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// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/sampling_heap_profiler/lock_free_address_hash_set.h"
#include <stdlib.h>
#include <atomic>
#include <cinttypes>
#include <memory>
#include "base/allocator/partition_allocator/src/partition_alloc/shim/allocator_shim.h"
#include "base/debug/alias.h"
#include "base/memory/raw_ptr.h"
#include "base/threading/simple_thread.h"
#include "testing/gtest/include/gtest/gtest.h"
namespace base {
class LockFreeAddressHashSetTest : public ::testing::Test {
public:
static bool IsSubset(const LockFreeAddressHashSet& superset,
const LockFreeAddressHashSet& subset) {
for (const std::atomic<LockFreeAddressHashSet::Node*>& bucket :
subset.buckets_) {
for (LockFreeAddressHashSet::Node* node =
bucket.load(std::memory_order_acquire);
node; node = node->next) {
void* key = node->key.load(std::memory_order_relaxed);
if (key && !superset.Contains(key))
return false;
}
}
return true;
}
static bool Equals(const LockFreeAddressHashSet& set1,
const LockFreeAddressHashSet& set2) {
return IsSubset(set1, set2) && IsSubset(set2, set1);
}
static size_t BucketSize(const LockFreeAddressHashSet& set, size_t bucket) {
size_t count = 0;
LockFreeAddressHashSet::Node* node =
set.buckets_[bucket].load(std::memory_order_acquire);
for (; node; node = node->next)
++count;
return count;
}
};
namespace {
TEST_F(LockFreeAddressHashSetTest, EmptySet) {
LockFreeAddressHashSet set(8);
EXPECT_EQ(size_t(0), set.size());
EXPECT_EQ(size_t(8), set.buckets_count());
EXPECT_EQ(0., set.load_factor());
EXPECT_FALSE(set.Contains(&set));
}
TEST_F(LockFreeAddressHashSetTest, BasicOperations) {
LockFreeAddressHashSet set(8);
for (size_t i = 1; i <= 100; ++i) {
void* ptr = reinterpret_cast<void*>(i);
set.Insert(ptr);
EXPECT_EQ(i, set.size());
EXPECT_TRUE(set.Contains(ptr));
}
size_t size = 100;
EXPECT_EQ(size, set.size());
EXPECT_EQ(size_t(8), set.buckets_count());
EXPECT_EQ(size / 8., set.load_factor());
for (size_t i = 99; i >= 3; i -= 3) {
void* ptr = reinterpret_cast<void*>(i);
set.Remove(ptr);
EXPECT_EQ(--size, set.size());
EXPECT_FALSE(set.Contains(ptr));
}
// Removed every 3rd value (33 total) from the set, 67 have left.
EXPECT_EQ(size_t(67), set.size());
for (size_t i = 1; i <= 100; ++i) {
void* ptr = reinterpret_cast<void*>(i);
EXPECT_EQ(i % 3 != 0, set.Contains(ptr));
}
}
TEST_F(LockFreeAddressHashSetTest, Copy) {
LockFreeAddressHashSet set(16);
for (size_t i = 1000; i <= 16000; i += 1000) {
void* ptr = reinterpret_cast<void*>(i);
set.Insert(ptr);
}
LockFreeAddressHashSet set2(4);
LockFreeAddressHashSet set3(64);
set2.Copy(set);
set3.Copy(set);
EXPECT_TRUE(Equals(set, set2));
EXPECT_TRUE(Equals(set, set3));
EXPECT_TRUE(Equals(set2, set3));
set.Insert(reinterpret_cast<void*>(42));
EXPECT_FALSE(Equals(set, set2));
EXPECT_FALSE(Equals(set, set3));
EXPECT_TRUE(Equals(set2, set3));
EXPECT_TRUE(IsSubset(set, set2));
EXPECT_FALSE(IsSubset(set2, set));
}
class WriterThread : public SimpleThread {
public:
WriterThread(LockFreeAddressHashSet* set, std::atomic_bool* cancel)
: SimpleThread("ReaderThread"), set_(set), cancel_(cancel) {}
void Run() override {
for (size_t value = 42; !cancel_->load(std::memory_order_acquire);
++value) {
void* ptr = reinterpret_cast<void*>(value);
set_->Insert(ptr);
EXPECT_TRUE(set_->Contains(ptr));
set_->Remove(ptr);
EXPECT_FALSE(set_->Contains(ptr));
}
// Leave a key for reader to test.
set_->Insert(reinterpret_cast<void*>(0x1337));
}
private:
raw_ptr<LockFreeAddressHashSet> set_;
raw_ptr<std::atomic_bool> cancel_;
};
TEST_F(LockFreeAddressHashSetTest, ConcurrentAccess) {
// The purpose of this test is to make sure adding/removing keys concurrently
// does not disrupt the state of other keys.
LockFreeAddressHashSet set(16);
for (size_t i = 1; i <= 20; ++i)
set.Insert(reinterpret_cast<void*>(i));
// Remove some items to test empty nodes.
for (size_t i = 16; i <= 20; ++i)
set.Remove(reinterpret_cast<void*>(i));
std::atomic_bool cancel(false);
auto thread = std::make_unique<WriterThread>(&set, &cancel);
thread->Start();
for (size_t k = 0; k < 100000; ++k) {
for (size_t i = 1; i <= 30; ++i) {
EXPECT_EQ(i < 16, set.Contains(reinterpret_cast<void*>(i)));
}
}
cancel.store(true, std::memory_order_release);
thread->Join();
EXPECT_TRUE(set.Contains(reinterpret_cast<void*>(0x1337)));
EXPECT_FALSE(set.Contains(reinterpret_cast<void*>(0xbadf00d)));
}
TEST_F(LockFreeAddressHashSetTest, BucketsUsage) {
// Test the uniformity of buckets usage.
size_t count = 10000;
LockFreeAddressHashSet set(16);
for (size_t i = 0; i < count; ++i)
set.Insert(reinterpret_cast<void*>(0x10000 + 0x10 * i));
size_t average_per_bucket = count / set.buckets_count();
for (size_t i = 0; i < set.buckets_count(); ++i) {
size_t usage = BucketSize(set, i);
EXPECT_LT(average_per_bucket * 95 / 100, usage);
EXPECT_GT(average_per_bucket * 105 / 100, usage);
}
}
} // namespace
} // namespace base
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