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100 lines
2.3 KiB
C++
100 lines
2.3 KiB
C++
/*! \file
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* \brief Size policies.
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*
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* This file contains size policies for thread_pool. A size
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* policy controls the number of worker threads in the pool.
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*
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* Copyright (c) 2005-2007 Philipp Henkel
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*
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* Use, modification, and distribution are subject to the
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* Boost Software License, Version 1.0. (See accompanying file
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* LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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*
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* http://threadpool.sourceforge.net
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*
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*/
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#ifndef THREADPOOL_SIZE_POLICIES_HPP_INCLUDED
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#define THREADPOOL_SIZE_POLICIES_HPP_INCLUDED
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/// The namespace threadpool contains a thread pool and related utility classes.
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namespace boost { namespace threadpool
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{
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/*! \brief SizePolicyController which provides no functionality.
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*
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* \param Pool The pool's core type.
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*/
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template<typename Pool>
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struct empty_controller
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{
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empty_controller(typename Pool::size_policy_type&, shared_ptr<Pool>) {}
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};
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/*! \brief SizePolicyController which allows resizing.
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*
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* \param Pool The pool's core type.
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*/
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template< typename Pool >
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class resize_controller
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{
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typedef typename Pool::size_policy_type size_policy_type;
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reference_wrapper<size_policy_type> m_policy;
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shared_ptr<Pool> m_pool; //!< to make sure that the pool is alive (the policy pointer is valid) as long as the controller exists
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public:
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resize_controller(size_policy_type& policy, shared_ptr<Pool> pool)
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: m_policy(policy)
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, m_pool(pool)
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{
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}
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bool resize(size_t worker_count)
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{
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return m_policy.get().resize(worker_count);
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}
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};
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/*! \brief SizePolicy which preserves the thread count.
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*
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* \param Pool The pool's core type.
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*/
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template<typename Pool>
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class static_size
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{
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reference_wrapper<Pool volatile> m_pool;
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public:
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static void init(Pool& pool, size_t const worker_count)
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{
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pool.resize(worker_count);
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}
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static_size(Pool volatile & pool)
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: m_pool(pool)
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{}
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bool resize(size_t const worker_count)
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{
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return m_pool.get().resize(worker_count);
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}
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void worker_died_unexpectedly(size_t const new_worker_count)
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{
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m_pool.get().resize(new_worker_count + 1);
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}
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// TODO this functions are not called yet
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void task_scheduled() {}
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void task_finished() {}
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};
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} } // namespace boost::threadpool
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#endif // THREADPOOL_SIZE_POLICIES_HPP_INCLUDED
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