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Diffstat (limited to 'src/rocksdb/monitoring/histogram_windowing.h')
-rw-r--r-- | src/rocksdb/monitoring/histogram_windowing.h | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/src/rocksdb/monitoring/histogram_windowing.h b/src/rocksdb/monitoring/histogram_windowing.h new file mode 100644 index 000000000..9a862671f --- /dev/null +++ b/src/rocksdb/monitoring/histogram_windowing.h @@ -0,0 +1,84 @@ +// Copyright (c) 2013, 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). +// +// Copyright (c) 2011 The LevelDB Authors. All rights reserved. +// Use of this source code is governed by a BSD-style license that can be +// found in the LICENSE file. See the AUTHORS file for names of contributors. + +#pragma once + +#include "monitoring/histogram.h" + +namespace ROCKSDB_NAMESPACE { +class SystemClock; + +class HistogramWindowingImpl : public Histogram { + public: + HistogramWindowingImpl(); + HistogramWindowingImpl(uint64_t num_windows, uint64_t micros_per_window, + uint64_t min_num_per_window); + + HistogramWindowingImpl(const HistogramWindowingImpl&) = delete; + HistogramWindowingImpl& operator=(const HistogramWindowingImpl&) = delete; + + ~HistogramWindowingImpl(); + + virtual void Clear() override; + virtual bool Empty() const override; + virtual void Add(uint64_t value) override; + virtual void Merge(const Histogram& other) override; + void Merge(const HistogramWindowingImpl& other); + + virtual std::string ToString() const override; + virtual const char* Name() const override { return "HistogramWindowingImpl"; } + virtual uint64_t min() const override { return stats_.min(); } + virtual uint64_t max() const override { return stats_.max(); } + virtual uint64_t num() const override { return stats_.num(); } + virtual double Median() const override; + virtual double Percentile(double p) const override; + virtual double Average() const override; + virtual double StandardDeviation() const override; + virtual void Data(HistogramData* const data) const override; + +#ifndef NDEBUG + void TEST_UpdateClock(const std::shared_ptr<SystemClock>& clock) { + clock_ = clock; + } +#endif // NDEBUG + + private: + void TimerTick(); + void SwapHistoryBucket(); + inline uint64_t current_window() const { + return current_window_.load(std::memory_order_relaxed); + } + inline uint64_t last_swap_time() const { + return last_swap_time_.load(std::memory_order_relaxed); + } + + std::shared_ptr<SystemClock> clock_; + std::mutex mutex_; + + // Aggregated stats over windows_stats_, all the computation is done + // upon aggregated values + HistogramStat stats_; + + // This is a circular array representing the latest N time-windows. + // Each entry stores a time-window of data. Expiration is done + // on window-based. + std::unique_ptr<HistogramStat[]> window_stats_; + + std::atomic_uint_fast64_t current_window_; + std::atomic_uint_fast64_t last_swap_time_; + + // Following parameters are configuable + uint64_t num_windows_ = 5; + uint64_t micros_per_window_ = 60000000; + // By default, don't care about the number of values in current window + // when decide whether to swap windows or not. + uint64_t min_num_per_window_ = 0; +}; + +} // namespace ROCKSDB_NAMESPACE |