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/portability/GTest.h>
23 using folly::CachelinePadded;
26 std::is_standard_layout<CachelinePadded<int>>::value,
27 "CachelinePadded<T> must be standard-layout if T is.");
29 static constexpr int kCachelineSize = folly::CacheLocality::kFalseSharingRange;
31 template <size_t dataSize, size_t alignment = alignof(void*)>
32 struct alignas(alignment) SizedData {
35 for (auto& datum : data) {
40 void doModifications() {
42 for (auto& datum : data) {
43 EXPECT_EQ(static_cast<unsigned char>(i++), datum);
50 for (auto& datum : data) {
51 EXPECT_EQ(static_cast<unsigned char>(i++), datum);
55 unsigned char data[dataSize];
58 template <typename T, size_t N = 1>
59 using SizedDataMimic = SizedData<N * sizeof(T), alignof(T)>;
62 struct CachelinePaddedTests : ::testing::Test {};
64 using CachelinePaddedTypes = ::testing::Types<
65 SizedData<kCachelineSize>,
66 SizedData<2 * kCachelineSize>,
67 SizedData<kCachelineSize / 2>,
68 SizedData<kCachelineSize + kCachelineSize / 2>,
69 // Mimic single basic types:
70 SizedDataMimic<folly::max_align_t>,
71 SizedDataMimic<void*>,
72 SizedDataMimic<long double>,
73 SizedDataMimic<double>,
74 SizedDataMimic<float>,
75 SizedDataMimic<long long>,
78 SizedDataMimic<short>,
80 // Mimic small arrays of basic types:
81 SizedDataMimic<folly::max_align_t, 3>,
82 SizedDataMimic<void*, 3>,
83 SizedDataMimic<long double, 3>,
84 SizedDataMimic<double, 3>,
85 SizedDataMimic<float, 3>,
86 SizedDataMimic<long long, 3>,
87 SizedDataMimic<long, 3>,
88 SizedDataMimic<int, 3>,
89 SizedDataMimic<short, 3>,
90 SizedDataMimic<char, 3>,
91 // Mimic large arrays of basic types:
92 SizedDataMimic<folly::max_align_t, kCachelineSize + 3>,
93 SizedDataMimic<void*, kCachelineSize + 3>,
94 SizedDataMimic<long double, kCachelineSize + 3>,
95 SizedDataMimic<double, kCachelineSize + 3>,
96 SizedDataMimic<float, kCachelineSize + 3>,
97 SizedDataMimic<long long, kCachelineSize + 3>,
98 SizedDataMimic<long, kCachelineSize + 3>,
99 SizedDataMimic<int, kCachelineSize + 3>,
100 SizedDataMimic<short, kCachelineSize + 3>,
101 SizedDataMimic<char, kCachelineSize + 3>>;
102 TYPED_TEST_CASE(CachelinePaddedTests, CachelinePaddedTypes);
104 TYPED_TEST(CachelinePaddedTests, alignment) {
105 EXPECT_EQ(alignof(TypeParam), alignof(CachelinePadded<TypeParam>));
108 TYPED_TEST(CachelinePaddedTests, integrity) {
109 CachelinePadded<TypeParam> item;
110 item.get()->doModifications();
113 TYPED_TEST(CachelinePaddedTests, size) {
115 sizeof(TypeParam) + 2 * kCachelineSize,
116 sizeof(CachelinePadded<TypeParam>));
117 size_t const rawSize = sizeof(TypeParam);
118 size_t const rawAlign = alignof(TypeParam);
119 size_t const expectedPadding = kCachelineSize - (rawAlign % kCachelineSize);
120 size_t const expectedPaddedSize = rawSize + 2 * expectedPadding;
121 EXPECT_EQ(expectedPaddedSize, sizeof(CachelinePadded<TypeParam>));
124 TEST(CachelinePadded, PtrOperator) {
125 CachelinePadded<int> padded;
126 EXPECT_TRUE(padded.get() == padded.operator->());
127 EXPECT_TRUE(&*padded == padded.get());
128 const CachelinePadded<int> constPadded;
129 EXPECT_TRUE(constPadded.get() == constPadded.operator->());
130 EXPECT_TRUE(constPadded.get() == &*constPadded.get());
133 TEST(CachelinePadded, PropagatesConstness) {
134 struct OverloadedOnConst {
135 void assign(int* dst) {
138 void assign(int* dst) const {
143 CachelinePadded<OverloadedOnConst> padded;
149 const CachelinePadded<OverloadedOnConst> constPadded;
150 constPadded->assign(&i);
151 EXPECT_EQ(271828, i);
154 TEST(CachelinePadded, ConstructsAndDestructs) {
155 enum LifetimeStatus {
160 struct WriteOnLifetimeOp {
161 explicit WriteOnLifetimeOp(LifetimeStatus* dst) : dst_(dst) {
164 ~WriteOnLifetimeOp() {
167 LifetimeStatus* dst_;
169 LifetimeStatus status = kNone;
170 CachelinePadded<WriteOnLifetimeOp>* ptr =
171 new CachelinePadded<WriteOnLifetimeOp>(&status);
172 EXPECT_EQ(kConstructed, status);
174 EXPECT_EQ(kDestroyed, status);
177 TEST(CachelinePadded, ConstructsAndDestructsArrays) {
178 static thread_local int numConstructions;
179 static thread_local int numDestructions;
180 numConstructions = 0;
182 struct LifetimeCountingClass {
183 LifetimeCountingClass() {
186 ~LifetimeCountingClass() {
190 const static int kNumItems = 123;
191 CachelinePadded<LifetimeCountingClass>* ptr =
192 new CachelinePadded<LifetimeCountingClass>[kNumItems];
193 EXPECT_EQ(kNumItems, numConstructions);
195 EXPECT_EQ(kNumItems, numDestructions);
198 TEST(CachelinePadded, ForwardsCorrectly) {
199 struct RvalueOverloadedConstructor {
200 RvalueOverloadedConstructor(int* dst, int& /* ignored */) {
203 RvalueOverloadedConstructor(int* dst, int&& /* ignored */) {
207 int shouldBeZero = 12345;
208 int shouldBeOne = 67890;
211 CachelinePadded<RvalueOverloadedConstructor> padded1(
212 &shouldBeZero, ignored);
213 CachelinePadded<RvalueOverloadedConstructor> padded2(
214 &shouldBeOne, static_cast<int&&>(ignored));
216 EXPECT_EQ(0, shouldBeZero);
217 EXPECT_EQ(1, shouldBeOne);