2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2023 The Stockfish developers (see AUTHORS file)
5 Stockfish is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation, either version 3 of the License, or
8 (at your option) any later version.
10 Stockfish is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>.
19 #ifndef THREAD_H_INCLUDED
20 #define THREAD_H_INCLUDED
23 #include <condition_variable>
32 #include "thread_win32_osx.h"
37 // Thread class keeps together all the thread-related stuff. We use
38 // per-thread pawn and material hash tables so that once we get a
39 // pointer to an entry its lifetime is unlimited and we don't have
40 // to care about someone changing the entry under our feet.
44 std::condition_variable cv;
46 bool exit = false, searching = true; // Set before starting std::thread
47 NativeThread stdThread;
50 explicit Thread(size_t);
52 virtual void search();
55 void start_searching();
56 void wait_for_search_finished();
57 size_t id() const { return idx; }
60 std::atomic<uint64_t> nodes, tbHits, bestMoveChanges;
61 int selDepth, nmpMinPly;
62 Value bestValue, optimism[COLOR_NB];
66 Search::RootMoves rootMoves;
67 Depth rootDepth, completedDepth;
70 CounterMoveHistory counterMoves;
71 ButterflyHistory mainHistory;
72 CapturePieceToHistory captureHistory;
73 ContinuationHistory continuationHistory[2][2];
74 PawnHistory pawnHistory;
78 // MainThread is a derived class specific for main thread
79 struct MainThread: public Thread {
83 void search() override;
86 double previousTimeReduction;
87 Value bestPreviousScore;
88 Value bestPreviousAverageScore;
92 std::atomic_bool ponder;
96 // ThreadPool struct handles all the threads-related stuff like init, starting,
97 // parking and, most importantly, launching a thread. All the access to threads
98 // is done through this class.
101 void start_thinking(Position&, StateListPtr&, const Search::LimitsType&, bool = false);
105 MainThread* main() const { return static_cast<MainThread*>(threads.front()); }
106 uint64_t nodes_searched() const { return accumulate(&Thread::nodes); }
107 uint64_t tb_hits() const { return accumulate(&Thread::tbHits); }
108 Thread* get_best_thread() const;
109 void start_searching();
110 void wait_for_search_finished() const;
112 std::atomic_bool stop, increaseDepth;
114 auto cbegin() const noexcept { return threads.cbegin(); }
115 auto begin() noexcept { return threads.begin(); }
116 auto end() noexcept { return threads.end(); }
117 auto cend() const noexcept { return threads.cend(); }
118 auto size() const noexcept { return threads.size(); }
119 auto empty() const noexcept { return threads.empty(); }
122 StateListPtr setupStates;
123 std::vector<Thread*> threads;
125 uint64_t accumulate(std::atomic<uint64_t> Thread::*member) const {
128 for (Thread* th : threads)
129 sum += (th->*member).load(std::memory_order_relaxed);
134 extern ThreadPool Threads;
136 } // namespace Stockfish
138 #endif // #ifndef THREAD_H_INCLUDED