rocksdb/monitoring/statistics.h
Andrew Kryczka ac39d6bec5 Core-local statistics
Summary:
This diff changes `StatisticsImpl` from a thread-local approach to a core-local one. The goal is to perform faster aggregations, particularly for applications that have many threads. There should be no behavior change.
Closes https://github.com/facebook/rocksdb/pull/2258

Differential Revision: D5016258

Pulled By: ajkr

fbshipit-source-id: 7d4d165b4a91d8110f0409d113d1be91f22d31a9
2017-05-23 10:42:59 -07:00

118 lines
4 KiB
C++

// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
// This source code is also licensed under the GPLv2 license found in the
// COPYING file in the root directory of this source tree.
//
#pragma once
#include "rocksdb/statistics.h"
#include <vector>
#include <atomic>
#include <string>
#include "monitoring/histogram.h"
#include "port/likely.h"
#include "port/port.h"
#include "util/core_local.h"
#include "util/mutexlock.h"
#ifdef __clang__
#define ROCKSDB_FIELD_UNUSED __attribute__((__unused__))
#else
#define ROCKSDB_FIELD_UNUSED
#endif // __clang__
namespace rocksdb {
enum TickersInternal : uint32_t {
INTERNAL_TICKER_ENUM_START = TICKER_ENUM_MAX,
INTERNAL_TICKER_ENUM_MAX
};
enum HistogramsInternal : uint32_t {
INTERNAL_HISTOGRAM_START = HISTOGRAM_ENUM_MAX,
INTERNAL_HISTOGRAM_ENUM_MAX
};
class StatisticsImpl : public Statistics {
public:
StatisticsImpl(std::shared_ptr<Statistics> stats,
bool enable_internal_stats);
virtual ~StatisticsImpl();
virtual uint64_t getTickerCount(uint32_t ticker_type) const override;
virtual void histogramData(uint32_t histogram_type,
HistogramData* const data) const override;
std::string getHistogramString(uint32_t histogram_type) const override;
virtual void setTickerCount(uint32_t ticker_type, uint64_t count) override;
virtual uint64_t getAndResetTickerCount(uint32_t ticker_type) override;
virtual void recordTick(uint32_t ticker_type, uint64_t count) override;
virtual void measureTime(uint32_t histogram_type, uint64_t value) override;
virtual Status Reset() override;
virtual std::string ToString() const override;
virtual bool HistEnabledForType(uint32_t type) const override;
private:
// If non-nullptr, forwards updates to the object pointed to by `stats_`.
std::shared_ptr<Statistics> stats_;
// TODO(ajkr): clean this up since there are no internal stats anymore
bool enable_internal_stats_;
// Synchronizes anything that operates across other cores' local data,
// such that operations like Reset() can be performed atomically.
mutable port::Mutex aggregate_lock_;
// The ticker/histogram data are stored in this structure, which we will store
// per-core. It is cache-aligned, so tickers/histograms belonging to different
// cores can never share the same cache line.
//
// Alignment attributes expand to nothing depending on the platform
struct StatisticsData {
std::atomic_uint_fast64_t tickers_[INTERNAL_TICKER_ENUM_MAX] = {{0}};
HistogramImpl histograms_[INTERNAL_HISTOGRAM_ENUM_MAX];
char
padding[(CACHE_LINE_SIZE -
(INTERNAL_TICKER_ENUM_MAX * sizeof(std::atomic_uint_fast64_t) +
INTERNAL_HISTOGRAM_ENUM_MAX * sizeof(HistogramImpl)) %
CACHE_LINE_SIZE) %
CACHE_LINE_SIZE] ROCKSDB_FIELD_UNUSED;
};
static_assert(sizeof(StatisticsData) % 64 == 0, "Expected 64-byte aligned");
CoreLocalArray<StatisticsData> per_core_stats_;
uint64_t getTickerCountLocked(uint32_t ticker_type) const;
std::unique_ptr<HistogramImpl> getHistogramImplLocked(
uint32_t histogram_type) const;
void setTickerCountLocked(uint32_t ticker_type, uint64_t count);
};
// Utility functions
inline void MeasureTime(Statistics* statistics, uint32_t histogram_type,
uint64_t value) {
if (statistics) {
statistics->measureTime(histogram_type, value);
}
}
inline void RecordTick(Statistics* statistics, uint32_t ticker_type,
uint64_t count = 1) {
if (statistics) {
statistics->recordTick(ticker_type, count);
}
}
inline void SetTickerCount(Statistics* statistics, uint32_t ticker_type,
uint64_t count) {
if (statistics) {
statistics->setTickerCount(ticker_type, count);
}
}
}