rocksdb/util/statistics.h
Lei Jin ad0c3747cb cache SuperVersion in thread local storage to avoid mutex lock
Summary: as title

Test Plan:
asan_check
will post results later

Reviewers: haobo, igor, dhruba, sdong

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16257
2014-02-27 11:38:55 -08:00

67 lines
2 KiB
C++

// Copyright (c) 2013, 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.
//
#pragma once
#include "rocksdb/statistics.h"
#include "util/histogram.h"
#include "util/mutexlock.h"
#include "port/likely.h"
#include <vector>
#include <atomic>
namespace rocksdb {
class StatisticsImpl : public Statistics {
public:
StatisticsImpl();
virtual ~StatisticsImpl();
virtual long getTickerCount(Tickers tickerType);
virtual void setTickerCount(Tickers tickerType, uint64_t count);
virtual void recordTick(Tickers tickerType, uint64_t count);
virtual void measureTime(Histograms histogramType, uint64_t value);
virtual void histogramData(Histograms histogramType,
HistogramData* const data);
private:
struct Ticker {
Ticker() : value(uint_fast64_t()) {}
std::atomic_uint_fast64_t value;
// Pad the structure to make it size of 64 bytes. A plain array of
// std::atomic_uint_fast64_t results in huge performance degradataion
// due to false sharing.
char padding[64 - sizeof(std::atomic_uint_fast64_t)];
};
Ticker tickers_[TICKER_ENUM_MAX] __attribute__((aligned(64)));
HistogramImpl histograms_[HISTOGRAM_ENUM_MAX] __attribute__((aligned(64)));
};
// Utility functions
inline void MeasureTime(Statistics* statistics, Histograms histogramType,
uint64_t value) {
if (statistics) {
statistics->measureTime(histogramType, value);
}
}
inline void RecordTick(Statistics* statistics, Tickers ticker,
uint64_t count = 1) {
if (statistics) {
statistics->recordTick(ticker, count);
}
}
inline void SetTickerCount(Statistics* statistics, Tickers ticker,
uint64_t count) {
if (statistics) {
statistics->setTickerCount(ticker, count);
}
}
}