filter_bench - a prelim tool for SST filter benchmarking (#5825)
Summary: Example: using the tool before and after PR https://github.com/facebook/rocksdb/issues/5784 shows that the refactoring, presumed performance-neutral, actually sped up SST filters by about 3% to 8% (repeatable result): Before: - Dry run ns/op: 22.4725 - Single filter ns/op: 51.1078 - Random filter ns/op: 120.133 After: + Dry run ns/op: 22.2301 + Single filter run ns/op: 47.4313 + Random filter ns/op: 115.9 Only tests filters for the block-based table (full filters and partitioned filters - same implementation; not block-based filters), which seems to be the recommended format/implementation. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5825 Differential Revision: D17804987 Pulled By: pdillinger fbshipit-source-id: 0f18a9c254c57f7866030d03e7fa4ba503bac3c5main
Peter Dillinger
5 years ago
committed by
Facebook Github Bot
parent
457bcfde02
commit
46ca51d430
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// Copyright (c) 2019-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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#pragma once |
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#include "table/block_based/block_based_filter_block.h" |
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#include "rocksdb/filter_policy.h" |
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#include "table/block_based/block_based_table_reader.h" |
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namespace rocksdb { |
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namespace mock { |
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class MockBlockBasedTable : public BlockBasedTable { |
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public: |
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explicit MockBlockBasedTable(Rep* rep) |
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: BlockBasedTable(rep, nullptr /* block_cache_tracer */) {} |
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}; |
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class MockBlockBasedTableTester { |
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public: |
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Options options_; |
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ImmutableCFOptions ioptions_; |
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EnvOptions env_options_; |
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BlockBasedTableOptions table_options_; |
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InternalKeyComparator icomp_; |
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std::unique_ptr<BlockBasedTable> table_; |
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MockBlockBasedTableTester(const FilterPolicy *filter_policy) |
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: ioptions_(options_), |
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env_options_(options_), |
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icomp_(options_.comparator) { |
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table_options_.filter_policy.reset(filter_policy); |
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constexpr bool skip_filters = false; |
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constexpr int level = 0; |
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constexpr bool immortal_table = false; |
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table_.reset(new MockBlockBasedTable( |
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new BlockBasedTable::Rep(ioptions_, env_options_, table_options_, |
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icomp_, skip_filters, level, immortal_table))); |
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} |
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}; |
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} // namespace mock
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} // namespace rocksdb
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@ -0,0 +1,461 @@ |
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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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#ifndef GFLAGS |
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#include <cstdio> |
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int main() { |
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fprintf(stderr, "Please install gflags to run rocksdb tools\n"); |
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return 1; |
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} |
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#else |
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#include <cinttypes> |
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#include <iostream> |
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#include <random> |
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#include <vector> |
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#include "port/port.h" |
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#include "port/stack_trace.h" |
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#include "rocksdb/filter_policy.h" |
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#include "table/block_based/full_filter_block.h" |
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#include "table/block_based/mock_block_based_table.h" |
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#include "util/gflags_compat.h" |
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#include "util/hash.h" |
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#include "util/stop_watch.h" |
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using GFLAGS_NAMESPACE::ParseCommandLineFlags; |
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using GFLAGS_NAMESPACE::RegisterFlagValidator; |
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using GFLAGS_NAMESPACE::SetUsageMessage; |
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DEFINE_int64(seed, 0, "Seed for random number generators"); |
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DEFINE_double(working_mem_size_mb, 200, |
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"MB of memory to get up to among all filters"); |
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DEFINE_uint32(average_keys_per_filter, 10000, |
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"Average number of keys per filter"); |
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DEFINE_uint32(key_size, 16, "Number of bytes each key should be"); |
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DEFINE_uint32(batch_size, 8, "Number of keys to group in each batch"); |
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DEFINE_uint32(bits_per_key, 10, "Bits per key setting for filters"); |
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DEFINE_double(m_queries, 200, "Millions of queries for each test mode"); |
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DEFINE_bool(use_full_block_reader, false, |
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"Use FullFilterBlockReader interface rather than FilterBitsReader"); |
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DEFINE_bool(quick, false, "Run more limited set of tests, fewer queries"); |
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DEFINE_bool(allow_bad_fp_rate, false, "Continue even if FP rate is bad"); |
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DEFINE_bool(legend, false, |
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"Print more information about interpreting results instead of " |
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"running tests"); |
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void _always_assert_fail(int line, const char *file, const char *expr) { |
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fprintf(stderr, "%s: %d: Assertion %s failed\n", file, line, expr); |
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abort(); |
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} |
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#define ALWAYS_ASSERT(cond) \ |
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((cond) ? (void)0 : ::_always_assert_fail(__LINE__, __FILE__, #cond)) |
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using rocksdb::BlockContents; |
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using rocksdb::CachableEntry; |
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using rocksdb::fastrange32; |
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using rocksdb::FilterBitsBuilder; |
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using rocksdb::FilterBitsReader; |
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using rocksdb::FullFilterBlockReader; |
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using rocksdb::Slice; |
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using rocksdb::mock::MockBlockBasedTableTester; |
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struct KeyMaker { |
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KeyMaker(size_t size) |
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: data_(new char[size]), |
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slice_(data_.get(), size), |
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vals_(reinterpret_cast<uint32_t *>(data_.get())) { |
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assert(size >= 8); |
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memset(data_.get(), 0, size); |
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} |
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std::unique_ptr<char[]> data_; |
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Slice slice_; |
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uint32_t *vals_; |
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Slice Get(uint32_t filter_num, uint32_t val_num) { |
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vals_[0] = filter_num + val_num; |
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vals_[1] = val_num; |
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return slice_; |
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} |
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}; |
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void PrintWarnings() { |
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#if defined(__GNUC__) && !defined(__OPTIMIZE__) |
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fprintf(stdout, |
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"WARNING: Optimization is disabled: benchmarks unnecessarily slow\n"); |
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#endif |
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#ifndef NDEBUG |
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fprintf(stdout, |
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"WARNING: Assertions are enabled; benchmarks unnecessarily slow\n"); |
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#endif |
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} |
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struct FilterInfo { |
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uint32_t filter_id_ = 0; |
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std::unique_ptr<const char[]> owner_; |
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Slice filter_; |
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uint32_t keys_added_ = 0; |
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std::unique_ptr<FilterBitsReader> reader_; |
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std::unique_ptr<FullFilterBlockReader> full_block_reader_; |
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uint64_t outside_queries_ = 0; |
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uint64_t false_positives_ = 0; |
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}; |
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enum TestMode { |
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kSingleFilter, |
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kBatchPrepared, |
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kBatchUnprepared, |
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kFiftyOneFilter, |
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kEightyTwentyFilter, |
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kRandomFilter, |
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}; |
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static const std::vector<TestMode> allTestModes = { |
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kSingleFilter, kBatchPrepared, kBatchUnprepared, |
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kFiftyOneFilter, kEightyTwentyFilter, kRandomFilter, |
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}; |
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static const std::vector<TestMode> quickTestModes = { |
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kSingleFilter, |
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kRandomFilter, |
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}; |
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const char *TestModeToString(TestMode tm) { |
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switch (tm) { |
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case kSingleFilter: |
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return "Single filter"; |
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case kBatchPrepared: |
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return "Batched, prepared"; |
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case kBatchUnprepared: |
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return "Batched, unprepared"; |
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case kFiftyOneFilter: |
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return "Skewed 50% in 1%"; |
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case kEightyTwentyFilter: |
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return "Skewed 80% in 20%"; |
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case kRandomFilter: |
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return "Random filter"; |
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} |
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return "Bad TestMode"; |
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} |
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struct FilterBench : public MockBlockBasedTableTester { |
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std::vector<KeyMaker> kms_; |
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std::vector<FilterInfo> infos_; |
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std::mt19937 random_; |
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FilterBench() |
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: MockBlockBasedTableTester( |
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rocksdb::NewBloomFilterPolicy(FLAGS_bits_per_key)), |
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random_(FLAGS_seed) { |
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for (uint32_t i = 0; i < FLAGS_batch_size; ++i) { |
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kms_.emplace_back(FLAGS_key_size < 8 ? 8 : FLAGS_key_size); |
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} |
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} |
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void Go(); |
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void RandomQueryTest(bool inside, bool dry_run, TestMode mode); |
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}; |
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void FilterBench::Go() { |
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std::unique_ptr<FilterBitsBuilder> builder( |
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table_options_.filter_policy->GetFilterBitsBuilder()); |
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uint32_t variance_mask = 1; |
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while (variance_mask * variance_mask * 4 < FLAGS_average_keys_per_filter) { |
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variance_mask = variance_mask * 2 + 1; |
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} |
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const std::vector<TestMode> &testModes = |
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FLAGS_quick ? quickTestModes : allTestModes; |
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if (FLAGS_quick) { |
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FLAGS_m_queries /= 10.0; |
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} |
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std::cout << "Building..." << std::endl; |
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size_t total_memory_used = 0; |
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size_t total_keys_added = 0; |
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rocksdb::StopWatchNano timer(rocksdb::Env::Default(), true); |
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while (total_memory_used < 1024 * 1024 * FLAGS_working_mem_size_mb) { |
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uint32_t filter_id = random_(); |
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uint32_t keys_to_add = FLAGS_average_keys_per_filter + |
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(random_() & variance_mask) - (variance_mask / 2); |
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for (uint32_t i = 0; i < keys_to_add; ++i) { |
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builder->AddKey(kms_[0].Get(filter_id, i)); |
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} |
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infos_.emplace_back(); |
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FilterInfo &info = infos_.back(); |
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info.filter_id_ = filter_id; |
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info.filter_ = builder->Finish(&info.owner_); |
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info.keys_added_ = keys_to_add; |
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info.reader_.reset( |
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table_options_.filter_policy->GetFilterBitsReader(info.filter_)); |
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CachableEntry<BlockContents> block( |
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new BlockContents(info.filter_), nullptr /* cache */, |
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nullptr /* cache_handle */, true /* own_value */); |
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info.full_block_reader_.reset( |
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new FullFilterBlockReader(table_.get(), std::move(block))); |
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total_memory_used += info.filter_.size(); |
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total_keys_added += keys_to_add; |
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} |
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uint64_t elapsed_nanos = timer.ElapsedNanos(); |
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double ns = double(elapsed_nanos) / total_keys_added; |
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std::cout << "Build avg ns/key: " << ns << std::endl; |
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std::cout << "Number of filters: " << infos_.size() << std::endl; |
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std::cout << "Total memory (MB): " << total_memory_used / 1024.0 / 1024.0 |
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<< std::endl; |
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double bpk = total_memory_used * 8.0 / total_keys_added; |
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std::cout << "Bits/key actual: " << bpk << std::endl; |
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if (!FLAGS_quick) { |
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double tolerable_rate = std::pow(2.0, -(bpk - 1.0) / (1.4 + bpk / 50.0)); |
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std::cout << "Best possible FP rate %: " << 100.0 * std::pow(2.0, -bpk) |
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<< std::endl; |
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std::cout << "Tolerable FP rate %: " << 100.0 * tolerable_rate << std::endl; |
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std::cout << "----------------------------" << std::endl; |
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std::cout << "Verifying..." << std::endl; |
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uint32_t outside_q_per_f = 1000000 / infos_.size(); |
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uint64_t fps = 0; |
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for (uint32_t i = 0; i < infos_.size(); ++i) { |
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FilterInfo &info = infos_[i]; |
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for (uint32_t j = 0; j < info.keys_added_; ++j) { |
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ALWAYS_ASSERT(info.reader_->MayMatch(kms_[0].Get(info.filter_id_, j))); |
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} |
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for (uint32_t j = 0; j < outside_q_per_f; ++j) { |
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fps += info.reader_->MayMatch( |
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kms_[0].Get(info.filter_id_, j | 0x80000000)); |
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} |
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} |
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std::cout << " No FNs :)" << std::endl; |
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double prelim_rate = double(fps) / outside_q_per_f / infos_.size(); |
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std::cout << " Prelim FP rate %: " << (100.0 * prelim_rate) << std::endl; |
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if (!FLAGS_allow_bad_fp_rate) { |
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ALWAYS_ASSERT(prelim_rate < tolerable_rate); |
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} |
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} |
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std::cout << "----------------------------" << std::endl; |
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std::cout << "Inside queries..." << std::endl; |
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random_.seed(FLAGS_seed + 1); |
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RandomQueryTest(/*inside*/ true, /*dry_run*/ true, kRandomFilter); |
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for (TestMode tm : testModes) { |
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random_.seed(FLAGS_seed + 1); |
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RandomQueryTest(/*inside*/ true, /*dry_run*/ false, tm); |
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} |
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std::cout << "----------------------------" << std::endl; |
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std::cout << "Outside queries..." << std::endl; |
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random_.seed(FLAGS_seed + 2); |
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RandomQueryTest(/*inside*/ false, /*dry_run*/ true, kRandomFilter); |
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for (TestMode tm : testModes) { |
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random_.seed(FLAGS_seed + 2); |
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RandomQueryTest(/*inside*/ false, /*dry_run*/ false, tm); |
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} |
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std::cout << "----------------------------" << std::endl; |
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std::cout << "Done. (For more info, run with -legend or -help.)" << std::endl; |
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} |
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void FilterBench::RandomQueryTest(bool inside, bool dry_run, TestMode mode) { |
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for (auto &info : infos_) { |
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info.outside_queries_ = 0; |
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info.false_positives_ = 0; |
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} |
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uint32_t dry_run_hash = 0; |
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uint64_t max_queries = |
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static_cast<uint64_t>(FLAGS_m_queries * 1000000 + 0.50); |
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// Some filters may be considered secondary in order to implement skewed
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// queries. num_primary_filters is the number that are to be treated as
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// equal, and any remainder will be treated as secondary.
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size_t num_primary_filters = infos_.size(); |
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// The proportion (when divided by 2^32 - 1) of filter queries going to
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// the primary filters (default = all). The remainder of queries are
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// against secondary filters.
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uint32_t primary_filter_threshold = 0xffffffff; |
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if (mode == kSingleFilter) { |
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// 100% of queries to 1 filter
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num_primary_filters = 1; |
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} else if (mode == kFiftyOneFilter) { |
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// 50% of queries
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primary_filter_threshold /= 2; |
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// to 1% of filters
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num_primary_filters = (num_primary_filters + 99) / 100; |
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} else if (mode == kEightyTwentyFilter) { |
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// 80% of queries
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primary_filter_threshold = primary_filter_threshold / 5 * 4; |
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// to 20% of filters
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num_primary_filters = (num_primary_filters + 4) / 5; |
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} |
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size_t batch_size = 1; |
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std::unique_ptr<Slice *[]> batch_slices; |
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std::unique_ptr<bool[]> batch_results; |
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if (mode == kBatchPrepared || mode == kBatchUnprepared) { |
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batch_size = kms_.size(); |
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batch_slices.reset(new Slice *[batch_size]); |
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batch_results.reset(new bool[batch_size]); |
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for (size_t i = 0; i < batch_size; ++i) { |
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batch_slices[i] = &kms_[i].slice_; |
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batch_results[i] = false; |
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} |
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} |
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rocksdb::StopWatchNano timer(rocksdb::Env::Default(), true); |
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for (uint64_t q = 0; q < max_queries; q += batch_size) { |
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uint32_t filter_index; |
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if (random_() <= primary_filter_threshold) { |
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filter_index = fastrange32(num_primary_filters, random_()); |
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} else { |
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// secondary
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filter_index = |
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num_primary_filters + |
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fastrange32(infos_.size() - num_primary_filters, random_()); |
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} |
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FilterInfo &info = infos_[filter_index]; |
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for (size_t i = 0; i < batch_size; ++i) { |
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if (inside) { |
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kms_[i].Get(info.filter_id_, fastrange32(info.keys_added_, random_())); |
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} else { |
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kms_[i].Get(info.filter_id_, random_() | 0x80000000); |
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info.outside_queries_++; |
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} |
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} |
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// TODO: implement batched interface to full block reader
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if (mode == kBatchPrepared && !dry_run && !FLAGS_use_full_block_reader) { |
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for (size_t i = 0; i < batch_size; ++i) { |
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batch_results[i] = false; |
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} |
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info.reader_->MayMatch(batch_size, batch_slices.get(), |
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batch_results.get()); |
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for (size_t i = 0; i < batch_size; ++i) { |
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if (inside) { |
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ALWAYS_ASSERT(batch_results[i]); |
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} else { |
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info.false_positives_ += batch_results[i]; |
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} |
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} |
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} else { |
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for (size_t i = 0; i < batch_size; ++i) { |
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if (dry_run) { |
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dry_run_hash ^= rocksdb::BloomHash(kms_[i].slice_); |
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} else { |
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bool may_match; |
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if (FLAGS_use_full_block_reader) { |
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may_match = info.full_block_reader_->KeyMayMatch( |
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kms_[i].slice_, |
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/*prefix_extractor=*/nullptr, |
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/*block_offset=*/rocksdb::kNotValid, |
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/*no_io=*/false, /*const_ikey_ptr=*/nullptr, |
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/*get_context=*/nullptr, |
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/*lookup_context=*/nullptr); |
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} else { |
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may_match = info.reader_->MayMatch(kms_[i].slice_); |
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} |
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if (inside) { |
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ALWAYS_ASSERT(may_match); |
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} else { |
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info.false_positives_ += may_match; |
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} |
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} |
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} |
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} |
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} |
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uint64_t elapsed_nanos = timer.ElapsedNanos(); |
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double ns = double(elapsed_nanos) / max_queries; |
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if (dry_run) { |
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// Printing part of hash prevents dry run components from being optimized
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// away by compiler
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std::cout << " Dry run (" << std::hex << (dry_run_hash & 0xfff) << std::dec |
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<< ") "; |
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} else { |
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std::cout << " " << TestModeToString(mode) << " "; |
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} |
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std::cout << "ns/op: " << ns << std::endl; |
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if (!inside && !dry_run && mode == kRandomFilter) { |
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uint64_t q = 0; |
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uint64_t fp = 0; |
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double worst_fp_rate = 0.0; |
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double best_fp_rate = 1.0; |
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for (auto &info : infos_) { |
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q += info.outside_queries_; |
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fp += info.false_positives_; |
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if (info.outside_queries_ > 0) { |
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double fp_rate = double(info.false_positives_) / info.outside_queries_; |
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worst_fp_rate = std::max(worst_fp_rate, fp_rate); |
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best_fp_rate = std::min(best_fp_rate, fp_rate); |
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} |
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} |
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std::cout << " Average FP rate %: " << 100.0 * fp / q << std::endl; |
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if (!FLAGS_quick) { |
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std::cout << " Worst FP rate %: " << 100.0 * worst_fp_rate |
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<< std::endl; |
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std::cout << " Best FP rate %: " << 100.0 * best_fp_rate |
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<< std::endl; |
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std::cout << " Best possible bits/key: " |
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<< -std::log(double(fp) / q) / std::log(2.0) << std::endl; |
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} |
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} |
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} |
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int main(int argc, char **argv) { |
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rocksdb::port::InstallStackTraceHandler(); |
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SetUsageMessage(std::string("\nUSAGE:\n") + std::string(argv[0]) + |
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" [-quick] [OTHER OPTIONS]..."); |
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ParseCommandLineFlags(&argc, &argv, true); |
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PrintWarnings(); |
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if (FLAGS_legend) { |
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std::cout |
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<< "Legend:" << std::endl |
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<< " \"Inside\" - key that was added to filter" << std::endl |
||||
<< " \"Outside\" - key that was not added to filter" << std::endl |
||||
<< " \"FN\" - false negative query (must not happen)" << std::endl |
||||
<< " \"FP\" - false positive query (OK at low rate)" << std::endl |
||||
<< " \"Dry run\" - cost of testing and hashing overhead. Consider" |
||||
<< "\n subtracting this cost from the others." << std::endl |
||||
<< " \"Single filter\" - essentially minimum cost, assuming filter" |
||||
<< "\n fits easily in L1 CPU cache." << std::endl |
||||
<< " \"Batched, prepared\" - several queries at once against a" |
||||
<< "\n randomly chosen filter, using multi-query interface." |
||||
<< std::endl |
||||
<< " \"Batched, unprepared\" - similar, but using serial calls" |
||||
<< "\n to single query interface." << std::endl |
||||
<< " \"Random filter\" - a filter is chosen at random as target" |
||||
<< "\n of each query." << std::endl |
||||
<< " \"Skewed X% in Y%\" - like \"Random filter\" except Y% of" |
||||
<< "\n the filters are designated as \"hot\" and receive X%" |
||||
<< "\n of queries." << std::endl; |
||||
} else { |
||||
FilterBench b; |
||||
b.Go(); |
||||
} |
||||
|
||||
return 0; |
||||
} |
||||
|
||||
#endif // GFLAGS
|
||||
Loading…
Reference in new issue