2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
4 Copyright (C) 2008-2012 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
78 Position* slavesPositions[MAX_THREADS];
79 volatile uint64_t slavesMask;
80 volatile int64_t nodes;
82 volatile Value bestValue;
83 volatile Move bestMove;
84 volatile int moveCount;
89 /// Thread struct keeps together all the thread related stuff like locks, state
90 /// and especially split points. We also use per-thread pawn and material hash
91 /// tables so that once we get a pointer to an entry its life time is unlimited
92 /// and we don't have to care about someone changing the entry under our feet.
99 virtual void idle_loop();
101 bool cutoff_occurred() const;
102 bool is_available_to(Thread* master) const;
103 void wait_for(volatile const bool& b);
105 SplitPoint splitPoints[MAX_SPLITPOINTS_PER_THREAD];
106 Material::Table materialTable;
108 Pawns::Table pawnsTable;
112 ConditionVariable sleepCondition;
114 SplitPoint* volatile activeSplitPoint;
115 volatile int splitPointsSize;
116 volatile bool searching;
121 /// MainThread and TimerThread are sublassed from Thread to characterize the two
122 /// special threads: the main one and the recurring timer.
124 struct MainThread : public Thread {
125 MainThread() : thinking(true) {} // Avoid a race with start_thinking()
126 virtual void idle_loop();
127 volatile bool thinking;
130 struct TimerThread : public Thread {
131 TimerThread() : msec(0) {}
132 virtual void idle_loop();
137 /// ThreadPool class handles all the threads related stuff like init, starting,
138 /// parking and, the most important, launching a slave thread at a split point.
139 /// All the access to shared thread data is done through this class.
144 void init(); // No c'tor and d'tor, threads rely on globals that should
145 void exit(); // be initialized and valid during the whole thread lifetime.
147 Thread& operator[](size_t id) { return *threads[id]; }
148 size_t size() const { return threads.size(); }
149 MainThread* main_thread() { return static_cast<MainThread*>(threads[0]); }
150 TimerThread* timer_thread() { return timer; }
152 void read_uci_options();
153 bool slave_available(Thread* master) const;
154 void wait_for_think_finished();
155 void start_thinking(const Position&, const Search::LimitsType&,
156 const std::vector<Move>&, Search::StateStackPtr&);
159 Value split(Position& pos, Search::Stack* ss, Value alpha, Value beta, Value bestValue, Move* bestMove,
160 Depth depth, Move threatMove, int moveCount, MovePicker& mp, int nodeType);
163 Depth minimumSplitDepth;
165 ConditionVariable sleepCondition;
168 std::vector<Thread*> threads;
170 size_t maxThreadsPerSplitPoint;
173 extern ThreadPool Threads;
175 #endif // !defined(THREAD_H_INCLUDED)