12f1137355
Summary: Introduces and uses a SystemClock class to RocksDB. This class contains the time-related functions of an Env and these functions can be redirected from the Env to the SystemClock. Many of the places that used an Env (Timer, PerfStepTimer, RepeatableThread, RateLimiter, WriteController) for time-related functions have been changed to use SystemClock instead. There are likely more places that can be changed, but this is a start to show what can/should be done. Over time it would be nice to migrate most (if not all) of the uses of the time functions from the Env to the SystemClock. There are several Env classes that implement these functions. Most of these have not been converted yet to SystemClock implementations; that will come in a subsequent PR. It would be good to unify many of the Mock Timer implementations, so that they behave similarly and be tested similarly (some override Sleep, some use a MockSleep, etc). Additionally, this change will allow new methods to be introduced to the SystemClock (like https://github.com/facebook/rocksdb/issues/7101 WaitFor) in a consistent manner across a smaller number of classes. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7858 Reviewed By: pdillinger Differential Revision: D26006406 Pulled By: mrambacher fbshipit-source-id: ed10a8abbdab7ff2e23d69d85bd25b3e7e899e90
87 lines
2.9 KiB
C++
87 lines
2.9 KiB
C++
// Copyright (c) 2013, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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//
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#pragma once
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#include "monitoring/histogram.h"
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namespace ROCKSDB_NAMESPACE {
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class SystemClock;
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class HistogramWindowingImpl : public Histogram
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{
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public:
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HistogramWindowingImpl();
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HistogramWindowingImpl(uint64_t num_windows,
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uint64_t micros_per_window,
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uint64_t min_num_per_window);
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HistogramWindowingImpl(const HistogramWindowingImpl&) = delete;
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HistogramWindowingImpl& operator=(const HistogramWindowingImpl&) = delete;
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~HistogramWindowingImpl();
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virtual void Clear() override;
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virtual bool Empty() const override;
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virtual void Add(uint64_t value) override;
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virtual void Merge(const Histogram& other) override;
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void Merge(const HistogramWindowingImpl& other);
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virtual std::string ToString() const override;
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virtual const char* Name() const override { return "HistogramWindowingImpl"; }
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virtual uint64_t min() const override { return stats_.min(); }
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virtual uint64_t max() const override { return stats_.max(); }
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virtual uint64_t num() const override { return stats_.num(); }
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virtual double Median() const override;
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virtual double Percentile(double p) const override;
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virtual double Average() const override;
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virtual double StandardDeviation() const override;
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virtual void Data(HistogramData* const data) const override;
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#ifndef NDEBUG
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void TEST_UpdateClock(const std::shared_ptr<SystemClock>& clock) {
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clock_ = clock;
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}
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#endif // NDEBUG
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private:
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void TimerTick();
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void SwapHistoryBucket();
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inline uint64_t current_window() const {
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return current_window_.load(std::memory_order_relaxed);
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}
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inline uint64_t last_swap_time() const{
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return last_swap_time_.load(std::memory_order_relaxed);
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}
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std::shared_ptr<SystemClock> clock_;
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std::mutex mutex_;
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// Aggregated stats over windows_stats_, all the computation is done
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// upon aggregated values
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HistogramStat stats_;
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// This is a circular array representing the latest N time-windows.
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// Each entry stores a time-window of data. Expiration is done
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// on window-based.
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std::unique_ptr<HistogramStat[]> window_stats_;
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std::atomic_uint_fast64_t current_window_;
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std::atomic_uint_fast64_t last_swap_time_;
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// Following parameters are configuable
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uint64_t num_windows_ = 5;
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uint64_t micros_per_window_ = 60000000;
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// By default, don't care about the number of values in current window
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// when decide whether to swap windows or not.
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uint64_t min_num_per_window_ = 0;
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};
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} // namespace ROCKSDB_NAMESPACE
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