ 464 void 465 fletcher_4_native(const void *buf, uint64_t size, 466 const void *ctx_template, zio_cksum_t *zcp) 467 { 468 const uint64_t p2size = P2ALIGN(size, FLETCHER_MIN_SIMD_SIZE); 469 470 ASSERT(IS_P2ALIGNED(size, sizeof (uint32_t))); 471 472 if (size == 0 || p2size == 0) { 473 ZIO_SET_CHECKSUM(zcp, 0, 0, 0, 0); 474 475 if (size > 0) 476 fletcher_4_scalar_native((fletcher_4_ctx_t *)zcp, 477 buf, size); 478 } else { 479 fletcher_4_native_impl(buf, p2size, zcp); 480 481 if (p2size < size) 482 fletcher_4_scalar_native((fletcher_4_ctx_t *)zcp, 483 (char *)buf + p2size, size - p2size); 484 } 485 } 486 487 void 488 fletcher_4_native_varsize(const void *buf, uint64_t size, zio_cksum_t *zcp) 489 { 490 ZIO_SET_CHECKSUM(zcp, 0, 0, 0, 0); 491 fletcher_4_scalar_native((fletcher_4_ctx_t *)zcp, buf, size); 492 } 493 494 static inline void 495 fletcher_4_byteswap_impl(const void *buf, uint64_t size, zio_cksum_t *zcp) 496 { 497 fletcher_4_ctx_t ctx; 498 const fletcher_4_ops_t *ops = fletcher_4_impl_get(); 499 500 ops->init_byteswap(&ctx); 501 ops->compute_byteswap(&ctx, buf, size); 502 ops->fini_byteswap(&ctx, zcp); 503 } 504 505 /*ARGSUSED*/ 506 void 507 fletcher_4_byteswap(const void *buf, uint64_t size, 508 const void *ctx_template, zio_cksum_t *zcp) 509 { 510 const uint64_t p2size = P2ALIGN(size, FLETCHER_MIN_SIMD_SIZE); 511 512 ASSERT(IS_P2ALIGNED(size, sizeof (uint32_t))); 513 514 if (size == 0 || p2size == 0) { 515 ZIO_SET_CHECKSUM(zcp, 0, 0, 0, 0); 516 517 if (size > 0) 518 fletcher_4_scalar_byteswap((fletcher_4_ctx_t *)zcp, 519 buf, size); 520 } else { 521 fletcher_4_byteswap_impl(buf, p2size, zcp); 522 523 if (p2size < size) 524 fletcher_4_scalar_byteswap((fletcher_4_ctx_t *)zcp, 525 (char *)buf + p2size, size - p2size); 526 } 527 } 528 529 /* Incremental Fletcher 4 */ 530 531 #define ZFS_FLETCHER_4_INC_MAX_SIZE (8ULL << 20) 532 533 static inline void 534 fletcher_4_incremental_combine(zio_cksum_t *zcp, const uint64_t size, 535 const zio_cksum_t *nzcp) 536 { 537 const uint64_t c1 = size / sizeof (uint32_t); 538 const uint64_t c2 = c1 * (c1 + 1) / 2; 539 const uint64_t c3 = c2 * (c1 + 2) / 3; 540 541 /* 542 * Value of 'c3' overflows on buffer sizes close to 16MiB. For that 543 * reason we split incremental fletcher4 computation of large buffers 544 * to steps of (ZFS_FLETCHER_4_INC_MAX_SIZE) size. 545 */ 546 ASSERT3U(size, <=, ZFS_FLETCHER_4_INC_MAX_SIZE); 547 548 zcp->zc_word[3] += nzcp->zc_word[3] + c1 * zcp->zc_word[2] + 549 c2 * zcp->zc_word[1] + c3 * zcp->zc_word[0]; 550 zcp->zc_word[2] += nzcp->zc_word[2] + c1 * zcp->zc_word[1] + 551 c2 * zcp->zc_word[0]; 552 zcp->zc_word[1] += nzcp->zc_word[1] + c1 * zcp->zc_word[0]; 553 zcp->zc_word[0] += nzcp->zc_word[0]; 554 } 555 556 static inline void 557 fletcher_4_incremental_impl(boolean_t native, const void *buf, uint64_t size, 558 zio_cksum_t *zcp) 559 { 560 while (size > 0) { 561 zio_cksum_t nzc; 562 uint64_t len = MIN(size, ZFS_FLETCHER_4_INC_MAX_SIZE); 563 564 if (native) 565 fletcher_4_native(buf, len, NULL, &nzc); 566 else 567 fletcher_4_byteswap(buf, len, NULL, &nzc); 568 569 fletcher_4_incremental_combine(zcp, len, &nzc); 570 571 size -= len; 572 buf += len; 573 } 574 } 575 576 int 577 fletcher_4_incremental_native(void *buf, size_t size, void *data) 578 { 579 zio_cksum_t *zcp = data; 580 /* Use scalar impl to directly update cksum of small blocks */ 581 if (size < SPA_MINBLOCKSIZE) 582 fletcher_4_scalar_native((fletcher_4_ctx_t *)zcp, buf, size); 583 else 584 fletcher_4_incremental_impl(B_TRUE, buf, size, zcp); 585 return (0); 586 } 587 588 int 589 fletcher_4_incremental_byteswap(void *buf, size_t size, void *data) 590 { 591 zio_cksum_t *zcp = data; 592 /* Use scalar impl to directly update cksum of small blocks */ 593 if (size < SPA_MINBLOCKSIZE) 594 fletcher_4_scalar_byteswap((fletcher_4_ctx_t *)zcp, buf, size); 595 else 596 fletcher_4_incremental_impl(B_FALSE, buf, size, zcp); 597 return (0); 598 } 599 600 #if defined(_KERNEL) 601 /* 602 * Fletcher 4 kstats 603 */ 604 static int 605 fletcher_4_kstat_headers(char *buf, size_t size) 606 { 607 ssize_t off = 0; 608 609 off += snprintf(buf + off, size, "%-17s", "implementation"); 610 off += snprintf(buf + off, size - off, "%-15s", "native"); 611 (void) snprintf(buf + off, size - off, "%-15s\n", "byteswap"); 612 613 return (0); 614 } 615 616 static int 617 fletcher_4_kstat_data(char *buf, size_t size, void *data) 618 { 619 struct fletcher_4_kstat *fastest_stat = 620 &fletcher_4_stat_data[fletcher_4_supp_impls_cnt]; 621 struct fletcher_4_kstat *curr_stat = (struct fletcher_4_kstat *)data; 622 ssize_t off = 0; 623 624 if (curr_stat == fastest_stat) { 625 off += snprintf(buf + off, size - off, "%-17s", "fastest"); 626 off += snprintf(buf + off, size - off, "%-15s", 627 fletcher_4_supp_impls[fastest_stat->native]->name); 628 off += snprintf(buf + off, size - off, "%-15s\n", 629 fletcher_4_supp_impls[fastest_stat->byteswap]->name); 630 } else { 631 ptrdiff_t id = curr_stat - fletcher_4_stat_data; 632 633 off += snprintf(buf + off, size - off, "%-17s", 634 fletcher_4_supp_impls[id]->name); 635 off += snprintf(buf + off, size - off, "%-15llu", 636 (u_longlong_t)curr_stat->native); 637 off += snprintf(buf + off, size - off, "%-15llu\n", 638 (u_longlong_t)curr_stat->byteswap); 639 } 640 641 return (0); 642 } 643 644 static void * 645 fletcher_4_kstat_addr(kstat_t *ksp, loff_t n) 646 { 647 if (n <= fletcher_4_supp_impls_cnt) 648 ksp->ks_private = (void *) (fletcher_4_stat_data + n); 649 else 650 ksp->ks_private = NULL; 651 652 return (ksp->ks_private); 653 } 654 #endif 655 656 #define FLETCHER_4_FASTEST_FN_COPY(type, src) \ 657 { \ 658 fletcher_4_fastest_impl.init_ ## type = src->init_ ## type; \ 659 fletcher_4_fastest_impl.fini_ ## type = src->fini_ ## type; \ 660 fletcher_4_fastest_impl.compute_ ## type = src->compute_ ## type; \ 661 } 662 663 #define FLETCHER_4_BENCH_NS (MSEC2NSEC(1)) /* 1ms */ 664 665 typedef void fletcher_checksum_func_t(const void *, uint64_t, const void *, 666 zio_cksum_t *); 667 668 #if defined(_KERNEL) 669 static void 670 fletcher_4_benchmark_impl(boolean_t native, char *data, uint64_t data_size) 671 { 672 673 struct fletcher_4_kstat *fastest_stat = 674 &fletcher_4_stat_data[fletcher_4_supp_impls_cnt]; 675 hrtime_t start; 676 uint64_t run_bw, run_time_ns, best_run = 0; 677 zio_cksum_t zc; 678 uint32_t i, l, sel_save = IMPL_READ(fletcher_4_impl_chosen); 679 680 fletcher_checksum_func_t *fletcher_4_test = native ? 681 fletcher_4_native : fletcher_4_byteswap; 682 683 for (i = 0; i < fletcher_4_supp_impls_cnt; i++) { 684 struct fletcher_4_kstat *stat = &fletcher_4_stat_data[i]; 685 uint64_t run_count = 0; 686 687 /* temporary set an implementation */ 688 fletcher_4_impl_chosen = i; 689 690 kpreempt_disable(); 691 start = gethrtime(); 692 do { 693 for (l = 0; l < 32; l++, run_count++) 694 fletcher_4_test(data, data_size, NULL, &zc); 695 696 run_time_ns = gethrtime() - start; 697 } while (run_time_ns < FLETCHER_4_BENCH_NS); 698 kpreempt_enable(); 699 700 run_bw = data_size * run_count * NANOSEC; 701 run_bw /= run_time_ns; /* B/s */ 702 703 if (native) 704 stat->native = run_bw; 705 else 706 stat->byteswap = run_bw; 707 708 if (run_bw > best_run) { 709 best_run = run_bw; 710 711 if (native) { 712 fastest_stat->native = i; 713 FLETCHER_4_FASTEST_FN_COPY(native, 714 fletcher_4_supp_impls[i]); 715 } else { 716 fastest_stat->byteswap = i; 717 FLETCHER_4_FASTEST_FN_COPY(byteswap, 718 fletcher_4_supp_impls[i]); 719 } 720 } 721 } 722 723 /* restore original selection */ 724 atomic_swap_32(&fletcher_4_impl_chosen, sel_save); 725 } 726 #endif /* _KERNEL */ 727 728 /* 729 * Initialize and benchmark all supported implementations. 730 */ 731 static void 732 fletcher_4_benchmark(void) 733 { 734 fletcher_4_ops_t *curr_impl; 735 int i, c; 736 737 /* Move supported implementations into fletcher_4_supp_impls */ 738 for (i = 0, c = 0; i < ARRAY_SIZE(fletcher_4_impls); i++) { 739 curr_impl = (fletcher_4_ops_t *)fletcher_4_impls[i]; 740 741 if (curr_impl->valid && curr_impl->valid()) 742 fletcher_4_supp_impls[c++] = curr_impl; 743 } 744 membar_producer(); /* complete fletcher_4_supp_impls[] init */ 745 fletcher_4_supp_impls_cnt = c; /* number of supported impl */ 746 747 #if defined(_KERNEL) 748 static const size_t data_size = 1 << SPA_OLD_MAXBLOCKSHIFT; /* 128kiB */ 749 char *databuf = vmem_alloc(data_size, KM_SLEEP); 750 751 for (i = 0; i < data_size / sizeof (uint64_t); i++) 752 ((uint64_t *)databuf)[i] = (uintptr_t)(databuf+i); /* warm-up */ 753 754 fletcher_4_benchmark_impl(B_FALSE, databuf, data_size); 755 fletcher_4_benchmark_impl(B_TRUE, databuf, data_size); 756 757 vmem_free(databuf, data_size); 758 #else 759 /* 760 * Skip the benchmark in user space to avoid impacting libzpool 761 * consumers (zdb, zhack, zinject, ztest). The last implementation 762 * is assumed to be the fastest and used by default. 763 */ 764 memcpy(&fletcher_4_fastest_impl, 765 fletcher_4_supp_impls[fletcher_4_supp_impls_cnt - 1], 766 sizeof (fletcher_4_fastest_impl)); 767 fletcher_4_fastest_impl.name = "fastest"; 768 membar_producer(); 769 #endif /* _KERNEL */ 770 } 771 772 void 773 fletcher_4_init(void) 774 { 775 /* Determine the fastest available implementation. */ 776 fletcher_4_benchmark(); 777 778 #if defined(_KERNEL) 779 /* Install kstats for all implementations */ 780 fletcher_4_kstat = kstat_create("zfs", 0, "fletcher_4_bench", "misc", 781 KSTAT_TYPE_RAW, 0, KSTAT_FLAG_VIRTUAL); 782 if (fletcher_4_kstat != NULL) { 783 fletcher_4_kstat->ks_data = NULL; 784 fletcher_4_kstat->ks_ndata = UINT32_MAX; 785 kstat_set_raw_ops(fletcher_4_kstat, 786 fletcher_4_kstat_headers, 787 fletcher_4_kstat_data, 788 fletcher_4_kstat_addr); 789 kstat_install(fletcher_4_kstat); 790 } 791 #endif 792 793 /* Finish initialization */ 794 fletcher_4_initialized = B_TRUE; 795 } 796 797 void 798 fletcher_4_fini(void) 799 { 800 #if defined(_KERNEL) 801 if (fletcher_4_kstat != NULL) { 802 kstat_delete(fletcher_4_kstat); 803 fletcher_4_kstat = NULL; 804 } 805 #endif 806 } 807 808 /* ABD adapters */ 809 810 static void 811 abd_fletcher_4_init(zio_abd_checksum_data_t *cdp) 812 { 813 const fletcher_4_ops_t *ops = fletcher_4_impl_get(); 814 cdp->acd_private = (void *) ops; 815 816 if (cdp->acd_byteorder == ZIO_CHECKSUM_NATIVE) 817 ops->init_native(cdp->acd_ctx); 818 else 819 ops->init_byteswap(cdp->acd_ctx); 820 } 821 822 static void 823 abd_fletcher_4_fini(zio_abd_checksum_data_t *cdp) 824 { 825 fletcher_4_ops_t *ops = (fletcher_4_ops_t *)cdp->acd_private; 826 827 ASSERT(ops); 828 829 if (cdp->acd_byteorder == ZIO_CHECKSUM_NATIVE) 830 ops->fini_native(cdp->acd_ctx, cdp->acd_zcp); 831 else 832 ops->fini_byteswap(cdp->acd_ctx, cdp->acd_zcp); 833 } 834 835 static void 836 abd_fletcher_4_simd2scalar(boolean_t native, void *data, size_t size, 837 zio_abd_checksum_data_t *cdp) 838 { 839 zio_cksum_t *zcp = cdp->acd_zcp; 840 841 ASSERT3U(size, <, FLETCHER_MIN_SIMD_SIZE); 842 843 abd_fletcher_4_fini(cdp); 844 cdp->acd_private = (void *)&fletcher_4_scalar_ops; 845 846 if (native) 847 fletcher_4_incremental_native(data, size, zcp); 848 else 849 fletcher_4_incremental_byteswap(data, size, zcp); 850 } 851 852 static int 853 abd_fletcher_4_iter(void *data, size_t size, void *private) 854 { 855 zio_abd_checksum_data_t *cdp = (zio_abd_checksum_data_t *)private; 856 fletcher_4_ctx_t *ctx = cdp->acd_ctx; 857 fletcher_4_ops_t *ops = (fletcher_4_ops_t *)cdp->acd_private; 858 boolean_t native = cdp->acd_byteorder == ZIO_CHECKSUM_NATIVE; 859 uint64_t asize = P2ALIGN(size, FLETCHER_MIN_SIMD_SIZE); 860 861 ASSERT(IS_P2ALIGNED(size, sizeof (uint32_t))); 862 863 if (asize > 0) { 864 if (native) 865 ops->compute_native(ctx, data, asize); 866 else 867 ops->compute_byteswap(ctx, data, asize); 868 869 size -= asize; 870 data = (char *)data + asize; 871 } 872 873 if (size > 0) { 874 ASSERT3U(size, <, FLETCHER_MIN_SIMD_SIZE); 875 /* At this point we have to switch to scalar impl */ 876 abd_fletcher_4_simd2scalar(native, data, size, cdp); 877 } 878 879 return (0); 880 } 881 882 zio_abd_checksum_func_t fletcher_4_abd_ops = { 883 .acf_init = abd_fletcher_4_init, 884 .acf_fini = abd_fletcher_4_fini, 885 .acf_iter = abd_fletcher_4_iter 886 }; 887 888 #if defined(_KERNEL) 889 890 #define IMPL_FMT(impl, i) (((impl) == (i)) ? "[%s] " : "%s ") 891 892 #if defined(__linux__) 893 894 static int 895 fletcher_4_param_get(char *buffer, zfs_kernel_param_t *unused) 896 { 897 const uint32_t impl = IMPL_READ(fletcher_4_impl_chosen); 898 char *fmt; 899 int cnt = 0; 900 901 /* list fastest */ 902 fmt = IMPL_FMT(impl, IMPL_FASTEST); 903 cnt += sprintf(buffer + cnt, fmt, "fastest"); 904 905 /* list all supported implementations */ 906 for (uint32_t i = 0; i < fletcher_4_supp_impls_cnt; ++i) { 907 fmt = IMPL_FMT(impl, i); 908 cnt += sprintf(buffer + cnt, fmt, 909 fletcher_4_supp_impls[i]->name); 910 } 911 912 return (cnt); 913 } 914 915 static int 916 fletcher_4_param_set(const char *val, zfs_kernel_param_t *unused) 917 { 918 return (fletcher_4_impl_set(val)); 919 } 920 921 #else 922 923 #include <sys/sbuf.h> 924 925 static int 926 fletcher_4_param(ZFS_MODULE_PARAM_ARGS) 927 { 928 int err; 929 930 if (req->newptr == NULL) { 931 const uint32_t impl = IMPL_READ(fletcher_4_impl_chosen); 932 const int init_buflen = 64; 933 const char *fmt; 934 struct sbuf *s; 935 936 s = sbuf_new_for_sysctl(NULL, NULL, init_buflen, req); 937 938 /* list fastest */ 939 fmt = IMPL_FMT(impl, IMPL_FASTEST); 940 (void) sbuf_printf(s, fmt, "fastest"); 941 942 /* list all supported implementations */ 943 for (uint32_t i = 0; i < fletcher_4_supp_impls_cnt; ++i) { 944 fmt = IMPL_FMT(impl, i); 945 (void) sbuf_printf(s, fmt, 946 fletcher_4_supp_impls[i]->name); 947 } 948 949 err = sbuf_finish(s); 950 sbuf_delete(s); 951 952 return (err); 953 } 954 955 char buf[16]; 956 957 err = sysctl_handle_string(oidp, buf, sizeof (buf), req); 958 if (err) 959 return (err); 960 return (-fletcher_4_impl_set(buf)); 961 } 962 963 #endif 964 965 #undef IMPL_FMT 966 967 /* 968 * Choose a fletcher 4 implementation in ZFS. 969 * Users can choose "cycle" to exercise all implementations, but this is 970 * for testing purpose therefore it can only be set in user space. 971 */ 972 /* BEGIN CSTYLED */ 973 ZFS_MODULE_VIRTUAL_PARAM_CALL(zfs, zfs_, fletcher_4_impl, 974 fletcher_4_param_set, fletcher_4_param_get, ZMOD_RW, 975 "Select fletcher 4 implementation."); 976 /* END CSTYLED */ 977 978 EXPORT_SYMBOL(fletcher_init); 979 EXPORT_SYMBOL(fletcher_2_incremental_native); 980 EXPORT_SYMBOL(fletcher_2_incremental_byteswap); 981 EXPORT_SYMBOL(fletcher_4_init); 982 EXPORT_SYMBOL(fletcher_4_fini); 983 EXPORT_SYMBOL(fletcher_2_native); 984 EXPORT_SYMBOL(fletcher_2_byteswap); 985 EXPORT_SYMBOL(fletcher_4_native); 986 EXPORT_SYMBOL(fletcher_4_native_varsize); 987 EXPORT_SYMBOL(fletcher_4_byteswap); 988 EXPORT_SYMBOL(fletcher_4_incremental_native); 989 EXPORT_SYMBOL(fletcher_4_incremental_byteswap); 990 EXPORT_SYMBOL(fletcher_4_abd_ops); 991 #endif 992