Cache simulator: Add a ghost cache for admission control and a hybrid row-block cache. (#5534)
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: b99edda6418a888e94eb40f71ece45d375e234b1main
haoyuhuang
5 years ago
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Facebook Github Bot
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@ -0,0 +1,337 @@ |
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// 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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