From 068a7cfac6f17be1ac51aab74bb2dbf018c67c6d Mon Sep 17 00:00:00 2001 From: gabi Date: Sat, 29 Nov 2014 17:11:25 +0200 Subject: [PATCH] Start of work on lockfreee async queue --- include/spdlog/details/mpcs_q.h | 168 ++++++++++++++++++++++++++++++++ 1 file changed, 168 insertions(+) create mode 100644 include/spdlog/details/mpcs_q.h diff --git a/include/spdlog/details/mpcs_q.h b/include/spdlog/details/mpcs_q.h new file mode 100644 index 00000000..acc62a75 --- /dev/null +++ b/include/spdlog/details/mpcs_q.h @@ -0,0 +1,168 @@ +#pragma once +/*************************************************************************/ +/* +Modified version of Intrusive MPSC node-based queue + +Original code from +http://www.1024cores.net/home/lock-free-algorithms/queues/intrusive-mpsc-node-based-queue +licensed by Dmitry Vyukov under the terms below: + +Simplified BSD license + +Copyright (c) 2010-2011 Dmitry Vyukov. All rights reserved. +Redistribution and use in source and binary forms, with or without modification, +are permitted provided that the following conditions are met: +1. Redistributions of source code must retain the above copyright notice, this list of +conditions and the following disclaimer. + +2. 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. + +THIS SOFTWARE IS PROVIDED BY DMITRY VYUKOV "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 DMITRY VYUKOV OR CONTRIBUTORS 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. + +The views and conclusions contained in the software and documentation are those of the authors and +should not be interpreted as representing official policies, either expressed or implied, of Dmitry Vyukov. + +/*************************************************************************/ +/* The code in its current form adds the license below: */ +/*************************************************************************/ +/* spdlog - an extremely fast and easy to use c++11 logging library. */ +/* Copyright (c) 2014 Gabi Melman. */ +/* */ +/* Permission is hereby granted, free of charge, to any person obtaining */ +/* a copy of this software and associated documentation files (the */ +/* "Software"), to deal in the Software without restriction, including */ +/* without limitation the rights to use, copy, modify, merge, publish, */ +/* distribute, sublicense, and/or sell copies of the Software, and to */ +/* permit persons to whom the Software is furnished to do so, subject to */ +/* the following conditions: */ +/* */ +/* The above copyright notice and this permission notice shall be */ +/* included in all copies or substantial portions of the Software. */ +/* */ +/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */ +/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */ +/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/ +/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */ +/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */ +/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */ +/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ +/*************************************************************************/ + + +#include +namespace spdlog { +namespace details { +template +class mpsc_q +{ + +public: + mpsc_q(size_t size) :_stub(T()), _head(&_stub), _tail(&_stub) + { + _stub.next = nullptr; + } + + ~mpsc_q() + { + reset(); + } + + void reset() + { + T dummy_val; + while (pop(dummy_val)); + } + + bool push(const T& value) + { + mpscq_node_t* new_node = new mpscq_node_t(value); + push_node(new_node); + return true; + } + + bool pop(T& value) + { + mpscq_node_t* node = pop_node(); + if (node != nullptr) + { + value = node->value; + delete(node); + return true; + } + else + { + return false; + } + } + +private: + struct mpscq_node_t + { + std::atomic next; + T value; + + explicit mpscq_node_t(const T& value) :next(nullptr), value(value) + { + } + }; + + mpscq_node_t _stub; + std::atomic _head; + mpscq_node_t* _tail; + + + + void push_node(mpscq_node_t* n) + { + n->next = nullptr; + mpscq_node_t* prev = _head.exchange(n); + prev->next = n; + } + + mpscq_node_t* pop_node() + { + mpscq_node_t* tail = _tail; + mpscq_node_t* next = tail->next; + if (tail == &_stub) + { + if (nullptr == next) + return nullptr; + _tail = next; + tail = next; + next = next->next; + } + if (next) + { + _tail = next; + return tail; + } + mpscq_node_t* head = _head; + if (tail != head) + return 0; + + push_node(&_stub); + next = tail->next; + if (next) + { + _tail = next; + return tail; + } + return nullptr; + } + + + +}; +} +} \ No newline at end of file