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rocksdb/tools/block_cache_trace_analyzer.cc

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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#ifndef ROCKSDB_LITE
#ifdef GFLAGS
#include "tools/block_cache_trace_analyzer.h"
#include <cinttypes>
#include <fstream>
#include <iomanip>
#include <iostream>
#include <sstream>
#include "monitoring/histogram.h"
#include "util/gflags_compat.h"
#include "util/string_util.h"
using GFLAGS_NAMESPACE::ParseCommandLineFlags;
DEFINE_string(block_cache_trace_path, "", "The trace file path.");
DEFINE_string(
block_cache_sim_config_path, "",
"The config file path. One cache configuration per line. The format of a "
"cache configuration is "
"cache_name,num_shard_bits,cache_capacity_1,...,cache_capacity_N. "
"cache_name is lru. cache_capacity can be xK, xM or xG "
"where x is a positive number.");
DEFINE_int32(block_cache_trace_downsample_ratio, 1,
"The trace collected accesses on one in every "
"block_cache_trace_downsample_ratio blocks. We scale "
"down the simulated cache size by this ratio.");
DEFINE_bool(print_block_size_stats, false,
"Print block size distribution and the distribution break down by "
"block type and column family.");
DEFINE_bool(print_access_count_stats, false,
"Print access count distribution and the distribution break down "
"by block type and column family.");
DEFINE_bool(print_data_block_access_count_stats, false,
"Print data block accesses by user Get and Multi-Get.");
DEFINE_int32(cache_sim_warmup_seconds, 0,
"The number of seconds to warmup simulated caches. The hit/miss "
"counters are reset after the warmup completes.");
DEFINE_string(
block_cache_analysis_result_dir, "",
"The directory that saves block cache analysis results. It contains 1) a "
"mrc file that saves the computed miss ratios for simulated caches. Its "
"format is "
"cache_name,num_shard_bits,capacity,miss_ratio,total_accesses. 2) Several "
"\"label_access_timeline\" files that contain number of accesses per "
"second grouped by the label. File format: "
"time,label_1_access_per_second,label_2_access_per_second,...,label_N_"
"access_per_second where N is the number of unique labels found in the "
"trace. 3) Several \"label_reuse_distance\" and \"label_reuse_interval\" "
"csv files that contain the reuse distance/interval grouped by label. File "
"format: bucket,label_1,label_2,...,label_N. The first N buckets are "
"absolute values. The second N buckets are percentage values.");
DEFINE_string(
timeline_labels, "",
"Group the number of accesses per block per second using these labels. "
"Possible labels are a combination of the following: cf (column family), "
"sst, level, bt (block type), caller, block. For example, label \"cf_bt\" "
"means the number of acccess per second is grouped by unique pairs of "
"\"cf_bt\". A label \"all\" contains the aggregated number of accesses per "
"second across all possible labels.");
DEFINE_string(reuse_distance_labels, "",
"Group the reuse distance of a block using these labels. Reuse "
"distance is defined as the cumulated size of unique blocks read "
"between two consecutive accesses on the same block.");
DEFINE_string(
reuse_distance_buckets, "",
"Group blocks by their reuse distances given these buckets. For "
"example, if 'reuse_distance_buckets' is '1K,1M,1G', we will "
"create four buckets. The first three buckets contain the number of "
"blocks with reuse distance less than 1KB, between 1K and 1M, between 1M "
"and 1G, respectively. The last bucket contains the number of blocks with "
"reuse distance larger than 1G. ");
DEFINE_string(
reuse_interval_labels, "",
"Group the reuse interval of a block using these labels. Reuse "
"interval is defined as the time between two consecutive accesses "
"on the same block.");
DEFINE_string(
reuse_interval_buckets, "",
"Group blocks by their reuse interval given these buckets. For "
"example, if 'reuse_distance_buckets' is '1,10,100', we will "
"create four buckets. The first three buckets contain the number of "
"blocks with reuse interval less than 1 second, between 1 second and 10 "
"seconds, between 10 seconds and 100 seconds, respectively. The last "
"bucket contains the number of blocks with reuse interval longer than 100 "
"seconds.");
namespace rocksdb {
namespace {
const std::string kMissRatioCurveFileName = "mrc";
const std::string kGroupbyBlock = "block";
const std::string kGroupbyColumnFamily = "cf";
const std::string kGroupbySSTFile = "sst";
const std::string kGroupbyBlockType = "bt";
const std::string kGroupbyCaller = "caller";
const std::string kGroupbyLevel = "level";
const std::string kGroupbyAll = "all";
const std::set<std::string> kGroupbyLabels{
kGroupbyBlock, kGroupbyColumnFamily, kGroupbySSTFile, kGroupbyLevel,
kGroupbyBlockType, kGroupbyCaller, kGroupbyAll};
std::string block_type_to_string(TraceType type) {
switch (type) {
case kBlockTraceFilterBlock:
return "Filter";
case kBlockTraceDataBlock:
return "Data";
case kBlockTraceIndexBlock:
return "Index";
case kBlockTraceRangeDeletionBlock:
return "RangeDeletion";
case kBlockTraceUncompressionDictBlock:
return "UncompressionDict";
default:
break;
}
// This cannot happen.
return "InvalidType";
}
std::string caller_to_string(TableReaderCaller caller) {
switch (caller) {
case kUserGet:
return "Get";
case kUserMultiGet:
return "MultiGet";
case kUserIterator:
return "Iterator";
case kUserApproximateSize:
return "ApproximateSize";
case kUserVerifyChecksum:
return "VerifyChecksum";
case kSSTDumpTool:
return "SSTDumpTool";
case kExternalSSTIngestion:
return "ExternalSSTIngestion";
case kRepair:
return "Repair";
case kPrefetch:
return "Prefetch";
case kCompaction:
return "Compaction";
case kCompactionRefill:
return "CompactionRefill";
case kFlush:
return "Flush";
case kSSTFileReader:
return "SSTFileReader";
case kUncategorized:
return "Uncategorized";
default:
break;
}
// This cannot happen.
return "InvalidCaller";
}
const char kBreakLine[] =
"***************************************************************\n";
void print_break_lines(uint32_t num_break_lines) {
for (uint32_t i = 0; i < num_break_lines; i++) {
fprintf(stdout, kBreakLine);
}
}
double percent(uint64_t numerator, uint64_t denomenator) {
if (denomenator == 0) {
return -1;
}
return static_cast<double>(numerator * 100.0 / denomenator);
}
} // namespace
BlockCacheTraceSimulator::BlockCacheTraceSimulator(
uint64_t warmup_seconds, uint32_t downsample_ratio,
const std::vector<CacheConfiguration>& cache_configurations)
: warmup_seconds_(warmup_seconds),
downsample_ratio_(downsample_ratio),
cache_configurations_(cache_configurations) {
for (auto const& config : cache_configurations_) {
for (auto cache_capacity : config.cache_capacities) {
// Scale down the cache capacity since the trace contains accesses on
// 1/'downsample_ratio' blocks.
uint64_t simulate_cache_capacity =
cache_capacity / downsample_ratio_;
sim_caches_.push_back(NewSimCache(
NewLRUCache(simulate_cache_capacity, config.num_shard_bits),
/*real_cache=*/nullptr, config.num_shard_bits));
}
}
}
void BlockCacheTraceSimulator::Access(const BlockCacheTraceRecord& access) {
if (trace_start_time_ == 0) {
trace_start_time_ = access.access_timestamp;
}
// access.access_timestamp is in microseconds.
if (!warmup_complete_ &&
trace_start_time_ + warmup_seconds_ * kMicrosInSecond <=
access.access_timestamp) {
for (auto& sim_cache : sim_caches_) {
sim_cache->reset_counter();
}
warmup_complete_ = true;
}
for (auto& sim_cache : sim_caches_) {
auto handle = sim_cache->Lookup(access.block_key);
if (handle == nullptr && !access.no_insert) {
sim_cache->Insert(access.block_key, /*value=*/nullptr, access.block_size,
/*deleter=*/nullptr);
}
}
}
void BlockCacheTraceAnalyzer::WriteMissRatioCurves() const {
if (!cache_simulator_) {
return;
}
if (output_dir_.empty()) {
return;
}
const std::string output_miss_ratio_curve_path =
output_dir_ + "/" + kMissRatioCurveFileName;
std::ofstream out(output_miss_ratio_curve_path);
if (!out.is_open()) {
return;
}
// Write header.
const std::string header =
"cache_name,num_shard_bits,capacity,miss_ratio,total_accesses";
out << header << std::endl;
uint64_t sim_cache_index = 0;
for (auto const& config : cache_simulator_->cache_configurations()) {
for (auto cache_capacity : config.cache_capacities) {
uint64_t hits =
cache_simulator_->sim_caches()[sim_cache_index]->get_hit_counter();
uint64_t misses =
cache_simulator_->sim_caches()[sim_cache_index]->get_miss_counter();
uint64_t total_accesses = hits + misses;
double miss_ratio = static_cast<double>(misses * 100.0 / total_accesses);
// Write the body.
out << config.cache_name;
out << ",";
out << config.num_shard_bits;
out << ",";
out << cache_capacity;
out << ",";
out << std::fixed << std::setprecision(4) << miss_ratio;
out << ",";
out << total_accesses;
out << std::endl;
sim_cache_index++;
}
}
out.close();
}
std::set<std::string> BlockCacheTraceAnalyzer::ParseLabelStr(
const std::string& label_str) const {
std::stringstream ss(label_str);
std::set<std::string> labels;
// label_str is in the form of "label1_label2_label3", e.g., cf_bt.
while (ss.good()) {
std::string label_name;
getline(ss, label_name, '_');
if (kGroupbyLabels.find(label_name) == kGroupbyLabels.end()) {
// Unknown label name.
fprintf(stderr, "Unknown label name %s, label string %s\n",
label_name.c_str(), label_str.c_str());
return {};
}
labels.insert(label_name);
}
return labels;
}
std::string BlockCacheTraceAnalyzer::BuildLabel(
const std::set<std::string>& labels, const std::string& cf_name,
uint64_t fd, uint32_t level, TraceType type, TableReaderCaller caller,
const std::string& block_key) const {
std::map<std::string, std::string> label_value_map;
label_value_map[kGroupbyAll] = kGroupbyAll;
label_value_map[kGroupbyLevel] = std::to_string(level);
label_value_map[kGroupbyCaller] = caller_to_string(caller);
label_value_map[kGroupbySSTFile] = std::to_string(fd);
label_value_map[kGroupbyBlockType] = block_type_to_string(type);
label_value_map[kGroupbyColumnFamily] = cf_name;
label_value_map[kGroupbyBlock] = block_key;
// Concatenate the label values.
std::string label;
for (auto const& l : labels) {
label += label_value_map[l];
label += "-";
}
if (!label.empty()) {
label.pop_back();
}
return label;
}
void BlockCacheTraceAnalyzer::WriteAccessTimeline(
const std::string& label_str) const {
std::set<std::string> labels = ParseLabelStr(label_str);
uint64_t start_time = port::kMaxUint64;
uint64_t end_time = 0;
std::map<std::string, std::map<uint64_t, uint64_t>> label_access_timeline;
for (auto const& cf_aggregates : cf_aggregates_map_) {
// Stats per column family.
const std::string& cf_name = cf_aggregates.first;
for (auto const& file_aggregates : cf_aggregates.second.fd_aggregates_map) {
// Stats per SST file.
const uint64_t fd = file_aggregates.first;
const uint32_t level = file_aggregates.second.level;
for (auto const& block_type_aggregates :
file_aggregates.second.block_type_aggregates_map) {
// Stats per block type.
const TraceType type = block_type_aggregates.first;
for (auto const& block_access_info :
block_type_aggregates.second.block_access_info_map) {
// Stats per block.
for (auto const& timeline :
block_access_info.second.caller_num_accesses_timeline) {
const TableReaderCaller caller = timeline.first;
const std::string& block_key = block_access_info.first;
const std::string label =
BuildLabel(labels, cf_name, fd, level, type, caller, block_key);
for (auto const& naccess : timeline.second) {
const uint64_t timestamp = naccess.first;
const uint64_t num = naccess.second;
label_access_timeline[label][timestamp] += num;
start_time = std::min(start_time, timestamp);
end_time = std::max(end_time, timestamp);
}
}
}
}
}
}
// We have label_access_timeline now. Write them into a file.
const std::string output_path =
output_dir_ + "/" + label_str + "_access_timeline";
std::ofstream out(output_path);
if (!out.is_open()) {
return;
}
std::string header("time");
for (auto const& label : label_access_timeline) {
header += ",";
header += label.first;
}
out << header << std::endl;
std::string row;
for (uint64_t now = start_time; now <= end_time; now++) {
row = std::to_string(now);
for (auto const& label : label_access_timeline) {
auto it = label.second.find(now);
row += ",";
if (it != label.second.end()) {
row += std::to_string(it->second);
} else {
row += "0";
}
}
out << row << std::endl;
}
out.close();
}
void BlockCacheTraceAnalyzer::WriteReuseDistance(
const std::string& label_str,
const std::set<uint64_t>& distance_buckets) const {
std::set<std::string> labels = ParseLabelStr(label_str);
std::map<std::string, std::map<uint64_t, uint64_t>> label_distance_num_reuses;
uint64_t total_num_reuses = 0;
for (auto const& cf_aggregates : cf_aggregates_map_) {
// Stats per column family.
const std::string& cf_name = cf_aggregates.first;
for (auto const& file_aggregates : cf_aggregates.second.fd_aggregates_map) {
// Stats per SST file.
const uint64_t fd = file_aggregates.first;
const uint32_t level = file_aggregates.second.level;
for (auto const& block_type_aggregates :
file_aggregates.second.block_type_aggregates_map) {
// Stats per block type.
const TraceType type = block_type_aggregates.first;
for (auto const& block_access_info :
block_type_aggregates.second.block_access_info_map) {
// Stats per block.
const std::string& block_key = block_access_info.first;
const std::string label = BuildLabel(
labels, cf_name, fd, level, type,
TableReaderCaller::kMaxBlockCacheLookupCaller, block_key);
if (label_distance_num_reuses.find(label) ==
label_distance_num_reuses.end()) {
// The first time we encounter this label.
for (auto const& distance_bucket : distance_buckets) {
label_distance_num_reuses[label][distance_bucket] = 0;
}
}
for (auto const& reuse_distance :
block_access_info.second.reuse_distance_count) {
label_distance_num_reuses[label]
.upper_bound(reuse_distance.first)
->second += reuse_distance.second;
total_num_reuses += reuse_distance.second;
}
}
}
}
}
// We have label_naccesses and label_distance_num_reuses now. Write them into
// a file.
const std::string output_path =
output_dir_ + "/" + label_str + "_reuse_distance";
std::ofstream out(output_path);
if (!out.is_open()) {
return;
}
std::string header("bucket");
for (auto const& label_it : label_distance_num_reuses) {
header += ",";
header += label_it.first;
}
out << header << std::endl;
// Absolute values.
for (auto const& bucket : distance_buckets) {
std::string row(std::to_string(bucket));
for (auto const& label_it : label_distance_num_reuses) {
auto const& it = label_it.second.find(bucket);
assert(it != label_it.second.end());
row += ",";
row += std::to_string(it->second);
}
out << row << std::endl;
}
// Percentage values.
for (auto const& bucket : distance_buckets) {
std::string row(std::to_string(bucket));
for (auto const& label_it : label_distance_num_reuses) {
auto const& it = label_it.second.find(bucket);
assert(it != label_it.second.end());
row += ",";
row += std::to_string(percent(it->second, total_num_reuses));
}
out << row << std::endl;
}
out.close();
}
void BlockCacheTraceAnalyzer::UpdateReuseIntervalStats(
const std::string& label, const std::set<uint64_t>& time_buckets,
const std::map<uint64_t, uint64_t> timeline,
std::map<std::string, std::map<uint64_t, uint64_t>>* label_time_num_reuses,
uint64_t* total_num_reuses) const {
assert(label_time_num_reuses);
assert(total_num_reuses);
if (label_time_num_reuses->find(label) == label_time_num_reuses->end()) {
// The first time we encounter this label.
for (auto const& time_bucket : time_buckets) {
(*label_time_num_reuses)[label][time_bucket] = 0;
}
}
auto it = timeline.begin();
const uint64_t prev_timestamp = it->first;
const uint64_t prev_num = it->second;
it++;
// Reused within one second.
if (prev_num > 1) {
(*label_time_num_reuses)[label].upper_bound(1)->second += prev_num - 1;
*total_num_reuses += prev_num - 1;
}
while (it != timeline.end()) {
const uint64_t timestamp = it->first;
const uint64_t num = it->second;
const uint64_t reuse_interval = timestamp - prev_timestamp;
(*label_time_num_reuses)[label].upper_bound(reuse_interval)->second += num;
*total_num_reuses += num;
}
}
void BlockCacheTraceAnalyzer::WriteReuseInterval(
const std::string& label_str,
const std::set<uint64_t>& time_buckets) const {
std::set<std::string> labels = ParseLabelStr(label_str);
std::map<std::string, std::map<uint64_t, uint64_t>> label_time_num_reuses;
uint64_t total_num_reuses = 0;
for (auto const& cf_aggregates : cf_aggregates_map_) {
// Stats per column family.
const std::string& cf_name = cf_aggregates.first;
for (auto const& file_aggregates : cf_aggregates.second.fd_aggregates_map) {
// Stats per SST file.
const uint64_t fd = file_aggregates.first;
const uint32_t level = file_aggregates.second.level;
for (auto const& block_type_aggregates :
file_aggregates.second.block_type_aggregates_map) {
// Stats per block type.
const TraceType type = block_type_aggregates.first;
for (auto const& block_access_info :
block_type_aggregates.second.block_access_info_map) {
// Stats per block.
const std::string& block_key = block_access_info.first;
if (labels.find(kGroupbyCaller) != labels.end()) {
for (auto const& timeline :
block_access_info.second.caller_num_accesses_timeline) {
const TableReaderCaller caller = timeline.first;
const std::string label = BuildLabel(labels, cf_name, fd, level,
type, caller, block_key);
UpdateReuseIntervalStats(label, time_buckets, timeline.second,
&label_time_num_reuses,
&total_num_reuses);
}
continue;
}
// Does not group by caller so we need to flatten the access timeline.
const std::string label = BuildLabel(
labels, cf_name, fd, level, type,
TableReaderCaller::kMaxBlockCacheLookupCaller, block_key);
std::map<uint64_t, uint64_t> timeline;
for (auto const& caller_timeline :
block_access_info.second.caller_num_accesses_timeline) {
for (auto const& time_naccess : caller_timeline.second) {
timeline[time_naccess.first] += time_naccess.second;
}
}
UpdateReuseIntervalStats(label, time_buckets, timeline,
&label_time_num_reuses, &total_num_reuses);
}
}
}
}
// We have label_naccesses and label_interval_num_reuses now. Write them into
// a file.
const std::string output_path =
output_dir_ + "/" + label_str + "_reuse_interval";
std::ofstream out(output_path);
if (!out.is_open()) {
return;
}
std::string header("bucket");
for (auto const& label_it : label_time_num_reuses) {
header += ",";
header += label_it.first;
}
out << header << std::endl;
// Absolute values.
for (auto const& bucket : time_buckets) {
std::string row(std::to_string(bucket));
for (auto const& label_it : label_time_num_reuses) {
auto const& it = label_it.second.find(bucket);
assert(it != label_it.second.end());
row += ",";
row += std::to_string(it->second);
}
out << row << std::endl;
}
// Percentage values.
for (auto const& bucket : time_buckets) {
std::string row(std::to_string(bucket));
for (auto const& label_it : label_time_num_reuses) {
auto const& it = label_it.second.find(bucket);
assert(it != label_it.second.end());
row += ",";
row += std::to_string(percent(it->second, total_num_reuses));
}
out << row << std::endl;
}
out.close();
}
BlockCacheTraceAnalyzer::BlockCacheTraceAnalyzer(
const std::string& trace_file_path, const std::string& output_dir,
std::unique_ptr<BlockCacheTraceSimulator>&& cache_simulator)
: env_(rocksdb::Env::Default()),
trace_file_path_(trace_file_path),
output_dir_(output_dir),
cache_simulator_(std::move(cache_simulator)) {}
void BlockCacheTraceAnalyzer::ComputeReuseDistance(
BlockAccessInfo* info) const {
assert(info);
if (info->num_accesses == 0) {
return;
}
uint64_t reuse_distance = 0;
for (auto const& block_key : info->unique_blocks_since_last_access) {
auto const& it = block_info_map_.find(block_key);
// This block must exist.
assert(it != block_info_map_.end());
reuse_distance += it->second->block_size;
}
info->reuse_distance_count[reuse_distance] += 1;
// We clear this hash set since this is the second access on this block.
info->unique_blocks_since_last_access.clear();
}
void BlockCacheTraceAnalyzer::RecordAccess(
const BlockCacheTraceRecord& access) {
ColumnFamilyAccessInfoAggregate& cf_aggr = cf_aggregates_map_[access.cf_name];
SSTFileAccessInfoAggregate& file_aggr =
cf_aggr.fd_aggregates_map[access.sst_fd_number];
file_aggr.level = access.level;
BlockTypeAccessInfoAggregate& block_type_aggr =
file_aggr.block_type_aggregates_map[access.block_type];
BlockAccessInfo& block_access_info =
block_type_aggr.block_access_info_map[access.block_key];
ComputeReuseDistance(&block_access_info);
block_access_info.AddAccess(access);
block_info_map_[access.block_key] = &block_access_info;
// Add this block to all existing blocks.
for (auto& cf_aggregates : cf_aggregates_map_) {
for (auto& file_aggregates : cf_aggregates.second.fd_aggregates_map) {
for (auto& block_type_aggregates :
file_aggregates.second.block_type_aggregates_map) {
for (auto& existing_block :
block_type_aggregates.second.block_access_info_map) {
existing_block.second.unique_blocks_since_last_access.insert(
access.block_key);
}
}
}
}
}
Status BlockCacheTraceAnalyzer::Analyze() {
std::unique_ptr<TraceReader> trace_reader;
Status s =
NewFileTraceReader(env_, EnvOptions(), trace_file_path_, &trace_reader);
if (!s.ok()) {
return s;
}
BlockCacheTraceReader reader(std::move(trace_reader));
s = reader.ReadHeader(&header_);
if (!s.ok()) {
return s;
}
while (s.ok()) {
BlockCacheTraceRecord access;
s = reader.ReadAccess(&access);
if (!s.ok()) {
return s;
}
RecordAccess(access);
if (cache_simulator_) {
cache_simulator_->Access(access);
}
}
return Status::OK();
}
void BlockCacheTraceAnalyzer::PrintBlockSizeStats() const {
HistogramStat bs_stats;
std::map<TraceType, HistogramStat> bt_stats_map;
std::map<std::string, std::map<TraceType, HistogramStat>> cf_bt_stats_map;
for (auto const& cf_aggregates : cf_aggregates_map_) {
// Stats per column family.
const std::string& cf_name = cf_aggregates.first;
for (auto const& file_aggregates : cf_aggregates.second.fd_aggregates_map) {
// Stats per SST file.
for (auto const& block_type_aggregates :
file_aggregates.second.block_type_aggregates_map) {
// Stats per block type.
const TraceType type = block_type_aggregates.first;
for (auto const& block_access_info :
block_type_aggregates.second.block_access_info_map) {
// Stats per block.
bs_stats.Add(block_access_info.second.block_size);
bt_stats_map[type].Add(block_access_info.second.block_size);
cf_bt_stats_map[cf_name][type].Add(
block_access_info.second.block_size);
}
}
}
}
fprintf(stdout, "Block size stats: \n%s", bs_stats.ToString().c_str());
for (auto const& bt_stats : bt_stats_map) {
print_break_lines(/*num_break_lines=*/1);
fprintf(stdout, "Block size stats for block type %s: \n%s",
block_type_to_string(bt_stats.first).c_str(),
bt_stats.second.ToString().c_str());
}
for (auto const& cf_bt_stats : cf_bt_stats_map) {
const std::string& cf_name = cf_bt_stats.first;
for (auto const& bt_stats : cf_bt_stats.second) {
print_break_lines(/*num_break_lines=*/1);
fprintf(stdout,
"Block size stats for column family %s and block type %s: \n%s",
cf_name.c_str(), block_type_to_string(bt_stats.first).c_str(),
bt_stats.second.ToString().c_str());
}
}
}
void BlockCacheTraceAnalyzer::PrintAccessCountStats() const {
HistogramStat access_stats;
std::map<TraceType, HistogramStat> bt_stats_map;
std::map<std::string, std::map<TraceType, HistogramStat>> cf_bt_stats_map;
for (auto const& cf_aggregates : cf_aggregates_map_) {
// Stats per column family.
const std::string& cf_name = cf_aggregates.first;
for (auto const& file_aggregates : cf_aggregates.second.fd_aggregates_map) {
// Stats per SST file.
for (auto const& block_type_aggregates :
file_aggregates.second.block_type_aggregates_map) {
// Stats per block type.
const TraceType type = block_type_aggregates.first;
for (auto const& block_access_info :
block_type_aggregates.second.block_access_info_map) {
// Stats per block.
access_stats.Add(block_access_info.second.num_accesses);
bt_stats_map[type].Add(block_access_info.second.num_accesses);
cf_bt_stats_map[cf_name][type].Add(
block_access_info.second.num_accesses);
}
}
}
}
fprintf(stdout,
"Block access count stats: The number of accesses per block.\n%s",
access_stats.ToString().c_str());
for (auto const& bt_stats : bt_stats_map) {
print_break_lines(/*num_break_lines=*/1);
fprintf(stdout, "Break down by block type %s: \n%s",
block_type_to_string(bt_stats.first).c_str(),
bt_stats.second.ToString().c_str());
}
for (auto const& cf_bt_stats : cf_bt_stats_map) {
const std::string& cf_name = cf_bt_stats.first;
for (auto const& bt_stats : cf_bt_stats.second) {
print_break_lines(/*num_break_lines=*/1);
fprintf(stdout,
"Break down by column family %s and block type "
"%s: \n%s",
cf_name.c_str(), block_type_to_string(bt_stats.first).c_str(),
bt_stats.second.ToString().c_str());
}
}
}
void BlockCacheTraceAnalyzer::PrintDataBlockAccessStats() const {
HistogramStat existing_keys_stats;
std::map<std::string, HistogramStat> cf_existing_keys_stats_map;
HistogramStat non_existing_keys_stats;
std::map<std::string, HistogramStat> cf_non_existing_keys_stats_map;
HistogramStat block_access_stats;
std::map<std::string, HistogramStat> cf_block_access_info;
HistogramStat percent_referenced_bytes;
std::map<std::string, HistogramStat> cf_percent_referenced_bytes;
// Total number of accesses in a data block / number of keys in a data block.
HistogramStat avg_naccesses_per_key_in_a_data_block;
std::map<std::string, HistogramStat> cf_avg_naccesses_per_key_in_a_data_block;
// The standard deviation on the number of accesses of a key in a data block.
HistogramStat stdev_naccesses_per_key_in_a_data_block;
std::map<std::string, HistogramStat>
cf_stdev_naccesses_per_key_in_a_data_block;
for (auto const& cf_aggregates : cf_aggregates_map_) {
// Stats per column family.
const std::string& cf_name = cf_aggregates.first;
for (auto const& file_aggregates : cf_aggregates.second.fd_aggregates_map) {
// Stats per SST file.
for (auto const& block_type_aggregates :
file_aggregates.second.block_type_aggregates_map) {
// Stats per block type.
for (auto const& block_access_info :
block_type_aggregates.second.block_access_info_map) {
// Stats per block.
if (block_access_info.second.num_keys == 0) {
continue;
}
// Use four decimal points.
uint64_t percent_referenced_for_existing_keys = (uint64_t)(
((double)block_access_info.second.key_num_access_map.size() /
(double)block_access_info.second.num_keys) *
10000.0);
uint64_t percent_referenced_for_non_existing_keys =
(uint64_t)(((double)block_access_info.second
.non_exist_key_num_access_map.size() /
(double)block_access_info.second.num_keys) *
10000.0);
uint64_t percent_accesses_for_existing_keys = (uint64_t)(
((double)
block_access_info.second.num_referenced_key_exist_in_block /
(double)block_access_info.second.num_accesses) *
10000.0);
HistogramStat hist_naccess_per_key;
for (auto const& key_access :
block_access_info.second.key_num_access_map) {
hist_naccess_per_key.Add(key_access.second);
}
uint64_t avg_accesses = hist_naccess_per_key.Average();
uint64_t stdev_accesses = hist_naccess_per_key.StandardDeviation();
avg_naccesses_per_key_in_a_data_block.Add(avg_accesses);
cf_avg_naccesses_per_key_in_a_data_block[cf_name].Add(avg_accesses);
stdev_naccesses_per_key_in_a_data_block.Add(stdev_accesses);
cf_stdev_naccesses_per_key_in_a_data_block[cf_name].Add(
stdev_accesses);
existing_keys_stats.Add(percent_referenced_for_existing_keys);
cf_existing_keys_stats_map[cf_name].Add(
percent_referenced_for_existing_keys);
non_existing_keys_stats.Add(percent_referenced_for_non_existing_keys);
cf_non_existing_keys_stats_map[cf_name].Add(
percent_referenced_for_non_existing_keys);
block_access_stats.Add(percent_accesses_for_existing_keys);
cf_block_access_info[cf_name].Add(percent_accesses_for_existing_keys);
}
}
}
}
fprintf(stdout,
"Histogram on the number of referenced keys existing in a block over "
"the total number of keys in a block: \n%s",
existing_keys_stats.ToString().c_str());
for (auto const& cf_stats : cf_existing_keys_stats_map) {
print_break_lines(/*num_break_lines=*/1);
fprintf(stdout, "Break down by column family %s: \n%s",
cf_stats.first.c_str(), cf_stats.second.ToString().c_str());
}
print_break_lines(/*num_break_lines=*/1);
fprintf(
stdout,
"Histogram on the number of referenced keys DO NOT exist in a block over "
"the total number of keys in a block: \n%s",
non_existing_keys_stats.ToString().c_str());
for (auto const& cf_stats : cf_non_existing_keys_stats_map) {
print_break_lines(/*num_break_lines=*/1);
fprintf(stdout, "Break down by column family %s: \n%s",
cf_stats.first.c_str(), cf_stats.second.ToString().c_str());
}
print_break_lines(/*num_break_lines=*/1);
fprintf(stdout,
"Histogram on the number of accesses on keys exist in a block over "
"the total number of accesses in a block: \n%s",
block_access_stats.ToString().c_str());
for (auto const& cf_stats : cf_block_access_info) {
print_break_lines(/*num_break_lines=*/1);
fprintf(stdout, "Break down by column family %s: \n%s",
cf_stats.first.c_str(), cf_stats.second.ToString().c_str());
}
print_break_lines(/*num_break_lines=*/1);
fprintf(
stdout,
"Histogram on the average number of accesses per key in a block: \n%s",
avg_naccesses_per_key_in_a_data_block.ToString().c_str());
for (auto const& cf_stats : cf_avg_naccesses_per_key_in_a_data_block) {
fprintf(stdout, "Break down by column family %s: \n%s",
cf_stats.first.c_str(), cf_stats.second.ToString().c_str());
}
print_break_lines(/*num_break_lines=*/1);
fprintf(stdout,
"Histogram on the standard deviation of the number of accesses per "
"key in a block: \n%s",
stdev_naccesses_per_key_in_a_data_block.ToString().c_str());
for (auto const& cf_stats : cf_stdev_naccesses_per_key_in_a_data_block) {
fprintf(stdout, "Break down by column family %s: \n%s",
cf_stats.first.c_str(), cf_stats.second.ToString().c_str());
}
}
void BlockCacheTraceAnalyzer::PrintStatsSummary() const {
uint64_t total_num_files = 0;
uint64_t total_num_blocks = 0;
uint64_t total_num_accesses = 0;
std::map<TraceType, uint64_t> bt_num_blocks_map;
std::map<TableReaderCaller, uint64_t> caller_num_access_map;
std::map<TableReaderCaller, std::map<TraceType, uint64_t>>
caller_bt_num_access_map;
std::map<TableReaderCaller, std::map<uint32_t, uint64_t>>
caller_level_num_access_map;
for (auto const& cf_aggregates : cf_aggregates_map_) {
// Stats per column family.
const std::string& cf_name = cf_aggregates.first;
uint64_t cf_num_files = 0;
uint64_t cf_num_blocks = 0;
std::map<TraceType, uint64_t> cf_bt_blocks;
uint64_t cf_num_accesses = 0;
std::map<TableReaderCaller, uint64_t> cf_caller_num_accesses_map;
std::map<TableReaderCaller, std::map<uint64_t, uint64_t>>
cf_caller_level_num_accesses_map;
std::map<TableReaderCaller, std::map<uint64_t, uint64_t>>
cf_caller_file_num_accesses_map;
std::map<TableReaderCaller, std::map<TraceType, uint64_t>>
cf_caller_bt_num_accesses_map;
total_num_files += cf_aggregates.second.fd_aggregates_map.size();
for (auto const& file_aggregates : cf_aggregates.second.fd_aggregates_map) {
// Stats per SST file.
const uint64_t fd = file_aggregates.first;
const uint32_t level = file_aggregates.second.level;
cf_num_files++;
for (auto const& block_type_aggregates :
file_aggregates.second.block_type_aggregates_map) {
// Stats per block type.
const TraceType type = block_type_aggregates.first;
cf_bt_blocks[type] +=
block_type_aggregates.second.block_access_info_map.size();
total_num_blocks +=
block_type_aggregates.second.block_access_info_map.size();
bt_num_blocks_map[type] +=
block_type_aggregates.second.block_access_info_map.size();
for (auto const& block_access_info :
block_type_aggregates.second.block_access_info_map) {
// Stats per block.
cf_num_blocks++;
for (auto const& stats :
block_access_info.second.caller_num_access_map) {
// Stats per caller.
const TableReaderCaller caller = stats.first;
const uint64_t num_accesses = stats.second;
// Overall stats.
total_num_accesses += num_accesses;
caller_num_access_map[caller] += num_accesses;
caller_bt_num_access_map[caller][type] += num_accesses;
caller_level_num_access_map[caller][level] += num_accesses;
// Column Family stats.
cf_num_accesses += num_accesses;
cf_caller_num_accesses_map[caller] += num_accesses;
cf_caller_level_num_accesses_map[caller][level] += num_accesses;
cf_caller_file_num_accesses_map[caller][fd] += num_accesses;
cf_caller_bt_num_accesses_map[caller][type] += num_accesses;
}
}
}
}
// Print stats.
print_break_lines(/*num_break_lines=*/3);
fprintf(stdout, "Statistics for column family %s:\n", cf_name.c_str());
fprintf(stdout,
" Number of files:%" PRIu64 " Number of blocks: %" PRIu64
" Number of accesses: %" PRIu64 "\n",
cf_num_files, cf_num_blocks, cf_num_accesses);
for (auto block_type : cf_bt_blocks) {
fprintf(stdout, "Number of %s blocks: %" PRIu64 " Percent: %.2f\n",
block_type_to_string(block_type.first).c_str(), block_type.second,
percent(block_type.second, cf_num_blocks));
}
for (auto caller : cf_caller_num_accesses_map) {
const uint64_t naccesses = caller.second;
print_break_lines(/*num_break_lines=*/1);
fprintf(stdout,
"Caller %s: Number of accesses %" PRIu64 " Percent: %.2f\n",
caller_to_string(caller.first).c_str(), naccesses,
percent(naccesses, cf_num_accesses));
fprintf(stdout, "Caller %s: Number of accesses per level break down\n",
caller_to_string(caller.first).c_str());
for (auto naccess_level :
cf_caller_level_num_accesses_map[caller.first]) {
fprintf(stdout,
"\t Level %" PRIu64 ": Number of accesses: %" PRIu64
" Percent: %.2f\n",
naccess_level.first, naccess_level.second,
percent(naccess_level.second, naccesses));
}
fprintf(stdout, "Caller %s: Number of accesses per file break down\n",
caller_to_string(caller.first).c_str());
for (auto naccess_file : cf_caller_file_num_accesses_map[caller.first]) {
fprintf(stdout,
"\t File %" PRIu64 ": Number of accesses: %" PRIu64
" Percent: %.2f\n",
naccess_file.first, naccess_file.second,
percent(naccess_file.second, naccesses));
}
fprintf(stdout,
"Caller %s: Number of accesses per block type break down\n",
caller_to_string(caller.first).c_str());
for (auto naccess_type : cf_caller_bt_num_accesses_map[caller.first]) {
fprintf(stdout,
"\t Block Type %s: Number of accesses: %" PRIu64
" Percent: %.2f\n",
block_type_to_string(naccess_type.first).c_str(),
naccess_type.second, percent(naccess_type.second, naccesses));
}
}
}
print_break_lines(/*num_break_lines=*/3);
fprintf(stdout, "Overall statistics:\n");
fprintf(stdout,
"Number of files: %" PRIu64 " Number of blocks: %" PRIu64
" Number of accesses: %" PRIu64 "\n",
total_num_files, total_num_blocks, total_num_accesses);
for (auto block_type : bt_num_blocks_map) {
fprintf(stdout, "Number of %s blocks: %" PRIu64 " Percent: %.2f\n",
block_type_to_string(block_type.first).c_str(), block_type.second,
percent(block_type.second, total_num_blocks));
}
for (auto caller : caller_num_access_map) {
print_break_lines(/*num_break_lines=*/1);
uint64_t naccesses = caller.second;
fprintf(stdout, "Caller %s: Number of accesses %" PRIu64 " Percent: %.2f\n",
caller_to_string(caller.first).c_str(), naccesses,
percent(naccesses, total_num_accesses));
fprintf(stdout, "Caller %s: Number of accesses per level break down\n",
caller_to_string(caller.first).c_str());
for (auto naccess_level : caller_level_num_access_map[caller.first]) {
fprintf(stdout,
"\t Level %d: Number of accesses: %" PRIu64 " Percent: %.2f\n",
naccess_level.first, naccess_level.second,
percent(naccess_level.second, naccesses));
}
fprintf(stdout, "Caller %s: Number of accesses per block type break down\n",
caller_to_string(caller.first).c_str());
for (auto naccess_type : caller_bt_num_access_map[caller.first]) {
fprintf(stdout,
"\t Block Type %s: Number of accesses: %" PRIu64
" Percent: %.2f\n",
block_type_to_string(naccess_type.first).c_str(),
naccess_type.second, percent(naccess_type.second, naccesses));
}
}
}
std::vector<CacheConfiguration> parse_cache_config_file(
const std::string& config_path) {
std::ifstream file(config_path);
if (!file.is_open()) {
return {};
}
std::vector<CacheConfiguration> configs;
std::string line;
while (getline(file, line)) {
CacheConfiguration cache_config;
std::stringstream ss(line);
std::vector<std::string> config_strs;
while (ss.good()) {
std::string substr;
getline(ss, substr, ',');
config_strs.push_back(substr);
}
// Sanity checks.
if (config_strs.size() < 3) {
fprintf(stderr, "Invalid cache simulator configuration %s\n",
line.c_str());
exit(1);
}
if (config_strs[0] != "lru") {
fprintf(stderr, "We only support LRU cache %s\n", line.c_str());
exit(1);
}
cache_config.cache_name = config_strs[0];
cache_config.num_shard_bits = ParseUint32(config_strs[1]);
for (uint32_t i = 2; i < config_strs.size(); i++) {
uint64_t capacity = ParseUint64(config_strs[i]);
if (capacity == 0) {
fprintf(stderr, "Invalid cache capacity %s, %s\n",
config_strs[i].c_str(), line.c_str());
exit(1);
}
cache_config.cache_capacities.push_back(capacity);
}
configs.push_back(cache_config);
}
file.close();
return configs;
}
std::set<uint64_t> parse_buckets(const std::string& bucket_str) {
std::set<uint64_t> buckets;
std::stringstream ss(bucket_str);
while (ss.good()) {
std::string bucket;
getline(ss, bucket, ',');
buckets.insert(ParseUint64(bucket));
}
buckets.insert(port::kMaxUint64);
return buckets;
}
int block_cache_trace_analyzer_tool(int argc, char** argv) {
ParseCommandLineFlags(&argc, &argv, true);
if (FLAGS_block_cache_trace_path.empty()) {
fprintf(stderr, "block cache trace path is empty\n");
exit(1);
}
uint64_t warmup_seconds =
FLAGS_cache_sim_warmup_seconds > 0 ? FLAGS_cache_sim_warmup_seconds : 0;
uint32_t downsample_ratio = FLAGS_block_cache_trace_downsample_ratio > 0
? FLAGS_block_cache_trace_downsample_ratio
: 0;
std::vector<CacheConfiguration> cache_configs =
parse_cache_config_file(FLAGS_block_cache_sim_config_path);
std::unique_ptr<BlockCacheTraceSimulator> cache_simulator;
if (!cache_configs.empty()) {
cache_simulator.reset(new BlockCacheTraceSimulator(
warmup_seconds, downsample_ratio, cache_configs));
}
BlockCacheTraceAnalyzer analyzer(FLAGS_block_cache_trace_path,
FLAGS_block_cache_analysis_result_dir,
std::move(cache_simulator));
Status s = analyzer.Analyze();
if (!s.IsIncomplete()) {
// Read all traces.
fprintf(stderr, "Cannot process the trace %s\n", s.ToString().c_str());
exit(1);
}
analyzer.PrintStatsSummary();
if (FLAGS_print_access_count_stats) {
print_break_lines(/*num_break_lines=*/3);
analyzer.PrintAccessCountStats();
}
if (FLAGS_print_block_size_stats) {
print_break_lines(/*num_break_lines=*/3);
analyzer.PrintBlockSizeStats();
}
if (FLAGS_print_data_block_access_count_stats) {
print_break_lines(/*num_break_lines=*/3);
analyzer.PrintDataBlockAccessStats();
}
print_break_lines(/*num_break_lines=*/3);
analyzer.WriteMissRatioCurves();
if (!FLAGS_timeline_labels.empty()) {
std::stringstream ss(FLAGS_timeline_labels);
while (ss.good()) {
std::string label;
getline(ss, label, ',');
analyzer.WriteAccessTimeline(label);
}
}
if (!FLAGS_reuse_distance_labels.empty() &&
!FLAGS_reuse_distance_buckets.empty()) {
std::set<uint64_t> buckets = parse_buckets(FLAGS_reuse_distance_buckets);
std::stringstream ss(FLAGS_reuse_distance_labels);
while (ss.good()) {
std::string label;
getline(ss, label, ',');
analyzer.WriteReuseDistance(label, buckets);
}
}
if (!FLAGS_reuse_interval_labels.empty() &&
!FLAGS_reuse_interval_buckets.empty()) {
std::set<uint64_t> buckets = parse_buckets(FLAGS_reuse_interval_buckets);
std::stringstream ss(FLAGS_reuse_interval_labels);
while (ss.good()) {
std::string label;
getline(ss, label, ',');
analyzer.WriteReuseInterval(label, buckets);
}
}
return 0;
}
} // namespace rocksdb
#endif // GFLAGS
#endif // ROCKSDB_LITE