2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2021 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>
34 #include "thread_win32_osx.h"
38 /// Thread class keeps together all the thread-related stuff. We use
39 /// per-thread pawn and material hash tables so that once we get a
40 /// pointer to an entry its life time is unlimited and we don't have
41 /// to care about someone changing the entry under our feet.
46 std::condition_variable cv;
48 bool exit = false, searching = true; // Set before starting std::thread
49 NativeThread stdThread;
52 explicit Thread(size_t);
54 virtual void search();
57 void start_searching();
58 void wait_for_search_finished();
60 Pawns::Table pawnsTable;
61 Material::Table materialTable;
63 uint64_t ttHitAverage;
64 int selDepth, nmpMinPly;
66 std::atomic<uint64_t> nodes, tbHits, TTsaves, bestMoveChanges;
70 Search::RootMoves rootMoves;
71 Depth rootDepth, completedDepth;
72 CounterMoveHistory counterMoves;
73 ButterflyHistory mainHistory;
74 LowPlyHistory lowPlyHistory;
75 CapturePieceToHistory captureHistory;
76 ContinuationHistory continuationHistory[2][2];
82 Cluster::TTCache<Cluster::TTCacheSize> buffer = {};
88 /// MainThread is a derived class specific for main thread
90 struct MainThread : public Thread {
94 void search() override;
97 double previousTimeReduction;
98 Value bestPreviousScore;
101 bool stopOnPonderhit;
102 std::atomic_bool ponder;
106 /// ThreadPool struct handles all the threads-related stuff like init, starting,
107 /// parking and, most importantly, launching a thread. All the access to threads
108 /// is done through this class.
110 struct ThreadPool : public std::vector<Thread*> {
112 void start_thinking(Position&, StateListPtr&, const Search::LimitsType&, bool = false);
116 MainThread* main() const { return static_cast<MainThread*>(front()); }
117 uint64_t nodes_searched() const { return accumulate(&Thread::nodes); }
118 uint64_t tb_hits() const { return accumulate(&Thread::tbHits); }
119 uint64_t TT_saves() const { return accumulate(&Thread::TTsaves); }
120 Thread* get_best_thread() const;
121 void start_searching();
122 void wait_for_search_finished() const;
124 std::atomic_bool stop, increaseDepth;
127 StateListPtr setupStates;
129 uint64_t accumulate(std::atomic<uint64_t> Thread::* member) const {
132 for (Thread* th : *this)
133 sum += (th->*member).load(std::memory_order_relaxed);
138 extern ThreadPool Threads;
140 } // namespace Stockfish
142 #endif // #ifndef THREAD_H_INCLUDED