1a59b6e2a9
Summary: This PR adds a ghost cache for admission control. Specifically, it admits an entry on its second access. It also adds a hybrid row-block cache that caches the referenced key-value pairs of a Get/MultiGet request instead of its blocks. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5534 Test Plan: make clean && COMPILE_WITH_ASAN=1 make check -j32 Differential Revision: D16101124 Pulled By: HaoyuHuang fbshipit-source-id: b99edda6418a888e94eb40f71ece45d375e234b1
338 lines
14 KiB
C++
338 lines
14 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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#include "utilities/simulator_cache/cache_simulator.h"
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#include <cstdlib>
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#include "rocksdb/env.h"
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#include "test_util/testharness.h"
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#include "test_util/testutil.h"
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namespace rocksdb {
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namespace {
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const std::string kBlockKeyPrefix = "test-block-";
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const std::string kRefKeyPrefix = "test-get-";
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const uint64_t kGetId = 1;
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const uint64_t kGetBlockId = 100;
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const uint64_t kCompactionBlockId = 1000;
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const uint64_t kCacheSize = 1024 * 1024 * 1024;
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const uint64_t kGhostCacheSize = 1024 * 1024;
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} // namespace
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class CacheSimulatorTest : public testing::Test {
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public:
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const size_t kNumBlocks = 5;
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const size_t kValueSize = 1000;
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CacheSimulatorTest() { env_ = rocksdb::Env::Default(); }
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BlockCacheTraceRecord GenerateGetRecord(uint64_t getid) {
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BlockCacheTraceRecord record;
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record.block_type = TraceType::kBlockTraceDataBlock;
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record.block_size = 4096;
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record.block_key = kBlockKeyPrefix + std::to_string(kGetBlockId);
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record.access_timestamp = env_->NowMicros();
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record.cf_id = 0;
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record.cf_name = "test";
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record.caller = TableReaderCaller::kUserGet;
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record.level = 6;
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record.sst_fd_number = kGetBlockId;
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record.get_id = getid;
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record.is_cache_hit = Boolean::kFalse;
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record.no_insert = Boolean::kFalse;
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record.referenced_key =
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kRefKeyPrefix + std::to_string(kGetId) + std::string(8, 'c');
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record.referenced_key_exist_in_block = Boolean::kTrue;
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record.referenced_data_size = 100;
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record.num_keys_in_block = 300;
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return record;
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}
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BlockCacheTraceRecord GenerateCompactionRecord() {
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BlockCacheTraceRecord record;
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record.block_type = TraceType::kBlockTraceDataBlock;
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record.block_size = 4096;
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record.block_key = kBlockKeyPrefix + std::to_string(kCompactionBlockId);
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record.access_timestamp = env_->NowMicros();
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record.cf_id = 0;
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record.cf_name = "test";
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record.caller = TableReaderCaller::kCompaction;
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record.level = 6;
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record.sst_fd_number = kCompactionBlockId;
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record.is_cache_hit = Boolean::kFalse;
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record.no_insert = Boolean::kTrue;
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return record;
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}
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Env* env_;
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};
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TEST_F(CacheSimulatorTest, GhostCache) {
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const std::string key1 = "test1";
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const std::string key2 = "test2";
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std::unique_ptr<GhostCache> ghost_cache(new GhostCache(
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NewLRUCache(/*capacity=*/kGhostCacheSize, /*num_shard_bits=*/1,
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/*strict_capacity_limit=*/false,
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/*high_pri_pool_ratio=*/0)));
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EXPECT_FALSE(ghost_cache->Admit(key1));
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EXPECT_TRUE(ghost_cache->Admit(key1));
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EXPECT_TRUE(ghost_cache->Admit(key1));
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EXPECT_FALSE(ghost_cache->Admit(key2));
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EXPECT_TRUE(ghost_cache->Admit(key2));
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}
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TEST_F(CacheSimulatorTest, CacheSimulator) {
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const BlockCacheTraceRecord& access = GenerateGetRecord(kGetId);
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const BlockCacheTraceRecord& compaction_access = GenerateCompactionRecord();
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std::shared_ptr<Cache> sim_cache =
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NewLRUCache(/*capacity=*/kCacheSize, /*num_shard_bits=*/1,
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/*strict_capacity_limit=*/false,
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/*high_pri_pool_ratio=*/0);
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std::unique_ptr<CacheSimulator> cache_simulator(
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new CacheSimulator(nullptr, sim_cache));
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cache_simulator->Access(access);
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cache_simulator->Access(access);
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ASSERT_EQ(2, cache_simulator->total_accesses());
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ASSERT_EQ(50, cache_simulator->miss_ratio());
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ASSERT_EQ(2, cache_simulator->user_accesses());
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ASSERT_EQ(50, cache_simulator->user_miss_ratio());
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cache_simulator->Access(compaction_access);
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cache_simulator->Access(compaction_access);
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ASSERT_EQ(4, cache_simulator->total_accesses());
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ASSERT_EQ(75, cache_simulator->miss_ratio());
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ASSERT_EQ(2, cache_simulator->user_accesses());
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ASSERT_EQ(50, cache_simulator->user_miss_ratio());
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cache_simulator->reset_counter();
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ASSERT_EQ(0, cache_simulator->total_accesses());
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ASSERT_EQ(-1, cache_simulator->miss_ratio());
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auto handle = sim_cache->Lookup(access.block_key);
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ASSERT_NE(nullptr, handle);
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sim_cache->Release(handle);
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handle = sim_cache->Lookup(compaction_access.block_key);
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ASSERT_EQ(nullptr, handle);
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}
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TEST_F(CacheSimulatorTest, GhostCacheSimulator) {
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const BlockCacheTraceRecord& access = GenerateGetRecord(kGetId);
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std::unique_ptr<GhostCache> ghost_cache(new GhostCache(
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NewLRUCache(/*capacity=*/kGhostCacheSize, /*num_shard_bits=*/1,
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/*strict_capacity_limit=*/false,
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/*high_pri_pool_ratio=*/0)));
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std::unique_ptr<CacheSimulator> cache_simulator(new CacheSimulator(
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std::move(ghost_cache),
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NewLRUCache(/*capacity=*/kCacheSize, /*num_shard_bits=*/1,
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/*strict_capacity_limit=*/false,
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/*high_pri_pool_ratio=*/0)));
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cache_simulator->Access(access);
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cache_simulator->Access(access);
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ASSERT_EQ(2, cache_simulator->total_accesses());
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// Both of them will be miss since we have a ghost cache.
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ASSERT_EQ(100, cache_simulator->miss_ratio());
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}
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TEST_F(CacheSimulatorTest, PrioritizedCacheSimulator) {
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const BlockCacheTraceRecord& access = GenerateGetRecord(kGetId);
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std::shared_ptr<Cache> sim_cache =
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NewLRUCache(/*capacity=*/kCacheSize, /*num_shard_bits=*/1,
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/*strict_capacity_limit=*/false,
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/*high_pri_pool_ratio=*/0);
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std::unique_ptr<PrioritizedCacheSimulator> cache_simulator(
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new PrioritizedCacheSimulator(nullptr, sim_cache));
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cache_simulator->Access(access);
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cache_simulator->Access(access);
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ASSERT_EQ(2, cache_simulator->total_accesses());
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ASSERT_EQ(50, cache_simulator->miss_ratio());
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auto handle = sim_cache->Lookup(access.block_key);
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ASSERT_NE(nullptr, handle);
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sim_cache->Release(handle);
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}
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TEST_F(CacheSimulatorTest, GhostPrioritizedCacheSimulator) {
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const BlockCacheTraceRecord& access = GenerateGetRecord(kGetId);
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std::unique_ptr<GhostCache> ghost_cache(new GhostCache(
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NewLRUCache(/*capacity=*/kGhostCacheSize, /*num_shard_bits=*/1,
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/*strict_capacity_limit=*/false,
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/*high_pri_pool_ratio=*/0)));
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std::unique_ptr<PrioritizedCacheSimulator> cache_simulator(
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new PrioritizedCacheSimulator(
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std::move(ghost_cache),
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NewLRUCache(/*capacity=*/kCacheSize, /*num_shard_bits=*/1,
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/*strict_capacity_limit=*/false,
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/*high_pri_pool_ratio=*/0)));
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cache_simulator->Access(access);
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cache_simulator->Access(access);
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ASSERT_EQ(2, cache_simulator->total_accesses());
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// Both of them will be miss since we have a ghost cache.
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ASSERT_EQ(100, cache_simulator->miss_ratio());
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}
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TEST_F(CacheSimulatorTest, HybridRowBlockCacheSimulator) {
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uint64_t block_id = 100;
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BlockCacheTraceRecord first_get = GenerateGetRecord(kGetId);
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BlockCacheTraceRecord second_get = GenerateGetRecord(kGetId + 1);
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second_get.referenced_data_size = 0;
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second_get.referenced_key_exist_in_block = Boolean::kFalse;
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second_get.referenced_key = kRefKeyPrefix + std::to_string(kGetId);
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BlockCacheTraceRecord third_get = GenerateGetRecord(kGetId + 2);
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third_get.referenced_data_size = 0;
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third_get.referenced_key_exist_in_block = Boolean::kFalse;
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third_get.referenced_key = kRefKeyPrefix + "third_get";
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// We didn't find the referenced key in the third get.
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third_get.referenced_key_exist_in_block = Boolean::kFalse;
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third_get.referenced_data_size = 0;
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std::shared_ptr<Cache> sim_cache =
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NewLRUCache(/*capacity=*/kCacheSize, /*num_shard_bits=*/1,
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/*strict_capacity_limit=*/false,
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/*high_pri_pool_ratio=*/0);
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std::unique_ptr<HybridRowBlockCacheSimulator> cache_simulator(
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new HybridRowBlockCacheSimulator(
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nullptr, sim_cache, /*insert_blocks_row_kvpair_misses=*/true));
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// The first get request accesses 10 blocks. We should only report 10 accesses
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// and 100% miss.
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for (uint32_t i = 0; i < 10; i++) {
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first_get.block_key = kBlockKeyPrefix + std::to_string(block_id);
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cache_simulator->Access(first_get);
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block_id++;
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}
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ASSERT_EQ(10, cache_simulator->total_accesses());
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ASSERT_EQ(100, cache_simulator->miss_ratio());
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ASSERT_EQ(10, cache_simulator->user_accesses());
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ASSERT_EQ(100, cache_simulator->user_miss_ratio());
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auto handle =
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sim_cache->Lookup(ExtractUserKey(std::to_string(first_get.sst_fd_number) +
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"_" + first_get.referenced_key));
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ASSERT_NE(nullptr, handle);
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sim_cache->Release(handle);
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for (uint32_t i = 100; i < block_id; i++) {
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handle = sim_cache->Lookup(kBlockKeyPrefix + std::to_string(i));
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ASSERT_NE(nullptr, handle);
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sim_cache->Release(handle);
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}
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// The second get request accesses the same key. We should report 15
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// access and 66% miss, 10 misses with 15 accesses.
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// We do not consider these 5 block lookups as misses since the row hits the
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// cache.
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for (uint32_t i = 0; i < 5; i++) {
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second_get.block_key = kBlockKeyPrefix + std::to_string(block_id);
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cache_simulator->Access(second_get);
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block_id++;
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}
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ASSERT_EQ(15, cache_simulator->total_accesses());
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ASSERT_EQ(66, static_cast<uint64_t>(cache_simulator->miss_ratio()));
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ASSERT_EQ(15, cache_simulator->user_accesses());
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ASSERT_EQ(66, static_cast<uint64_t>(cache_simulator->user_miss_ratio()));
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handle = sim_cache->Lookup(std::to_string(second_get.sst_fd_number) + "_" +
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second_get.referenced_key);
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ASSERT_NE(nullptr, handle);
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sim_cache->Release(handle);
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for (uint32_t i = 100; i < block_id; i++) {
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handle = sim_cache->Lookup(kBlockKeyPrefix + std::to_string(i));
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if (i < 110) {
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ASSERT_NE(nullptr, handle) << i;
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sim_cache->Release(handle);
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} else {
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ASSERT_EQ(nullptr, handle) << i;
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}
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}
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// The third get on a different key and does not have a size.
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// This key should not be inserted into the cache.
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for (uint32_t i = 0; i < 5; i++) {
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third_get.block_key = kBlockKeyPrefix + std::to_string(block_id);
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cache_simulator->Access(third_get);
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block_id++;
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}
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ASSERT_EQ(20, cache_simulator->total_accesses());
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ASSERT_EQ(75, static_cast<uint64_t>(cache_simulator->miss_ratio()));
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ASSERT_EQ(20, cache_simulator->user_accesses());
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ASSERT_EQ(75, static_cast<uint64_t>(cache_simulator->user_miss_ratio()));
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// Assert that the third key is not inserted into the cache.
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handle = sim_cache->Lookup(std::to_string(third_get.sst_fd_number) + "_" +
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third_get.referenced_key);
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ASSERT_EQ(nullptr, handle);
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for (uint32_t i = 100; i < block_id; i++) {
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if (i < 110 || i >= 115) {
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handle = sim_cache->Lookup(kBlockKeyPrefix + std::to_string(i));
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ASSERT_NE(nullptr, handle) << i;
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sim_cache->Release(handle);
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} else {
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handle = sim_cache->Lookup(kBlockKeyPrefix + std::to_string(i));
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ASSERT_EQ(nullptr, handle) << i;
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}
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}
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}
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TEST_F(CacheSimulatorTest, HybridRowBlockNoInsertCacheSimulator) {
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uint64_t block_id = 100;
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BlockCacheTraceRecord first_get = GenerateGetRecord(kGetId);
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std::shared_ptr<Cache> sim_cache =
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NewLRUCache(/*capacity=*/kCacheSize, /*num_shard_bits=*/1,
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/*strict_capacity_limit=*/false,
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/*high_pri_pool_ratio=*/0);
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std::unique_ptr<HybridRowBlockCacheSimulator> cache_simulator(
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new HybridRowBlockCacheSimulator(
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nullptr, sim_cache, /*insert_blocks_row_kvpair_misses=*/false));
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for (uint32_t i = 0; i < 9; i++) {
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first_get.block_key = kBlockKeyPrefix + std::to_string(block_id);
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cache_simulator->Access(first_get);
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block_id++;
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}
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auto handle =
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sim_cache->Lookup(ExtractUserKey(std::to_string(first_get.sst_fd_number) +
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"_" + first_get.referenced_key));
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ASSERT_NE(nullptr, handle);
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sim_cache->Release(handle);
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// All blocks are missing from the cache since insert_blocks_row_kvpair_misses
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// is set to false.
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for (uint32_t i = 100; i < block_id; i++) {
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handle = sim_cache->Lookup(kBlockKeyPrefix + std::to_string(i));
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ASSERT_EQ(nullptr, handle);
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}
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}
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TEST_F(CacheSimulatorTest, GhostHybridRowBlockCacheSimulator) {
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std::unique_ptr<GhostCache> ghost_cache(new GhostCache(
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NewLRUCache(/*capacity=*/kGhostCacheSize, /*num_shard_bits=*/1,
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/*strict_capacity_limit=*/false,
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/*high_pri_pool_ratio=*/0)));
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const BlockCacheTraceRecord& first_get = GenerateGetRecord(kGetId);
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const BlockCacheTraceRecord& second_get = GenerateGetRecord(kGetId + 1);
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const BlockCacheTraceRecord& third_get = GenerateGetRecord(kGetId + 2);
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std::unique_ptr<HybridRowBlockCacheSimulator> cache_simulator(
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new HybridRowBlockCacheSimulator(
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std::move(ghost_cache),
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NewLRUCache(/*capacity=*/kCacheSize, /*num_shard_bits=*/1,
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/*strict_capacity_limit=*/false,
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/*high_pri_pool_ratio=*/0),
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/*insert_blocks_row_kvpair_misses=*/false));
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// Two get requests access the same key.
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cache_simulator->Access(first_get);
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cache_simulator->Access(second_get);
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ASSERT_EQ(2, cache_simulator->total_accesses());
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ASSERT_EQ(100, cache_simulator->miss_ratio());
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ASSERT_EQ(2, cache_simulator->user_accesses());
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ASSERT_EQ(100, cache_simulator->user_miss_ratio());
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// We insert the key-value pair upon the second get request. A third get
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// request should observe a hit.
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for (uint32_t i = 0; i < 10; i++) {
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cache_simulator->Access(third_get);
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}
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ASSERT_EQ(12, cache_simulator->total_accesses());
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ASSERT_EQ(16, static_cast<uint64_t>(cache_simulator->miss_ratio()));
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ASSERT_EQ(12, cache_simulator->user_accesses());
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ASSERT_EQ(16, static_cast<uint64_t>(cache_simulator->user_miss_ratio()));
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}
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} // namespace rocksdb
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int main(int argc, char** argv) {
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::testing::InitGoogleTest(&argc, argv);
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return RUN_ALL_TESTS();
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}
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