zfs-builds-mm/zfs-0.8.2/module/zcommon/zfs_fletcher_superscalar.c

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2019-10-24 23:13:56 +02:00
/*
* Implement fast Fletcher4 using superscalar pipelines.
*
* Use regular C code 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 Romain Dolbeau.
*
* Authors:
* Romain Dolbeau <romain.dolbeau@atos.net>
*
* 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.
*/
#include <sys/byteorder.h>
#include <sys/spa_checksum.h>
#include <sys/strings.h>
#include <zfs_fletcher.h>
static void
fletcher_4_superscalar_init(fletcher_4_ctx_t *ctx)
{
bzero(ctx->superscalar, 4 * sizeof (zfs_fletcher_superscalar_t));
}
static void
fletcher_4_superscalar_fini(fletcher_4_ctx_t *ctx, zio_cksum_t *zcp)
{
uint64_t A, B, C, D;
A = ctx->superscalar[0].v[0] + ctx->superscalar[0].v[1];
B = 2 * ctx->superscalar[1].v[0] + 2 * ctx->superscalar[1].v[1] -
ctx->superscalar[0].v[1];
C = 4 * ctx->superscalar[2].v[0] - ctx->superscalar[1].v[0] +
4 * ctx->superscalar[2].v[1] - 3 * ctx->superscalar[1].v[1];
D = 8 * ctx->superscalar[3].v[0] - 4 * ctx->superscalar[2].v[0] +
8 * ctx->superscalar[3].v[1] - 8 * ctx->superscalar[2].v[1] +
ctx->superscalar[1].v[1];
ZIO_SET_CHECKSUM(zcp, A, B, C, D);
}
static void
fletcher_4_superscalar_native(fletcher_4_ctx_t *ctx,
const void *buf, uint64_t size)
{
const uint32_t *ip = buf;
const uint32_t *ipend = ip + (size / sizeof (uint32_t));
uint64_t a, b, c, d;
uint64_t a2, b2, c2, d2;
a = ctx->superscalar[0].v[0];
b = ctx->superscalar[1].v[0];
c = ctx->superscalar[2].v[0];
d = ctx->superscalar[3].v[0];
a2 = ctx->superscalar[0].v[1];
b2 = ctx->superscalar[1].v[1];
c2 = ctx->superscalar[2].v[1];
d2 = ctx->superscalar[3].v[1];
for (; ip < ipend; ip += 2) {
a += ip[0];
a2 += ip[1];
b += a;
b2 += a2;
c += b;
c2 += b2;
d += c;
d2 += c2;
}
ctx->superscalar[0].v[0] = a;
ctx->superscalar[1].v[0] = b;
ctx->superscalar[2].v[0] = c;
ctx->superscalar[3].v[0] = d;
ctx->superscalar[0].v[1] = a2;
ctx->superscalar[1].v[1] = b2;
ctx->superscalar[2].v[1] = c2;
ctx->superscalar[3].v[1] = d2;
}
static void
fletcher_4_superscalar_byteswap(fletcher_4_ctx_t *ctx,
const void *buf, uint64_t size)
{
const uint32_t *ip = buf;
const uint32_t *ipend = ip + (size / sizeof (uint32_t));
uint64_t a, b, c, d;
uint64_t a2, b2, c2, d2;
a = ctx->superscalar[0].v[0];
b = ctx->superscalar[1].v[0];
c = ctx->superscalar[2].v[0];
d = ctx->superscalar[3].v[0];
a2 = ctx->superscalar[0].v[1];
b2 = ctx->superscalar[1].v[1];
c2 = ctx->superscalar[2].v[1];
d2 = ctx->superscalar[3].v[1];
for (; ip < ipend; ip += 2) {
a += BSWAP_32(ip[0]);
a2 += BSWAP_32(ip[1]);
b += a;
b2 += a2;
c += b;
c2 += b2;
d += c;
d2 += c2;
}
ctx->superscalar[0].v[0] = a;
ctx->superscalar[1].v[0] = b;
ctx->superscalar[2].v[0] = c;
ctx->superscalar[3].v[0] = d;
ctx->superscalar[0].v[1] = a2;
ctx->superscalar[1].v[1] = b2;
ctx->superscalar[2].v[1] = c2;
ctx->superscalar[3].v[1] = d2;
}
static boolean_t fletcher_4_superscalar_valid(void)
{
return (B_TRUE);
}
const fletcher_4_ops_t fletcher_4_superscalar_ops = {
.init_native = fletcher_4_superscalar_init,
.compute_native = fletcher_4_superscalar_native,
.fini_native = fletcher_4_superscalar_fini,
.init_byteswap = fletcher_4_superscalar_init,
.compute_byteswap = fletcher_4_superscalar_byteswap,
.fini_byteswap = fletcher_4_superscalar_fini,
.valid = fletcher_4_superscalar_valid,
.name = "superscalar"
};