rocksdb/monitoring/histogram_windowing.h
Jay Zhuang 58660bf21a Use mock time for histogram_test (#7799)
Summary:
`histogram_test` uses real sleep, which depends on the test executing speed, it makes the test unstable.
Switching to using a mock time env, it can also increase the test speed (from 10100ms -> 100ms).

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7799

Test Plan:
run test 10 times, all passed. vs. without fix 3 out 10 test failed:
no fix: https://app.circleci.com/pipelines/github/facebook/rocksdb?branch=pull%2F7797
with fix: https://app.circleci.com/pipelines/github/facebook/rocksdb?branch=pull%2F7799

Reviewed By: pdillinger

Differential Revision: D25676948

Pulled By: jay-zhuang

fbshipit-source-id: 64c273fc299c53283138dbb213386e4b45e8bdc2
2021-01-04 13:12:40 -08:00

85 lines
2.9 KiB
C++

// 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"
#include "rocksdb/env.h"
namespace ROCKSDB_NAMESPACE {
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_UpdateEnv(Env* env) { env_ = env; }
#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);
}
Env* env_;
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