1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
|
// Copyright 2022 The Abseil Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef ABSL_CRC_INTERNAL_NON_TEMPORAL_MEMCPY_H_
#define ABSL_CRC_INTERNAL_NON_TEMPORAL_MEMCPY_H_
#include <algorithm>
#include <cassert>
#include <cstring>
#include <iostream>
#include "absl/base/config.h"
#include "absl/base/optimization.h"
#ifdef __SSE__
// Only include if we're running on a CPU that supports SSE ISA, needed for
// sfence
#include <immintrin.h> // IWYU pragma: keep
#endif
#ifdef __SSE2__
// Only include if we're running on a CPU that supports SSE2 ISA, needed for
// movdqa, movdqu, movntdq
#include <emmintrin.h> // IWYU pragma: keep
#endif
#ifdef __aarch64__
// Only include if we're running on a CPU that supports ARM NEON ISA, needed for
// sfence, movdqa, movdqu, movntdq
#include "absl/crc/internal/non_temporal_arm_intrinsics.h"
#endif
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace crc_internal {
// This non-temporal memcpy does regular load and non-temporal store memory
// copy. It is compatible to both 16-byte aligned and unaligned addresses. If
// data at the destination is not immediately accessed, using non-temporal
// memcpy can save 1 DRAM load of the destination cacheline.
constexpr int kCacheLineSize = ABSL_CACHELINE_SIZE;
// If the objects overlap, the behavior is undefined.
// MSVC does not have proper header support for some of these intrinsics,
// so it should go to fallback
inline void *non_temporal_store_memcpy(void *__restrict dst,
const void *__restrict src, size_t len) {
#if (defined(__SSE3__) || defined(__aarch64__)) && !defined(_MSC_VER)
uint8_t *d = reinterpret_cast<uint8_t *>(dst);
const uint8_t *s = reinterpret_cast<const uint8_t *>(src);
// memcpy() the misaligned header. At the end of this if block, <d> is
// aligned to a 64-byte cacheline boundary or <len> == 0.
if (reinterpret_cast<uintptr_t>(d) & (kCacheLineSize - 1)) {
uintptr_t bytes_before_alignment_boundary =
kCacheLineSize -
(reinterpret_cast<uintptr_t>(d) & (kCacheLineSize - 1));
int header_len = (std::min)(bytes_before_alignment_boundary, len);
assert(bytes_before_alignment_boundary < kCacheLineSize);
memcpy(d, s, header_len);
d += header_len;
s += header_len;
len -= header_len;
}
if (len >= kCacheLineSize) {
_mm_sfence();
__m128i *dst_cacheline = reinterpret_cast<__m128i *>(d);
const __m128i *src_cacheline = reinterpret_cast<const __m128i *>(s);
constexpr int kOpsPerCacheLine = kCacheLineSize / sizeof(__m128i);
uint64_t loops = len / kCacheLineSize;
while (len >= kCacheLineSize) {
__m128i temp1, temp2, temp3, temp4;
temp1 = _mm_lddqu_si128(src_cacheline + 0);
temp2 = _mm_lddqu_si128(src_cacheline + 1);
temp3 = _mm_lddqu_si128(src_cacheline + 2);
temp4 = _mm_lddqu_si128(src_cacheline + 3);
_mm_stream_si128(dst_cacheline + 0, temp1);
_mm_stream_si128(dst_cacheline + 1, temp2);
_mm_stream_si128(dst_cacheline + 2, temp3);
_mm_stream_si128(dst_cacheline + 3, temp4);
src_cacheline += kOpsPerCacheLine;
dst_cacheline += kOpsPerCacheLine;
len -= kCacheLineSize;
}
d += loops * kCacheLineSize;
s += loops * kCacheLineSize;
_mm_sfence();
}
// memcpy the tail.
if (len) {
memcpy(d, s, len);
}
return dst;
#else
// Fallback to regular memcpy when SSE2/3 & aarch64 is not available.
return memcpy(dst, src, len);
#endif // __SSE3__ || __aarch64__
}
// MSVC does not have proper header support for some of these intrinsics,
// so it should go to fallback
inline void *non_temporal_store_memcpy_avx(void *__restrict dst,
const void *__restrict src,
size_t len) {
#if defined(__AVX__) && !defined(_MSC_VER)
uint8_t *d = reinterpret_cast<uint8_t *>(dst);
const uint8_t *s = reinterpret_cast<const uint8_t *>(src);
// memcpy() the misaligned header. At the end of this if block, <d> is
// aligned to a 64-byte cacheline boundary or <len> == 0.
if (reinterpret_cast<uintptr_t>(d) & (kCacheLineSize - 1)) {
uintptr_t bytes_before_alignment_boundary =
kCacheLineSize -
(reinterpret_cast<uintptr_t>(d) & (kCacheLineSize - 1));
int header_len = (std::min)(bytes_before_alignment_boundary, len);
assert(bytes_before_alignment_boundary < kCacheLineSize);
memcpy(d, s, header_len);
d += header_len;
s += header_len;
len -= header_len;
}
if (len >= kCacheLineSize) {
_mm_sfence();
__m256i *dst_cacheline = reinterpret_cast<__m256i *>(d);
const __m256i *src_cacheline = reinterpret_cast<const __m256i *>(s);
constexpr int kOpsPerCacheLine = kCacheLineSize / sizeof(__m256i);
int loops = len / kCacheLineSize;
while (len >= kCacheLineSize) {
__m256i temp1, temp2;
temp1 = _mm256_lddqu_si256(src_cacheline + 0);
temp2 = _mm256_lddqu_si256(src_cacheline + 1);
_mm256_stream_si256(dst_cacheline + 0, temp1);
_mm256_stream_si256(dst_cacheline + 1, temp2);
src_cacheline += kOpsPerCacheLine;
dst_cacheline += kOpsPerCacheLine;
len -= kCacheLineSize;
}
d += loops * kCacheLineSize;
s += loops * kCacheLineSize;
_mm_sfence();
}
// memcpy the tail.
if (len) {
memcpy(d, s, len);
}
return dst;
#else
// Fallback to regular memcpy when AVX is not available.
return memcpy(dst, src, len);
#endif // __AVX__
}
} // namespace crc_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_CRC_INTERNAL_NON_TEMPORAL_MEMCPY_H_
|
