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Implementation of SSE optimized Fletcher-4
Builds off of 1eeb456 (Implementation of AVX2 optimized Fletcher-4) This commit adds another implementation of the Fletcher-4 algorithm. It is automatically selected at module load if it benchmarks higher than all other available implementations. The module benchmark was also amended to analyze the performance of the byteswap-ed version of Fletcher-4, as well as the non-byteswaped version. The average performance of the two is used to select the the fastest implementation available on the host system. Adds a pair of fields to an existing zcommon module parameter: - zfs_fletcher_4_impl (str) "sse2" - new SSE2 implementation if available "ssse3" - new SSSE3 implementation if available Signed-off-by: Tyler J. Stachecki <[email protected]> Signed-off-by: Gvozden Neskovic <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes openzfs#4789
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| /* | ||
| * Implement fast Fletcher4 with SSE2,SSSE3 instructions. (x86) | ||
| * | ||
| * Use the 128-bit SSE2/SSSE3 SIMD instructions and registers to compute | ||
| * Fletcher4 in four incremental 64-bit parallel accumulator streams, | ||
| * and then combine the streams to form the final four checksum words. | ||
| * This implementation is a derivative of the AVX SIMD implementation by | ||
| * James Guilford and Jinshan Xiong from Intel (see zfs_fletcher_intel.c). | ||
| * | ||
| * Copyright (C) 2016 Tyler J. Stachecki. | ||
| * | ||
| * Authors: | ||
| * Tyler J. Stachecki <[email protected]> | ||
| * | ||
| * This software is available to you under a choice of one of two | ||
| * licenses. You may choose to be licensed under the terms of the GNU | ||
| * General Public License (GPL) Version 2, available from the file | ||
| * COPYING in the main directory of this source tree, or the | ||
| * OpenIB.org BSD license below: | ||
| * | ||
| * Redistribution and use in source and binary forms, with or | ||
| * without modification, are permitted provided that the following | ||
| * conditions are met: | ||
| * | ||
| * - Redistributions of source code must retain the above | ||
| * copyright notice, this list of conditions and the following | ||
| * disclaimer. | ||
| * | ||
| * - Redistributions in binary form must reproduce the above | ||
| * copyright notice, this list of conditions and the following | ||
| * disclaimer in the documentation and/or other materials | ||
| * provided with the distribution. | ||
| * | ||
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, | ||
| * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF | ||
| * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND | ||
| * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS | ||
| * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN | ||
| * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN | ||
| * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | ||
| * SOFTWARE. | ||
| */ | ||
|
|
||
| #if defined(HAVE_SSE2) | ||
|
|
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| #include <linux/simd_x86.h> | ||
| #include <sys/spa_checksum.h> | ||
| #include <zfs_fletcher.h> | ||
|
|
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| struct zfs_fletcher_sse_array { | ||
| uint64_t v[2] __attribute__((aligned(16))); | ||
| }; | ||
|
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| static void | ||
| fletcher_4_sse2_init(zio_cksum_t *zcp) | ||
| { | ||
| kfpu_begin(); | ||
|
|
||
| /* clear sse registers */ | ||
| asm volatile("pxor %xmm0, %xmm0"); | ||
| asm volatile("pxor %xmm1, %xmm1"); | ||
| asm volatile("pxor %xmm2, %xmm2"); | ||
| asm volatile("pxor %xmm3, %xmm3"); | ||
| } | ||
|
|
||
| static void | ||
| fletcher_4_sse2_fini(zio_cksum_t *zcp) | ||
| { | ||
| struct zfs_fletcher_sse_array a, b, c, d; | ||
| uint64_t A, B, C, D; | ||
|
|
||
| asm volatile("movdqa %%xmm0, %0":"=m" (a.v)); | ||
| asm volatile("movdqa %%xmm1, %0":"=m" (b.v)); | ||
| asm volatile("psllq $0x2, %xmm2"); | ||
| asm volatile("movdqa %%xmm2, %0":"=m" (c.v)); | ||
| asm volatile("psllq $0x3, %xmm3"); | ||
| asm volatile("movdqa %%xmm3, %0":"=m" (d.v)); | ||
|
|
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| kfpu_end(); | ||
|
|
||
| /* | ||
| * The mixing matrix for checksum calculation is: | ||
| * a = a0 + a1 | ||
| * b = 2b0 + 2b1 - a1 | ||
| * c = 4c0 - b0 + 4c1 -3b1 | ||
| * d = 8d0 - 4c0 + 8d1 - 8c1 + b1; | ||
| * | ||
| * c and d are multiplied by 4 and 8, respectively, | ||
| * before spilling the vectors out to memory. | ||
| */ | ||
| A = a.v[0] + a.v[1]; | ||
| B = 2*b.v[0] + 2*b.v[1] - a.v[1]; | ||
| C = c.v[0] - b.v[0] + c.v[1] - 3*b.v[1]; | ||
| D = d.v[0] - c.v[0] + d.v[1] - 2*c.v[1] + b.v[1]; | ||
|
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| ZIO_SET_CHECKSUM(zcp, A, B, C, D); | ||
| } | ||
|
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| static void | ||
| fletcher_4_sse2(const void *buf, uint64_t size, zio_cksum_t *unused) | ||
| { | ||
| const uint64_t *ip = buf; | ||
| const uint64_t *ipend = (uint64_t *)((uint8_t *)ip + size); | ||
|
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| asm volatile("pxor %xmm4, %xmm4"); | ||
|
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| for (; ip < ipend; ip += 2) { | ||
| asm volatile("movdqu %0, %%xmm5" :: "m"(*ip)); | ||
| asm volatile("movdqa %xmm5, %xmm6"); | ||
| asm volatile("punpckldq %xmm4, %xmm5"); | ||
| asm volatile("punpckhdq %xmm4, %xmm6"); | ||
| asm volatile("paddq %xmm5, %xmm0"); | ||
| asm volatile("paddq %xmm0, %xmm1"); | ||
| asm volatile("paddq %xmm1, %xmm2"); | ||
| asm volatile("paddq %xmm2, %xmm3"); | ||
| asm volatile("paddq %xmm6, %xmm0"); | ||
| asm volatile("paddq %xmm0, %xmm1"); | ||
| asm volatile("paddq %xmm1, %xmm2"); | ||
| asm volatile("paddq %xmm2, %xmm3"); | ||
| } | ||
| } | ||
|
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| static void | ||
| fletcher_4_sse2_byteswap(const void *buf, uint64_t size, zio_cksum_t *unused) | ||
| { | ||
| const uint32_t *ip = buf; | ||
| const uint32_t *ipend = (uint32_t *)((uint8_t *)ip + size); | ||
|
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| for (; ip < ipend; ip += 2) { | ||
| uint32_t scratch; | ||
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| asm volatile("bswapl %0" : "=r"(scratch) : "0"(*ip)); | ||
| asm volatile("movd %0, %%xmm5" :: "r"(scratch)); | ||
| asm volatile("bswapl %0" : "=r"(scratch) : "0"(*(ip + 1))); | ||
| asm volatile("movd %0, %%xmm6" :: "r"(scratch)); | ||
| asm volatile("punpcklqdq %xmm6, %xmm5"); | ||
| asm volatile("paddq %xmm5, %xmm0"); | ||
| asm volatile("paddq %xmm0, %xmm1"); | ||
| asm volatile("paddq %xmm1, %xmm2"); | ||
| asm volatile("paddq %xmm2, %xmm3"); | ||
| } | ||
| } | ||
|
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| static boolean_t fletcher_4_sse2_valid(void) | ||
| { | ||
| return (zfs_sse2_available()); | ||
| } | ||
|
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| const fletcher_4_ops_t fletcher_4_sse2_ops = { | ||
| .init = fletcher_4_sse2_init, | ||
| .fini = fletcher_4_sse2_fini, | ||
| .compute = fletcher_4_sse2, | ||
| .compute_byteswap = fletcher_4_sse2_byteswap, | ||
| .valid = fletcher_4_sse2_valid, | ||
| .name = "sse2" | ||
| }; | ||
|
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| #endif /* defined(HAVE_SSE2) */ | ||
|
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| #if defined(HAVE_SSE2) && defined(HAVE_SSSE3) | ||
| static void | ||
| fletcher_4_ssse3_byteswap(const void *buf, uint64_t size, zio_cksum_t *unused) | ||
| { | ||
| static const struct zfs_fletcher_sse_array mask = { | ||
| .v = { 0x0405060700010203, 0x0C0D0E0F08090A0B } | ||
| }; | ||
|
|
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| const uint64_t *ip = buf; | ||
| const uint64_t *ipend = (uint64_t *)((uint8_t *)ip + size); | ||
|
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| asm volatile("movdqa %0, %%xmm7"::"m" (mask)); | ||
| asm volatile("pxor %xmm4, %xmm4"); | ||
|
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| for (; ip < ipend; ip += 2) { | ||
| asm volatile("movdqu %0, %%xmm5"::"m" (*ip)); | ||
| asm volatile("pshufb %xmm7, %xmm5"); | ||
| asm volatile("movdqa %xmm5, %xmm6"); | ||
| asm volatile("punpckldq %xmm4, %xmm5"); | ||
| asm volatile("punpckhdq %xmm4, %xmm6"); | ||
| asm volatile("paddq %xmm5, %xmm0"); | ||
| asm volatile("paddq %xmm0, %xmm1"); | ||
| asm volatile("paddq %xmm1, %xmm2"); | ||
| asm volatile("paddq %xmm2, %xmm3"); | ||
| asm volatile("paddq %xmm6, %xmm0"); | ||
| asm volatile("paddq %xmm0, %xmm1"); | ||
| asm volatile("paddq %xmm1, %xmm2"); | ||
| asm volatile("paddq %xmm2, %xmm3"); | ||
| } | ||
| } | ||
|
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| static boolean_t fletcher_4_ssse3_valid(void) | ||
| { | ||
| return (zfs_sse2_available() && zfs_ssse3_available()); | ||
| } | ||
|
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| const fletcher_4_ops_t fletcher_4_ssse3_ops = { | ||
| .init = fletcher_4_sse2_init, | ||
| .fini = fletcher_4_sse2_fini, | ||
| .compute = fletcher_4_sse2, | ||
| .compute_byteswap = fletcher_4_ssse3_byteswap, | ||
| .valid = fletcher_4_ssse3_valid, | ||
| .name = "ssse3" | ||
| }; | ||
|
|
||
| #endif /* defined(HAVE_SSE2) && defined(HAVE_SSSE3) */ |