rocksdb/util/statistics.cc
Andres Noetzli df22e2fb71 Relax memory order for faster tickers
Summary:
The default behavior for atomic operations is sequentially consistent ordering
which is not needed for simple counters (see:
http://en.cppreference.com/w/cpp/atomic/memory_order). Change the memory order
to std::memory_order_relaxed for better performance.

Test Plan: make clean all check

Reviewers: rven, anthony, yhchiang, aekmekji, sdong, MarkCallaghan, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D46953
2015-09-15 10:52:00 -07:00

144 lines
4.2 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.
//
#include "util/statistics.h"
#ifndef __STDC_FORMAT_MACROS
#define __STDC_FORMAT_MACROS
#endif
#include <inttypes.h>
#include "rocksdb/statistics.h"
#include "port/likely.h"
#include <algorithm>
#include <cstdio>
namespace rocksdb {
std::shared_ptr<Statistics> CreateDBStatistics() {
return std::make_shared<StatisticsImpl>(nullptr, false);
}
StatisticsImpl::StatisticsImpl(
std::shared_ptr<Statistics> stats,
bool enable_internal_stats)
: stats_shared_(stats),
stats_(stats.get()),
enable_internal_stats_(enable_internal_stats) {
}
StatisticsImpl::~StatisticsImpl() {}
uint64_t StatisticsImpl::getTickerCount(uint32_t tickerType) const {
assert(
enable_internal_stats_ ?
tickerType < INTERNAL_TICKER_ENUM_MAX :
tickerType < TICKER_ENUM_MAX);
// Return its own ticker version
return tickers_[tickerType].value;
}
void StatisticsImpl::histogramData(uint32_t histogramType,
HistogramData* const data) const {
assert(
enable_internal_stats_ ?
histogramType < INTERNAL_HISTOGRAM_ENUM_MAX :
histogramType < HISTOGRAM_ENUM_MAX);
// Return its own ticker version
histograms_[histogramType].Data(data);
}
std::string StatisticsImpl::getHistogramString(uint32_t histogramType) const {
assert(enable_internal_stats_ ? histogramType < INTERNAL_HISTOGRAM_ENUM_MAX
: histogramType < HISTOGRAM_ENUM_MAX);
return histograms_[histogramType].ToString();
}
void StatisticsImpl::setTickerCount(uint32_t tickerType, uint64_t count) {
assert(
enable_internal_stats_ ?
tickerType < INTERNAL_TICKER_ENUM_MAX :
tickerType < TICKER_ENUM_MAX);
if (tickerType < TICKER_ENUM_MAX || enable_internal_stats_) {
tickers_[tickerType].value.store(count, std::memory_order_relaxed);
}
if (stats_ && tickerType < TICKER_ENUM_MAX) {
stats_->setTickerCount(tickerType, count);
}
}
void StatisticsImpl::recordTick(uint32_t tickerType, uint64_t count) {
assert(
enable_internal_stats_ ?
tickerType < INTERNAL_TICKER_ENUM_MAX :
tickerType < TICKER_ENUM_MAX);
if (tickerType < TICKER_ENUM_MAX || enable_internal_stats_) {
tickers_[tickerType].value.fetch_add(count, std::memory_order_relaxed);
}
if (stats_ && tickerType < TICKER_ENUM_MAX) {
stats_->recordTick(tickerType, count);
}
}
void StatisticsImpl::measureTime(uint32_t histogramType, uint64_t value) {
assert(
enable_internal_stats_ ?
histogramType < INTERNAL_HISTOGRAM_ENUM_MAX :
histogramType < HISTOGRAM_ENUM_MAX);
if (histogramType < HISTOGRAM_ENUM_MAX || enable_internal_stats_) {
histograms_[histogramType].Add(value);
}
if (stats_ && histogramType < HISTOGRAM_ENUM_MAX) {
stats_->measureTime(histogramType, value);
}
}
namespace {
// a buffer size used for temp string buffers
const int kBufferSize = 200;
} // namespace
std::string StatisticsImpl::ToString() const {
std::string res;
res.reserve(20000);
for (const auto& t : TickersNameMap) {
if (t.first < TICKER_ENUM_MAX || enable_internal_stats_) {
char buffer[kBufferSize];
snprintf(buffer, kBufferSize, "%s COUNT : %" PRIu64 "\n",
t.second.c_str(), getTickerCount(t.first));
res.append(buffer);
}
}
for (const auto& h : HistogramsNameMap) {
if (h.first < HISTOGRAM_ENUM_MAX || enable_internal_stats_) {
char buffer[kBufferSize];
HistogramData hData;
histogramData(h.first, &hData);
snprintf(
buffer,
kBufferSize,
"%s statistics Percentiles :=> 50 : %f 95 : %f 99 : %f\n",
h.second.c_str(),
hData.median,
hData.percentile95,
hData.percentile99);
res.append(buffer);
}
}
res.shrink_to_fit();
return res;
}
bool StatisticsImpl::HistEnabledForType(uint32_t type) const {
if (LIKELY(!enable_internal_stats_)) {
return type < HISTOGRAM_ENUM_MAX;
}
return true;
}
} // namespace rocksdb