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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
120 lines
3.6 KiB
C++
120 lines
3.6 KiB
C++
// Copyright (c) 2011-present, 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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#pragma once
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#include "monitoring/statistics.h"
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#include "rocksdb/system_clock.h"
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namespace ROCKSDB_NAMESPACE {
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// Auto-scoped.
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// Records the measure time into the corresponding histogram if statistics
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// is not nullptr. It is also saved into *elapsed if the pointer is not nullptr
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// and overwrite is true, it will be added to *elapsed if overwrite is false.
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class StopWatch {
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public:
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StopWatch(const std::shared_ptr<SystemClock>& clock, Statistics* statistics,
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const uint32_t hist_type, uint64_t* elapsed = nullptr,
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bool overwrite = true, bool delay_enabled = false)
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: clock_(clock),
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statistics_(statistics),
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hist_type_(hist_type),
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elapsed_(elapsed),
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overwrite_(overwrite),
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stats_enabled_(statistics &&
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statistics->get_stats_level() >=
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StatsLevel::kExceptTimers &&
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statistics->HistEnabledForType(hist_type)),
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delay_enabled_(delay_enabled),
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total_delay_(0),
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delay_start_time_(0),
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start_time_((stats_enabled_ || elapsed != nullptr) ? clock->NowMicros()
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: 0) {}
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~StopWatch() {
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if (elapsed_) {
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if (overwrite_) {
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*elapsed_ = clock_->NowMicros() - start_time_;
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} else {
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*elapsed_ += clock_->NowMicros() - start_time_;
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}
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}
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if (elapsed_ && delay_enabled_) {
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*elapsed_ -= total_delay_;
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}
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if (stats_enabled_) {
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statistics_->reportTimeToHistogram(
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hist_type_, (elapsed_ != nullptr)
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? *elapsed_
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: (clock_->NowMicros() - start_time_));
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}
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}
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void DelayStart() {
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// if delay_start_time_ is not 0, it means we are already tracking delay,
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// so delay_start_time_ should not be overwritten
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if (elapsed_ && delay_enabled_ && delay_start_time_ == 0) {
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delay_start_time_ = clock_->NowMicros();
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}
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}
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void DelayStop() {
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if (elapsed_ && delay_enabled_ && delay_start_time_ != 0) {
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total_delay_ += clock_->NowMicros() - delay_start_time_;
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}
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// reset to 0 means currently no delay is being tracked, so two consecutive
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// calls to DelayStop will not increase total_delay_
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delay_start_time_ = 0;
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}
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uint64_t GetDelay() const { return delay_enabled_ ? total_delay_ : 0; }
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uint64_t start_time() const { return start_time_; }
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private:
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const std::shared_ptr<SystemClock> clock_;
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Statistics* statistics_;
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const uint32_t hist_type_;
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uint64_t* elapsed_;
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bool overwrite_;
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bool stats_enabled_;
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bool delay_enabled_;
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uint64_t total_delay_;
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uint64_t delay_start_time_;
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const uint64_t start_time_;
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};
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// a nano second precision stopwatch
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class StopWatchNano {
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public:
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explicit StopWatchNano(const std::shared_ptr<SystemClock>& clock,
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bool auto_start = false)
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: clock_(clock), start_(0) {
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if (auto_start) {
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Start();
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}
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}
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void Start() { start_ = clock_->NowNanos(); }
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uint64_t ElapsedNanos(bool reset = false) {
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auto now = clock_->NowNanos();
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auto elapsed = now - start_;
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if (reset) {
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start_ = now;
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}
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return elapsed;
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}
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uint64_t ElapsedNanosSafe(bool reset = false) {
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return (clock_ != nullptr) ? ElapsedNanos(reset) : 0U;
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}
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private:
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const std::shared_ptr<SystemClock> clock_;
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uint64_t start_;
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};
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} // namespace ROCKSDB_NAMESPACE
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