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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#include "cache/lru_cache.h"
#include <string>
#include <vector>
#include "port/port.h"
#include "util/testharness.h"
namespace rocksdb {
class LRUCacheTest : public testing::Test {
public:
LRUCacheTest() {}
~LRUCacheTest() { DeleteCache(); }
void DeleteCache() {
if (cache_ != nullptr) {
cache_->~LRUCacheShard();
port::cacheline_aligned_free(cache_);
cache_ = nullptr;
}
}
void NewCache(size_t capacity, double high_pri_pool_ratio = 0.0) {
DeleteCache();
cache_ = reinterpret_cast<LRUCacheShard*>(
port::cacheline_aligned_alloc(sizeof(LRUCacheShard)));
new (cache_) LRUCacheShard(capacity, false /*strict_capcity_limit*/,
high_pri_pool_ratio);
}
void Insert(const std::string& key,
Cache::Priority priority = Cache::Priority::LOW) {
cache_->Insert(key, 0 /*hash*/, nullptr /*value*/, 1 /*charge*/,
nullptr /*deleter*/, nullptr /*handle*/, priority);
}
void Insert(char key, Cache::Priority priority = Cache::Priority::LOW) {
Insert(std::string(1, key), priority);
}
bool Lookup(const std::string& key) {
auto handle = cache_->Lookup(key, 0 /*hash*/);
if (handle) {
cache_->Release(handle);
return true;
}
return false;
}
bool Lookup(char key) { return Lookup(std::string(1, key)); }
void Erase(const std::string& key) { cache_->Erase(key, 0 /*hash*/); }
void ValidateLRUList(std::vector<std::string> keys,
size_t num_high_pri_pool_keys = 0) {
LRUHandle* lru;
LRUHandle* lru_low_pri;
cache_->TEST_GetLRUList(&lru, &lru_low_pri);
LRUHandle* iter = lru;
bool in_high_pri_pool = false;
size_t high_pri_pool_keys = 0;
if (iter == lru_low_pri) {
in_high_pri_pool = true;
}
for (const auto& key : keys) {
iter = iter->next;
ASSERT_NE(lru, iter);
ASSERT_EQ(key, iter->key().ToString());
ASSERT_EQ(in_high_pri_pool, iter->InHighPriPool());
if (in_high_pri_pool) {
high_pri_pool_keys++;
}
if (iter == lru_low_pri) {
ASSERT_FALSE(in_high_pri_pool);
in_high_pri_pool = true;
}
}
ASSERT_EQ(lru, iter->next);
ASSERT_TRUE(in_high_pri_pool);
ASSERT_EQ(num_high_pri_pool_keys, high_pri_pool_keys);
}
private:
LRUCacheShard* cache_ = nullptr;
};
TEST_F(LRUCacheTest, BasicLRU) {
NewCache(5);
for (char ch = 'a'; ch <= 'e'; ch++) {
Insert(ch);
}
ValidateLRUList({"a", "b", "c", "d", "e"});
for (char ch = 'x'; ch <= 'z'; ch++) {
Insert(ch);
}
ValidateLRUList({"d", "e", "x", "y", "z"});
ASSERT_FALSE(Lookup("b"));
ValidateLRUList({"d", "e", "x", "y", "z"});
ASSERT_TRUE(Lookup("e"));
ValidateLRUList({"d", "x", "y", "z", "e"});
ASSERT_TRUE(Lookup("z"));
ValidateLRUList({"d", "x", "y", "e", "z"});
Erase("x");
ValidateLRUList({"d", "y", "e", "z"});
ASSERT_TRUE(Lookup("d"));
ValidateLRUList({"y", "e", "z", "d"});
Insert("u");
ValidateLRUList({"y", "e", "z", "d", "u"});
Insert("v");
ValidateLRUList({"e", "z", "d", "u", "v"});
}
TEST_F(LRUCacheTest, MidpointInsertion) {
// Allocate 2 cache entries to high-pri pool.
NewCache(5, 0.45);
Insert("a", Cache::Priority::LOW);
Insert("b", Cache::Priority::LOW);
Insert("c", Cache::Priority::LOW);
Insert("x", Cache::Priority::HIGH);
Insert("y", Cache::Priority::HIGH);
ValidateLRUList({"a", "b", "c", "x", "y"}, 2);
// Low-pri entries inserted to the tail of low-pri list (the midpoint).
// After lookup, it will move to the tail of the full list.
Insert("d", Cache::Priority::LOW);
ValidateLRUList({"b", "c", "d", "x", "y"}, 2);
ASSERT_TRUE(Lookup("d"));
ValidateLRUList({"b", "c", "x", "y", "d"}, 2);
// High-pri entries will be inserted to the tail of full list.
Insert("z", Cache::Priority::HIGH);
ValidateLRUList({"c", "x", "y", "d", "z"}, 2);
}
TEST_F(LRUCacheTest, EntriesWithPriority) {
// Allocate 2 cache entries to high-pri pool.
NewCache(5, 0.45);
Insert("a", Cache::Priority::LOW);
Insert("b", Cache::Priority::LOW);
Insert("c", Cache::Priority::LOW);
ValidateLRUList({"a", "b", "c"}, 0);
// Low-pri entries can take high-pri pool capacity if available
Insert("u", Cache::Priority::LOW);
Insert("v", Cache::Priority::LOW);
ValidateLRUList({"a", "b", "c", "u", "v"}, 0);
Insert("X", Cache::Priority::HIGH);
Insert("Y", Cache::Priority::HIGH);
ValidateLRUList({"c", "u", "v", "X", "Y"}, 2);
// High-pri entries can overflow to low-pri pool.
Insert("Z", Cache::Priority::HIGH);
ValidateLRUList({"u", "v", "X", "Y", "Z"}, 2);
// Low-pri entries will be inserted to head of low-pri pool.
Insert("a", Cache::Priority::LOW);
ValidateLRUList({"v", "X", "a", "Y", "Z"}, 2);
// Low-pri entries will be inserted to head of high-pri pool after lookup.
ASSERT_TRUE(Lookup("v"));
ValidateLRUList({"X", "a", "Y", "Z", "v"}, 2);
// High-pri entries will be inserted to the head of the list after lookup.
ASSERT_TRUE(Lookup("X"));
ValidateLRUList({"a", "Y", "Z", "v", "X"}, 2);
ASSERT_TRUE(Lookup("Z"));
ValidateLRUList({"a", "Y", "v", "X", "Z"}, 2);
Erase("Y");
ValidateLRUList({"a", "v", "X", "Z"}, 2);
Erase("X");
ValidateLRUList({"a", "v", "Z"}, 1);
Insert("d", Cache::Priority::LOW);
Insert("e", Cache::Priority::LOW);
ValidateLRUList({"a", "v", "d", "e", "Z"}, 1);
Insert("f", Cache::Priority::LOW);
Insert("g", Cache::Priority::LOW);
ValidateLRUList({"d", "e", "f", "g", "Z"}, 1);
ASSERT_TRUE(Lookup("d"));
ValidateLRUList({"e", "f", "g", "Z", "d"}, 2);
}
} // namespace rocksdb
int main(int argc, char** argv) {
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}
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