2 * Copyright 2017 Facebook, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 #include <folly/CachelinePadded.h>
19 #include <type_traits>
21 #include <folly/lang/Align.h>
22 #include <folly/portability/GTest.h>
24 using folly::CachelinePadded;
27 std::is_standard_layout<CachelinePadded<int>>::value,
28 "CachelinePadded<T> must be standard-layout if T is.");
30 static constexpr int kCachelineSize =
31 folly::hardware_destructive_interference_size;
33 template <size_t dataSize, size_t alignment = alignof(void*)>
34 struct alignas(alignment) SizedData {
37 for (auto& datum : data) {
42 void doModifications() {
44 for (auto& datum : data) {
45 EXPECT_EQ(static_cast<unsigned char>(i++), datum);
52 for (auto& datum : data) {
53 EXPECT_EQ(static_cast<unsigned char>(i++), datum);
57 unsigned char data[dataSize];
60 template <typename T, size_t N = 1>
61 using SizedDataMimic = SizedData<N * sizeof(T), alignof(T)>;
64 struct CachelinePaddedTests : ::testing::Test {};
66 using CachelinePaddedTypes = ::testing::Types<
67 SizedData<kCachelineSize>,
68 SizedData<2 * kCachelineSize>,
69 SizedData<kCachelineSize / 2>,
70 SizedData<kCachelineSize + kCachelineSize / 2>,
71 // Mimic single basic types:
72 SizedDataMimic<folly::max_align_t>,
73 SizedDataMimic<void*>,
74 SizedDataMimic<long double>,
75 SizedDataMimic<double>,
76 SizedDataMimic<float>,
77 SizedDataMimic<long long>,
80 SizedDataMimic<short>,
82 // Mimic small arrays of basic types:
83 SizedDataMimic<folly::max_align_t, 3>,
84 SizedDataMimic<void*, 3>,
85 SizedDataMimic<long double, 3>,
86 SizedDataMimic<double, 3>,
87 SizedDataMimic<float, 3>,
88 SizedDataMimic<long long, 3>,
89 SizedDataMimic<long, 3>,
90 SizedDataMimic<int, 3>,
91 SizedDataMimic<short, 3>,
92 SizedDataMimic<char, 3>,
93 // Mimic large arrays of basic types:
94 SizedDataMimic<folly::max_align_t, kCachelineSize + 3>,
95 SizedDataMimic<void*, kCachelineSize + 3>,
96 SizedDataMimic<long double, kCachelineSize + 3>,
97 SizedDataMimic<double, kCachelineSize + 3>,
98 SizedDataMimic<float, kCachelineSize + 3>,
99 SizedDataMimic<long long, kCachelineSize + 3>,
100 SizedDataMimic<long, kCachelineSize + 3>,
101 SizedDataMimic<int, kCachelineSize + 3>,
102 SizedDataMimic<short, kCachelineSize + 3>,
103 SizedDataMimic<char, kCachelineSize + 3>>;
104 TYPED_TEST_CASE(CachelinePaddedTests, CachelinePaddedTypes);
106 TYPED_TEST(CachelinePaddedTests, alignment) {
107 EXPECT_EQ(alignof(TypeParam), alignof(CachelinePadded<TypeParam>));
110 TYPED_TEST(CachelinePaddedTests, integrity) {
111 CachelinePadded<TypeParam> item;
112 item.get()->doModifications();
115 TYPED_TEST(CachelinePaddedTests, size) {
117 sizeof(TypeParam) + 2 * kCachelineSize,
118 sizeof(CachelinePadded<TypeParam>));
119 size_t const rawSize = sizeof(TypeParam);
120 size_t const rawAlign = alignof(TypeParam);
121 size_t const expectedPadding = kCachelineSize - (rawAlign % kCachelineSize);
122 size_t const expectedPaddedSize = rawSize + 2 * expectedPadding;
123 EXPECT_EQ(expectedPaddedSize, sizeof(CachelinePadded<TypeParam>));
126 TEST(CachelinePadded, PtrOperator) {
127 CachelinePadded<int> padded;
128 EXPECT_TRUE(padded.get() == padded.operator->());
129 EXPECT_TRUE(&*padded == padded.get());
130 const CachelinePadded<int> constPadded;
131 EXPECT_TRUE(constPadded.get() == constPadded.operator->());
132 EXPECT_TRUE(constPadded.get() == &*constPadded.get());
135 TEST(CachelinePadded, PropagatesConstness) {
136 struct OverloadedOnConst {
137 void assign(int* dst) {
140 void assign(int* dst) const {
145 CachelinePadded<OverloadedOnConst> padded;
151 const CachelinePadded<OverloadedOnConst> constPadded;
152 constPadded->assign(&i);
153 EXPECT_EQ(271828, i);
156 TEST(CachelinePadded, ConstructsAndDestructs) {
157 enum LifetimeStatus {
162 struct WriteOnLifetimeOp {
163 explicit WriteOnLifetimeOp(LifetimeStatus* dst) : dst_(dst) {
166 ~WriteOnLifetimeOp() {
169 LifetimeStatus* dst_;
171 LifetimeStatus status = kNone;
172 CachelinePadded<WriteOnLifetimeOp>* ptr =
173 new CachelinePadded<WriteOnLifetimeOp>(&status);
174 EXPECT_EQ(kConstructed, status);
176 EXPECT_EQ(kDestroyed, status);
179 TEST(CachelinePadded, ConstructsAndDestructsArrays) {
180 static thread_local int numConstructions;
181 static thread_local int numDestructions;
182 numConstructions = 0;
184 struct LifetimeCountingClass {
185 LifetimeCountingClass() {
188 ~LifetimeCountingClass() {
192 const static int kNumItems = 123;
193 CachelinePadded<LifetimeCountingClass>* ptr =
194 new CachelinePadded<LifetimeCountingClass>[kNumItems];
195 EXPECT_EQ(kNumItems, numConstructions);
197 EXPECT_EQ(kNumItems, numDestructions);
200 TEST(CachelinePadded, ForwardsCorrectly) {
201 struct RvalueOverloadedConstructor {
202 RvalueOverloadedConstructor(int* dst, int& /* ignored */) {
205 RvalueOverloadedConstructor(int* dst, int&& /* ignored */) {
209 int shouldBeZero = 12345;
210 int shouldBeOne = 67890;
213 CachelinePadded<RvalueOverloadedConstructor> padded1(
214 &shouldBeZero, ignored);
215 CachelinePadded<RvalueOverloadedConstructor> padded2(
216 &shouldBeOne, static_cast<int&&>(ignored));
218 EXPECT_EQ(0, shouldBeZero);
219 EXPECT_EQ(1, shouldBeOne);