| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| // Copyright (c) 2011, François Saint-Jacques |
| // All rights reserved. |
| // |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are met: |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above copyright |
| // notice, this list of conditions and the following disclaimer in the |
| // documentation and/or other materials provided with the distribution. |
| // * Neither the name of the disruptor-- nor the |
| // names of its contributors may be used to endorse or promote products |
| // derived from this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
| // AND |
| // ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
| // WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| // DISCLAIMED. IN NO EVENT SHALL FRANÇOIS SAINT-JACQUES BE LIABLE FOR ANY |
| // DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
| // (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| // LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
| // ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| #ifndef DISRUPTOR_WAITSTRATEGY_H_ // NOLINT |
| #define DISRUPTOR_WAITSTRATEGY_H_ // NOLINT |
| |
| #include <boost/chrono.hpp> |
| #include <boost/date_time/posix_time/posix_time.hpp> |
| #include <boost/thread.hpp> |
| #include <vector> |
| |
| #include "exceptions.h" |
| #include "interface.h" |
| #include "sequence.h" |
| |
| namespace rocketmq { |
| |
| // Strategy options which are available to those waiting on a |
| // {@link RingBuffer} |
| enum WaitStrategyOption { |
| // This strategy uses a condition variable inside a lock to block the |
| // event procesor which saves CPU resource at the expense of lock |
| // contention. |
| kBlockingStrategy, |
| // This strategy uses a progressive back off strategy by first spinning, |
| // then yielding, then sleeping for 1ms period. This is a good strategy |
| // for burst traffic then quiet periods when latency is not critical. |
| kSleepingStrategy, |
| // This strategy calls Thread.yield() in a loop as a waiting strategy |
| // which reduces contention at the expense of CPU resource. |
| kYieldingStrategy, |
| // This strategy call spins in a loop as a waiting strategy which is |
| // lowest and most consistent latency but ties up a CPU. |
| kBusySpinStrategy |
| }; |
| |
| // Blocking strategy that uses a lock and condition variable for |
| // {@link Consumer}s waiting on a barrier. |
| // This strategy should be used when performance and low-latency are not as |
| // important as CPU resource. |
| class BlockingStrategy : public WaitStrategyInterface { |
| public: |
| BlockingStrategy() {} |
| |
| virtual int64_t WaitFor(const std::vector<Sequence*>& dependents, |
| const Sequence& cursor, |
| const SequenceBarrierInterface& barrier, |
| const int64_t& sequence) { |
| int64_t available_sequence = 0; |
| // We need to wait. |
| if ((available_sequence = cursor.sequence()) < sequence) { |
| // acquire lock |
| boost::unique_lock<boost::recursive_mutex> ulock(mutex_); |
| while ((available_sequence = cursor.sequence()) < sequence) { |
| barrier.CheckAlert(); |
| consumer_notify_condition_.wait(ulock); |
| } |
| } // unlock happens here, on ulock destruction. |
| |
| if (0 != dependents.size()) { |
| while ((available_sequence = GetMinimumSequence(dependents)) < sequence) { |
| barrier.CheckAlert(); |
| } |
| } |
| |
| return available_sequence; |
| } |
| |
| virtual int64_t WaitFor(const std::vector<Sequence*>& dependents, |
| const Sequence& cursor, |
| const SequenceBarrierInterface& barrier, |
| const int64_t& sequence, |
| const int64_t& timeout_micros) { |
| int64_t available_sequence = 0; |
| // We have to wait |
| if ((available_sequence = cursor.sequence()) < sequence) { |
| boost::unique_lock<boost::recursive_mutex> ulock(mutex_); |
| while ((available_sequence = cursor.sequence()) < sequence) { |
| barrier.CheckAlert(); |
| if (boost::cv_status::timeout == |
| consumer_notify_condition_.wait_for( |
| ulock, boost::chrono::microseconds(timeout_micros))) |
| break; |
| } |
| } // unlock happens here, on ulock destruction |
| |
| if (0 != dependents.size()) { |
| while ((available_sequence = GetMinimumSequence(dependents)) < sequence) { |
| barrier.CheckAlert(); |
| } |
| } |
| |
| return available_sequence; |
| } |
| |
| virtual void SignalAllWhenBlocking() { |
| boost::unique_lock<boost::recursive_mutex> ulock(mutex_); |
| consumer_notify_condition_.notify_all(); |
| } |
| |
| private: |
| boost::recursive_mutex mutex_; |
| boost::condition_variable_any consumer_notify_condition_; |
| }; |
| |
| // Sleeping strategy |
| class SleepingStrategy : public WaitStrategyInterface { |
| public: |
| SleepingStrategy() {} |
| |
| virtual int64_t WaitFor(const std::vector<Sequence*>& dependents, |
| const Sequence& cursor, |
| const SequenceBarrierInterface& barrier, |
| const int64_t& sequence) { |
| int64_t available_sequence = 0; |
| int counter = kRetries; |
| |
| if (0 == dependents.size()) { |
| while ((available_sequence = cursor.sequence()) < sequence) { |
| counter = ApplyWaitMethod(barrier, counter); |
| } |
| } else { |
| while ((available_sequence = GetMinimumSequence(dependents)) < sequence) { |
| counter = ApplyWaitMethod(barrier, counter); |
| } |
| } |
| |
| return available_sequence; |
| } |
| |
| virtual int64_t WaitFor(const std::vector<Sequence*>& dependents, |
| const Sequence& cursor, |
| const SequenceBarrierInterface& barrier, |
| const int64_t& sequence, |
| const int64_t& timeout_micros) { |
| // timing |
| boost::posix_time::ptime current_date_microseconds = |
| boost::posix_time::microsec_clock::local_time(); |
| int64_t start_micro = |
| current_date_microseconds.time_of_day().total_milliseconds(); |
| |
| int64_t available_sequence = 0; |
| int counter = kRetries; |
| |
| if (0 == dependents.size()) { |
| while ((available_sequence = cursor.sequence()) < sequence) { |
| counter = ApplyWaitMethod(barrier, counter); |
| boost::posix_time::ptime current_date_microseconds = |
| boost::posix_time::microsec_clock::local_time(); |
| int64_t end_micro = |
| current_date_microseconds.time_of_day().total_milliseconds(); |
| if (timeout_micros < (end_micro - start_micro)) break; |
| } |
| } else { |
| while ((available_sequence = GetMinimumSequence(dependents)) < sequence) { |
| counter = ApplyWaitMethod(barrier, counter); |
| boost::posix_time::ptime current_date_microseconds = |
| boost::posix_time::microsec_clock::local_time(); |
| int64_t end_micro = |
| current_date_microseconds.time_of_day().total_milliseconds(); |
| if (timeout_micros < (end_micro - start_micro)) break; |
| } |
| } |
| |
| return available_sequence; |
| } |
| |
| virtual void SignalAllWhenBlocking() {} |
| |
| static const int kRetries = 200; |
| |
| private: |
| int ApplyWaitMethod(const SequenceBarrierInterface& barrier, int counter) { |
| barrier.CheckAlert(); |
| if (counter > 100) { |
| counter--; |
| } else if (counter > 0) { |
| counter--; |
| boost::this_thread::yield(); |
| } else { |
| boost::this_thread::sleep_for(boost::chrono::milliseconds(1)); |
| } |
| |
| return counter; |
| } |
| }; |
| |
| // Yielding strategy that uses a sleep(0) for {@link EventProcessor}s waiting |
| // on a barrier. This strategy is a good compromise between performance and |
| // CPU resource. |
| class YieldingStrategy : public WaitStrategyInterface { |
| public: |
| YieldingStrategy() {} |
| |
| virtual int64_t WaitFor(const std::vector<Sequence*>& dependents, |
| const Sequence& cursor, |
| const SequenceBarrierInterface& barrier, |
| const int64_t& sequence) { |
| int64_t available_sequence = 0; |
| int counter = kSpinTries; |
| |
| if (0 == dependents.size()) { |
| while ((available_sequence = cursor.sequence()) < sequence) { |
| counter = ApplyWaitMethod(barrier, counter); |
| } |
| } else { |
| while ((available_sequence = GetMinimumSequence(dependents)) < sequence) { |
| counter = ApplyWaitMethod(barrier, counter); |
| } |
| } |
| |
| return available_sequence; |
| } |
| |
| virtual int64_t WaitFor(const std::vector<Sequence*>& dependents, |
| const Sequence& cursor, |
| const SequenceBarrierInterface& barrier, |
| const int64_t& sequence, |
| const int64_t& timeout_micros) { |
| boost::posix_time::ptime current_date_microseconds = |
| boost::posix_time::microsec_clock::local_time(); |
| int64_t start_micro = |
| current_date_microseconds.time_of_day().total_milliseconds(); |
| |
| int64_t available_sequence = 0; |
| int counter = kSpinTries; |
| |
| if (0 == dependents.size()) { |
| while ((available_sequence = cursor.sequence()) < sequence) { |
| counter = ApplyWaitMethod(barrier, counter); |
| boost::posix_time::ptime current_date_microseconds = |
| boost::posix_time::microsec_clock::local_time(); |
| int64_t end_micro = |
| current_date_microseconds.time_of_day().total_milliseconds(); |
| if (timeout_micros < (end_micro - start_micro)) break; |
| } |
| } else { |
| while ((available_sequence = GetMinimumSequence(dependents)) < sequence) { |
| counter = ApplyWaitMethod(barrier, counter); |
| boost::posix_time::ptime current_date_microseconds = |
| boost::posix_time::microsec_clock::local_time(); |
| int64_t end_micro = |
| current_date_microseconds.time_of_day().total_milliseconds(); |
| if (timeout_micros < (end_micro - start_micro)) break; |
| } |
| } |
| |
| return available_sequence; |
| } |
| |
| virtual void SignalAllWhenBlocking() {} |
| |
| static const int kSpinTries = 100; |
| |
| private: |
| int ApplyWaitMethod(const SequenceBarrierInterface& barrier, int counter) { |
| barrier.CheckAlert(); |
| if (counter == 0) { |
| boost::this_thread::yield(); |
| } else { |
| counter--; |
| } |
| |
| return counter; |
| } |
| }; |
| |
| // Busy Spin strategy that uses a busy spin loop for {@link EventProcessor}s |
| // waiting on a barrier. |
| // This strategy will use CPU resource to avoid syscalls which can introduce |
| // latency jitter. It is best used when threads can be bound to specific |
| // CPU cores. |
| class BusySpinStrategy : public WaitStrategyInterface { |
| public: |
| BusySpinStrategy() {} |
| |
| virtual int64_t WaitFor(const std::vector<Sequence*>& dependents, |
| const Sequence& cursor, |
| const SequenceBarrierInterface& barrier, |
| const int64_t& sequence) { |
| int64_t available_sequence = 0; |
| if (0 == dependents.size()) { |
| while ((available_sequence = cursor.sequence()) < sequence) { |
| barrier.CheckAlert(); |
| } |
| } else { |
| while ((available_sequence = GetMinimumSequence(dependents)) < sequence) { |
| barrier.CheckAlert(); |
| } |
| } |
| |
| return available_sequence; |
| } |
| |
| virtual int64_t WaitFor(const std::vector<Sequence*>& dependents, |
| const Sequence& cursor, |
| const SequenceBarrierInterface& barrier, |
| const int64_t& sequence, |
| const int64_t& timeout_micros) { |
| boost::posix_time::ptime current_date_microseconds = |
| boost::posix_time::microsec_clock::local_time(); |
| int64_t start_micro = |
| current_date_microseconds.time_of_day().total_milliseconds(); |
| int64_t available_sequence = 0; |
| |
| if (0 == dependents.size()) { |
| while ((available_sequence = cursor.sequence()) < sequence) { |
| barrier.CheckAlert(); |
| boost::posix_time::ptime current_date_microseconds = |
| boost::posix_time::microsec_clock::local_time(); |
| int64_t end_micro = |
| current_date_microseconds.time_of_day().total_milliseconds(); |
| if (timeout_micros < (end_micro - start_micro)) break; |
| } |
| } else { |
| while ((available_sequence = GetMinimumSequence(dependents)) < sequence) { |
| barrier.CheckAlert(); |
| boost::posix_time::ptime current_date_microseconds = |
| boost::posix_time::microsec_clock::local_time(); |
| int64_t end_micro = |
| current_date_microseconds.time_of_day().total_milliseconds(); |
| if (timeout_micros < (end_micro - start_micro)) break; |
| } |
| } |
| |
| return available_sequence; |
| } |
| |
| virtual void SignalAllWhenBlocking() {} |
| }; |
| |
| WaitStrategyInterface* CreateWaitStrategy(WaitStrategyOption wait_option) { |
| switch (wait_option) { |
| case kBlockingStrategy: |
| return new BlockingStrategy(); |
| case kSleepingStrategy: |
| return new SleepingStrategy(); |
| case kYieldingStrategy: |
| return new YieldingStrategy(); |
| case kBusySpinStrategy: |
| return new BusySpinStrategy(); |
| default: |
| return NULL; |
| } |
| } |
| |
| }; // namespace rocketmq |
| |
| #endif // DISRUPTOR_WAITSTRATEGY_H_ NOLINT |