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
78 lines
2.7 KiB
C++
78 lines
2.7 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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#pragma once
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#include <atomic>
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#include <limits>
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#include "rocksdb/system_clock.h"
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namespace ROCKSDB_NAMESPACE {
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// NOTE: SpecialEnv offers most of this functionality, along with hooks
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// for safe DB behavior under a mock time environment, so should be used
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// instead of MockSystemClock for DB tests.
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class MockSystemClock : public SystemClockWrapper {
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public:
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explicit MockSystemClock(const std::shared_ptr<SystemClock>& base)
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: SystemClockWrapper(base) {}
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const char* Name() const override { return "MockSystemClock"; }
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virtual Status GetCurrentTime(int64_t* time_sec) override {
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assert(time_sec != nullptr);
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*time_sec = static_cast<int64_t>(current_time_us_ / kMicrosInSecond);
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return Status::OK();
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}
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virtual uint64_t NowSeconds() { return current_time_us_ / kMicrosInSecond; }
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virtual uint64_t NowMicros() override { return current_time_us_; }
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virtual uint64_t NowNanos() override {
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assert(current_time_us_ <= std::numeric_limits<uint64_t>::max() / 1000);
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return current_time_us_ * 1000;
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}
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uint64_t RealNowMicros() { return target_->NowMicros(); }
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void SetCurrentTime(uint64_t time_sec) {
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assert(time_sec < std::numeric_limits<uint64_t>::max() / kMicrosInSecond);
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assert(time_sec * kMicrosInSecond >= current_time_us_);
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current_time_us_ = time_sec * kMicrosInSecond;
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}
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// It's a fake sleep that just updates the Env current time, which is similar
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// to `NoSleepEnv.SleepForMicroseconds()` and
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// `SpecialEnv.MockSleepForMicroseconds()`.
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// It's also similar to `set_current_time()`, which takes an absolute time in
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// seconds, vs. this one takes the sleep in microseconds.
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// Note: Not thread safe.
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void MockSleepForMicroseconds(int micros) {
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assert(micros >= 0);
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assert(current_time_us_ + static_cast<uint64_t>(micros) >=
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current_time_us_);
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current_time_us_.fetch_add(micros);
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}
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void MockSleepForSeconds(int seconds) {
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assert(seconds >= 0);
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uint64_t micros = static_cast<uint64_t>(seconds) * kMicrosInSecond;
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assert(current_time_us_ + micros >= current_time_us_);
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current_time_us_.fetch_add(micros);
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}
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// TODO: this is a workaround for the different behavior on different platform
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// for timedwait timeout. Ideally timedwait API should be moved to env.
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// details: PR #7101.
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void InstallTimedWaitFixCallback();
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private:
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std::atomic<uint64_t> current_time_us_{0};
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static constexpr uint64_t kMicrosInSecond = 1000U * 1000U;
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};
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} // namespace ROCKSDB_NAMESPACE
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