Libosmium  2.16.0
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 2013-2021 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;
108 
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 {
147  default_queue_size = 0U
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 
186  static Pool& default_instance() {
187  static Pool pool{};
188  return pool;
189  }
190 
192  for (int i = 0; i < m_num_threads; ++i) {
193  // The special function wrapper makes a worker shut down.
195  }
196  }
197 
198  Pool(const Pool&) = delete;
199  Pool& operator=(const Pool&) = delete;
200 
201  Pool(Pool&&) = delete;
202  Pool& operator=(Pool&&) = delete;
203 
204  ~Pool() {
206  }
207 
208  int num_threads() const noexcept {
209  return m_num_threads;
210  }
211 
212  std::size_t queue_size() const {
213  return m_work_queue.size();
214  }
215 
216  bool queue_empty() const {
217  return m_work_queue.empty();
218  }
219 
220  template <typename TFunction>
221  std::future<typename std::result_of<TFunction()>::type> submit(TFunction&& func) {
222  using result_type = typename std::result_of<TFunction()>::type;
223 
224  std::packaged_task<result_type()> task{std::forward<TFunction>(func)};
225  std::future<result_type> future_result{task.get_future()};
226  m_work_queue.push(std::move(task));
227 
228  return future_result;
229  }
230 
231  }; // class Pool
232 
233  } // namespace thread
234 
235 } // namespace osmium
236 
237 #endif // OSMIUM_THREAD_POOL_HPP
thread_joiner(std::vector< std::thread > &threads)
Definition: pool.hpp:102
thread_joiner & operator=(const thread_joiner &)=delete
thread_joiner(thread_joiner &&)=delete
std::vector< std::thread > & m_threads
Definition: pool.hpp:98
thread_joiner(const thread_joiner &)=delete
thread_joiner & operator=(thread_joiner &&)=delete
~thread_joiner()
Definition: pool.hpp:112
Definition: pool.hpp:90
void shutdown_all_workers()
Definition: pool.hpp:191
static Pool & default_instance()
Definition: pool.hpp:186
std::vector< std::thread > m_threads
Definition: pool.hpp:123
@ default_queue_size
Definition: pool.hpp:147
~Pool()
Definition: pool.hpp:204
Pool(int num_threads=default_num_threads, std::size_t max_queue_size=default_queue_size)
Definition: pool.hpp:165
Pool(Pool &&)=delete
std::size_t queue_size() const
Definition: pool.hpp:212
Pool(const Pool &)=delete
@ default_num_threads
Definition: pool.hpp:143
Pool & operator=(const Pool &)=delete
Pool & operator=(Pool &&)=delete
osmium::thread::Queue< function_wrapper > m_work_queue
Definition: pool.hpp:122
std::future< typename std::result_of< TFunction()>::type > submit(TFunction &&func)
Definition: pool.hpp:221
thread_joiner m_joiner
Definition: pool.hpp:124
bool queue_empty() const
Definition: pool.hpp:216
void worker_thread()
Definition: pool.hpp:127
int m_num_threads
Definition: pool.hpp:125
int num_threads() const noexcept
Definition: pool.hpp:208
Definition: queue.hpp:57
Definition: function_wrapper.hpp:48
Definition: attr.hpp:342
int get_pool_threads() noexcept
Definition: config.hpp:62
std::size_t get_max_queue_size(const char *queue_name, const std::size_t default_value) noexcept
Definition: config.hpp:83
type
Definition: entity_bits.hpp:63
void set_thread_name(const char *name) noexcept
Definition: util.hpp:76
Namespace for everything in the Osmium library.
Definition: assembler.hpp:53
Definition: location.hpp:551