2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
4 Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad
6 Stockfish is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation, either version 3 of the License, or
9 (at your option) any later version.
11 Stockfish is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
20 #if !defined(THREAD_H_INCLUDED)
21 #define THREAD_H_INCLUDED
31 const int MAX_THREADS = 64; // Because SplitPoint::slavesMask is a uint64_t
32 const int MAX_SPLITPOINTS_PER_THREAD = 8;
35 Mutex() { lock_init(l); }
36 ~Mutex() { lock_destroy(l); }
38 void lock() { lock_grab(l); }
39 void unlock() { lock_release(l); }
42 friend struct ConditionVariable;
47 struct ConditionVariable {
48 ConditionVariable() { cond_init(c); }
49 ~ConditionVariable() { cond_destroy(c); }
51 void wait(Mutex& m) { cond_wait(c, m.l); }
52 void wait_for(Mutex& m, int ms) { timed_wait(c, m.l, ms); }
53 void notify_one() { cond_signal(c); }
63 // Const data after split point has been setup
65 const Search::Stack* ss;
72 // Const pointers to shared data
73 MovePicker* movePicker;
74 SplitPoint* parentSplitPoint;
78 volatile uint64_t slavesMask;
79 volatile int64_t nodes;
81 volatile Value bestValue;
82 volatile Move bestMove;
83 volatile int moveCount;
88 /// Thread struct keeps together all the thread related stuff like locks, state
89 /// and especially split points. We also use per-thread pawn and material hash
90 /// tables so that once we get a pointer to an entry its life time is unlimited
91 /// and we don't have to care about someone changing the entry under our feet.
98 virtual void idle_loop();
100 bool cutoff_occurred() const;
101 bool is_available_to(Thread* master) const;
102 void wait_for(volatile const bool& b);
105 void split(Position& pos, Search::Stack* ss, Value alpha, Value beta, Value* bestValue, Move* bestMove,
106 Depth depth, Move threatMove, int moveCount, MovePicker* movePicker, int nodeType);
108 SplitPoint splitPoints[MAX_SPLITPOINTS_PER_THREAD];
109 Material::Table materialTable;
111 Pawns::Table pawnsTable;
112 Position* activePosition;
116 ConditionVariable sleepCondition;
118 SplitPoint* volatile activeSplitPoint;
119 volatile int splitPointsSize;
120 volatile bool searching;
125 /// MainThread and TimerThread are sublassed from Thread to characterize the two
126 /// special threads: the main one and the recurring timer.
128 struct MainThread : public Thread {
129 MainThread() : thinking(true) {} // Avoid a race with start_thinking()
130 virtual void idle_loop();
131 volatile bool thinking;
134 struct TimerThread : public Thread {
135 TimerThread() : msec(0) {}
136 virtual void idle_loop();
141 /// ThreadPool struct handles all the threads related stuff like init, starting,
142 /// parking and, the most important, launching a slave thread at a split point.
143 /// All the access to shared thread data is done through this class.
145 struct ThreadPool : public std::vector<Thread*> {
147 void init(); // No c'tor and d'tor, threads rely on globals that should
148 void exit(); // be initialized and valid during the whole thread lifetime.
150 MainThread* main_thread() { return static_cast<MainThread*>((*this)[0]); }
151 void read_uci_options();
152 Thread* available_slave(Thread* master) const;
153 void wait_for_think_finished();
154 void start_thinking(const Position&, const Search::LimitsType&, const std::vector<Move>&,
155 Search::StateStackPtr&, Search::MovesVectPtr&);
158 Depth minimumSplitDepth;
159 size_t maxThreadsPerSplitPoint;
161 ConditionVariable sleepCondition;
165 extern ThreadPool Threads;
167 #endif // !defined(THREAD_H_INCLUDED)