freebsd-nq/module/zcommon/zfs_fletcher_sse.c
Romain Dolbeau 7f3194932d Add superscalar fletcher4
This is the Fletcher4 algorithm implemented in pure C, but using
multiple counters using algorithms identical to those used for
SSE/NEON and AVX2.

This allows for faster execution on core with strong superscalar
capabilities but weak SIMD capabilities.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Romain Dolbeau <romain.dolbeau@atos.net>
Closes #5317
2016-11-04 10:53:03 -07:00

230 lines
6.9 KiB
C

/*
* Implement fast Fletcher4 with SSE2,SSSE3 instructions. (x86)
*
* Use the 128-bit SSE2/SSSE3 SIMD instructions and registers to compute
* Fletcher4 in two 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 <stachecki.tyler@gmail.com>
*
* 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)
#include <linux/simd_x86.h>
#include <sys/spa_checksum.h>
#include <sys/byteorder.h>
#include <zfs_fletcher.h>
#include <strings.h>
static void
fletcher_4_sse2_init(fletcher_4_ctx_t *ctx) {
bzero(ctx->sse, 4 * sizeof (zfs_fletcher_sse_t));
}
static void
fletcher_4_sse2_fini(fletcher_4_ctx_t *ctx, zio_cksum_t *zcp) {
uint64_t A, B, C, D;
/*
* 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 = ctx->sse[0].v[0] + ctx->sse[0].v[1];
B = 2 * ctx->sse[1].v[0] + 2 * ctx->sse[1].v[1] - ctx->sse[0].v[1];
C = 4 * ctx->sse[2].v[0] - ctx->sse[1].v[0] + 4 * ctx->sse[2].v[1] -
3 * ctx->sse[1].v[1];
D = 8 * ctx->sse[3].v[0] - 4 * ctx->sse[2].v[0] + 8 * ctx->sse[3].v[1] -
8 * ctx->sse[2].v[1] + ctx->sse[1].v[1];
ZIO_SET_CHECKSUM(zcp, A, B, C, D);
}
#define FLETCHER_4_SSE_RESTORE_CTX(ctx) \
{ \
asm volatile("movdqu %0, %%xmm0" :: "m" ((ctx)->sse[0])); \
asm volatile("movdqu %0, %%xmm1" :: "m" ((ctx)->sse[1])); \
asm volatile("movdqu %0, %%xmm2" :: "m" ((ctx)->sse[2])); \
asm volatile("movdqu %0, %%xmm3" :: "m" ((ctx)->sse[3])); \
}
#define FLETCHER_4_SSE_SAVE_CTX(ctx) \
{ \
asm volatile("movdqu %%xmm0, %0" : "=m" ((ctx)->sse[0])); \
asm volatile("movdqu %%xmm1, %0" : "=m" ((ctx)->sse[1])); \
asm volatile("movdqu %%xmm2, %0" : "=m" ((ctx)->sse[2])); \
asm volatile("movdqu %%xmm3, %0" : "=m" ((ctx)->sse[3])); \
}
static void
fletcher_4_sse2_native(fletcher_4_ctx_t *ctx, const void *buf, uint64_t size)
{
const uint64_t *ip = buf;
const uint64_t *ipend = (uint64_t *)((uint8_t *)ip + size);
kfpu_begin();
FLETCHER_4_SSE_RESTORE_CTX(ctx);
asm volatile("pxor %xmm4, %xmm4");
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");
}
FLETCHER_4_SSE_SAVE_CTX(ctx);
kfpu_end();
}
static void
fletcher_4_sse2_byteswap(fletcher_4_ctx_t *ctx, const void *buf, uint64_t size)
{
const uint32_t *ip = buf;
const uint32_t *ipend = (uint32_t *)((uint8_t *)ip + size);
kfpu_begin();
FLETCHER_4_SSE_RESTORE_CTX(ctx);
for (; ip < ipend; ip += 2) {
uint32_t scratch1 = BSWAP_32(ip[0]);
uint32_t scratch2 = BSWAP_32(ip[1]);
asm volatile("movd %0, %%xmm5" :: "r"(scratch1));
asm volatile("movd %0, %%xmm6" :: "r"(scratch2));
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");
}
FLETCHER_4_SSE_SAVE_CTX(ctx);
kfpu_end();
}
static boolean_t fletcher_4_sse2_valid(void)
{
return (zfs_sse2_available());
}
const fletcher_4_ops_t fletcher_4_sse2_ops = {
.init_native = fletcher_4_sse2_init,
.fini_native = fletcher_4_sse2_fini,
.compute_native = fletcher_4_sse2_native,
.init_byteswap = fletcher_4_sse2_init,
.fini_byteswap = fletcher_4_sse2_fini,
.compute_byteswap = fletcher_4_sse2_byteswap,
.valid = fletcher_4_sse2_valid,
.name = "sse2"
};
#endif /* defined(HAVE_SSE2) */
#if defined(HAVE_SSE2) && defined(HAVE_SSSE3)
static void
fletcher_4_ssse3_byteswap(fletcher_4_ctx_t *ctx, const void *buf, uint64_t size)
{
static const zfs_fletcher_sse_t mask = {
.v = { 0x0405060700010203, 0x0C0D0E0F08090A0B }
};
const uint64_t *ip = buf;
const uint64_t *ipend = (uint64_t *)((uint8_t *)ip + size);
kfpu_begin();
FLETCHER_4_SSE_RESTORE_CTX(ctx);
asm volatile("movdqu %0, %%xmm7"::"m" (mask));
asm volatile("pxor %xmm4, %xmm4");
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");
}
FLETCHER_4_SSE_SAVE_CTX(ctx);
kfpu_end();
}
static boolean_t fletcher_4_ssse3_valid(void)
{
return (zfs_sse2_available() && zfs_ssse3_available());
}
const fletcher_4_ops_t fletcher_4_ssse3_ops = {
.init_native = fletcher_4_sse2_init,
.fini_native = fletcher_4_sse2_fini,
.compute_native = fletcher_4_sse2_native,
.init_byteswap = fletcher_4_sse2_init,
.fini_byteswap = fletcher_4_sse2_fini,
.compute_byteswap = fletcher_4_ssse3_byteswap,
.valid = fletcher_4_ssse3_valid,
.name = "ssse3"
};
#endif /* defined(HAVE_SSE2) && defined(HAVE_SSSE3) */