Libosmium  2.15.2
Fast and flexible C++ library for working with OpenStreetMap data
pool.hpp
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1 #ifndef OSMIUM_THREAD_POOL_HPP
2 #define OSMIUM_THREAD_POOL_HPP
3 
4 /*
5 
6 This file is part of Osmium (https://osmcode.org/libosmium).
7 
8 Copyright 2013-2019 Jochen Topf <jochen@topf.org> and others (see README).
9 
10 Boost Software License - Version 1.0 - August 17th, 2003
11 
12 Permission is hereby granted, free of charge, to any person or organization
13 obtaining a copy of the software and accompanying documentation covered by
14 this license (the "Software") to use, reproduce, display, distribute,
15 execute, and transmit the Software, and to prepare derivative works of the
16 Software, and to permit third-parties to whom the Software is furnished to
17 do so, all subject to the following:
18 
19 The copyright notices in the Software and this entire statement, including
20 the above license grant, this restriction and the following disclaimer,
21 must be included in all copies of the Software, in whole or in part, and
22 all derivative works of the Software, unless such copies or derivative
23 works are solely in the form of machine-executable object code generated by
24 a source language processor.
25 
26 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
27 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
28 FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
29 SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
30 FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
31 ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
32 DEALINGS IN THE SOFTWARE.
33 
34 */
35 
37 #include <osmium/thread/queue.hpp>
38 #include <osmium/thread/util.hpp>
39 #include <osmium/util/config.hpp>
40 
41 #include <cstddef>
42 #include <future>
43 #include <thread>
44 #include <type_traits>
45 #include <utility>
46 #include <vector>
47 
48 namespace osmium {
49 
53  namespace thread {
54 
55  namespace detail {
56 
57  // Maximum number of allowed pool threads (just to keep the user
58  // from setting something silly).
59  enum {
60  max_pool_threads = 32
61  };
62 
63  inline int get_pool_size(int num_threads, int user_setting, unsigned hardware_concurrency) {
64  if (num_threads == 0) {
65  num_threads = user_setting ? user_setting : -2;
66  }
67 
68  if (num_threads < 0) {
69  num_threads += int(hardware_concurrency);
70  }
71 
72  if (num_threads < 1) {
73  num_threads = 1;
74  } else if (num_threads > max_pool_threads) {
75  num_threads = max_pool_threads;
76  }
77 
78  return num_threads;
79  }
80 
81  inline std::size_t get_work_queue_size() noexcept {
82  return osmium::config::get_max_queue_size("WORK", 10);
83  }
84 
85  } // namespace detail
86 
90  class Pool {
91 
96  class thread_joiner {
97 
98  std::vector<std::thread>& m_threads;
99 
100  public:
101 
102  explicit thread_joiner(std::vector<std::thread>& threads) :
103  m_threads(threads) {
104  }
105 
106  thread_joiner(const thread_joiner&) = delete;
107  thread_joiner& operator=(const thread_joiner&) = delete;
108 
109  thread_joiner(thread_joiner&&) = delete;
111 
113  for (auto& thread : m_threads) {
114  if (thread.joinable()) {
115  thread.join();
116  }
117  }
118  }
119 
120  }; // class thread_joiner
121 
123  std::vector<std::thread> m_threads{};
126 
127  void worker_thread() {
128  osmium::thread::set_thread_name("_osmium_worker");
129  while (true) {
130  function_wrapper task;
131  m_work_queue.wait_and_pop(task);
132  if (task && task()) {
133  // The called tasks returns true only when the
134  // worker thread should shut down.
135  return;
136  }
137  }
138  }
139 
140  public:
141 
142  enum {
144  };
145 
146  enum {
148  };
149 
165  explicit Pool(int num_threads = default_num_threads, std::size_t max_queue_size = default_queue_size) :
166  m_work_queue(max_queue_size > 0 ? max_queue_size : detail::get_work_queue_size(), "work"),
168  m_num_threads(detail::get_pool_size(num_threads, osmium::config::get_pool_threads(), std::thread::hardware_concurrency())) {
169 
170  try {
171  for (int i = 0; i < m_num_threads; ++i) {
172  m_threads.emplace_back(&Pool::worker_thread, this);
173  }
174  } catch (...) {
176  throw;
177  }
178  }
179 
180  static Pool& default_instance() {
181  static Pool pool{};
182  return pool;
183  }
184 
186  for (int i = 0; i < m_num_threads; ++i) {
187  // The special function wrapper makes a worker shut down.
189  }
190  }
191 
192  Pool(const Pool&) = delete;
193  Pool& operator=(const Pool&) = delete;
194 
195  Pool(Pool&&) = delete;
196  Pool& operator=(Pool&&) = delete;
197 
198  ~Pool() {
200  }
201 
202  int num_threads() const noexcept {
203  return m_num_threads;
204  }
205 
206  std::size_t queue_size() const {
207  return m_work_queue.size();
208  }
209 
210  bool queue_empty() const {
211  return m_work_queue.empty();
212  }
213 
214  template <typename TFunction>
215  std::future<typename std::result_of<TFunction()>::type> submit(TFunction&& func) {
216  using result_type = typename std::result_of<TFunction()>::type;
217 
218  std::packaged_task<result_type()> task{std::forward<TFunction>(func)};
219  std::future<result_type> future_result{task.get_future()};
220  m_work_queue.push(std::move(task));
221 
222  return future_result;
223  }
224 
225  }; // class Pool
226 
227  } // namespace thread
228 
229 } // namespace osmium
230 
231 #endif // OSMIUM_THREAD_POOL_HPP
type
Definition: entity_bits.hpp:63
Pool & operator=(const Pool &)=delete
static Pool & default_instance()
Definition: pool.hpp:180
Definition: queue.hpp:57
bool queue_empty() const
Definition: pool.hpp:210
void set_thread_name(const char *name) noexcept
Definition: util.hpp:76
~Pool()
Definition: pool.hpp:198
Definition: location.hpp:550
std::size_t queue_size() const
Definition: pool.hpp:206
std::vector< std::thread > & m_threads
Definition: pool.hpp:98
std::future< typename std::result_of< TFunction()>::type > submit(TFunction &&func)
Definition: pool.hpp:215
void worker_thread()
Definition: pool.hpp:127
int get_pool_threads() noexcept
Definition: config.hpp:62
int num_threads() const noexcept
Definition: pool.hpp:202
Namespace for everything in the Osmium library.
Definition: assembler.hpp:53
Definition: attr.hpp:333
Definition: function_wrapper.hpp:48
std::vector< std::thread > m_threads
Definition: pool.hpp:123
Definition: pool.hpp:90
osmium::thread::Queue< function_wrapper > m_work_queue
Definition: pool.hpp:122
thread_joiner(std::vector< std::thread > &threads)
Definition: pool.hpp:102
int m_num_threads
Definition: pool.hpp:125
std::size_t get_max_queue_size(const char *queue_name, const std::size_t default_value) noexcept
Definition: config.hpp:83
~thread_joiner()
Definition: pool.hpp:112
thread_joiner & operator=(const thread_joiner &)=delete
void shutdown_all_workers()
Definition: pool.hpp:185
thread_joiner m_joiner
Definition: pool.hpp:124
Pool(int num_threads=default_num_threads, std::size_t max_queue_size=default_queue_size)
Definition: pool.hpp:165