/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-
#if !defined(THREAD_H_INCLUDED)
#define THREAD_H_INCLUDED
+#include <vector>
-////
-//// Includes
-////
-
-#include <cstring>
-
-#include "lock.h"
+#include "material.h"
#include "movepick.h"
+#include "pawns.h"
#include "position.h"
#include "search.h"
+const int MAX_THREADS = 32;
+const int MAX_SPLITPOINTS_PER_THREAD = 8;
+
+struct Mutex {
+ Mutex() { lock_init(l); }
+ ~Mutex() { lock_destroy(l); }
+
+ void lock() { lock_grab(l); }
+ void unlock() { lock_release(l); }
+
+private:
+ friend struct ConditionVariable;
-////
-//// Constants and variables
-////
+ Lock l;
+};
+
+struct ConditionVariable {
+ ConditionVariable() { cond_init(c); }
+ ~ConditionVariable() { cond_destroy(c); }
-const int MAX_THREADS = 8;
-const int ACTIVE_SPLIT_POINTS_MAX = 8;
+ void wait(Mutex& m) { cond_wait(c, m.l); }
+ void wait_for(Mutex& m, int ms) { timed_wait(c, m.l, ms); }
+ void notify_one() { cond_signal(c); }
+private:
+ WaitCondition c;
+};
-////
-//// Types
-////
+class Thread;
struct SplitPoint {
- // Const data after splitPoint has been setup
- SplitPoint* parent;
+ // Const data after split point has been setup
const Position* pos;
+ const Search::Stack* ss;
Depth depth;
- bool pvNode, mateThreat;
Value beta;
- SearchStack sstack[MAX_THREADS][PLY_MAX_PLUS_2];
+ int nodeType;
+ Thread* master;
+ Move threatMove;
// Const pointers to shared data
MovePicker* mp;
- SearchStack* parentSstack;
+ SplitPoint* parent;
// Shared data
- Lock lock;
+ Mutex mutex;
+ Position* activePositions[MAX_THREADS];
+ volatile uint64_t slavesMask;
+ volatile int64_t nodes;
volatile Value alpha;
volatile Value bestValue;
+ volatile Move bestMove;
volatile int moveCount;
- volatile bool stopRequest;
- volatile int slaves[MAX_THREADS];
+ volatile bool cutoff;
};
-// ThreadState type is used to represent thread's current state
-enum ThreadState
-{
- THREAD_SEARCHING, // thread is performing work
- THREAD_AVAILABLE, // thread is polling for work
- THREAD_SLEEPING, // we are not thinking, so thread is sleeping
- THREAD_BOOKED, // other thread (master) has booked us as a slave
- THREAD_WORKISWAITING, // master has ordered us to start
- THREAD_TERMINATED // we are quitting and thread is terminated
+/// Thread struct keeps together all the thread related stuff like locks, state
+/// and especially split points. We also use per-thread pawn and material hash
+/// tables so that once we get a pointer to an entry its life time is unlimited
+/// and we don't have to care about someone changing the entry under our feet.
+
+class Thread {
+
+ typedef void (Thread::* Fn) (); // Pointer to member function
+
+public:
+ Thread(Fn fn);
+ ~Thread();
+
+ void wake_up();
+ bool cutoff_occurred() const;
+ bool is_available_to(Thread* master) const;
+ void idle_loop();
+ void main_loop();
+ void timer_loop();
+ void wait_for_stop_or_ponderhit();
+
+ SplitPoint splitPoints[MAX_SPLITPOINTS_PER_THREAD];
+ MaterialTable materialTable;
+ PawnTable pawnTable;
+ size_t idx;
+ int maxPly;
+ Mutex mutex;
+ ConditionVariable sleepCondition;
+ NativeHandle handle;
+ Fn start_fn;
+ SplitPoint* volatile curSplitPoint;
+ volatile int splitPointsCnt;
+ volatile bool is_searching;
+ volatile bool do_sleep;
+ volatile bool do_exit;
};
-struct Thread {
- SplitPoint* volatile splitPoint;
- volatile int activeSplitPoints;
- uint64_t nodes;
- uint64_t betaCutOffs[2];
- volatile ThreadState state;
- unsigned char pad[64]; // set some distance among local data for each thread
+
+/// ThreadPool class handles all the threads related stuff like init, starting,
+/// parking and, the most important, launching a slave thread at a split point.
+/// All the access to shared thread data is done through this class.
+
+class ThreadPool {
+
+public:
+ void init(); // No c'tor and d'tor, threads rely on globals that should
+ void exit(); // be initialized and valid during the whole thread lifetime.
+
+ Thread& operator[](size_t id) { return *threads[id]; }
+ bool use_sleeping_threads() const { return useSleepingThreads; }
+ int min_split_depth() const { return minimumSplitDepth; }
+ size_t size() const { return threads.size(); }
+ Thread* main_thread() { return threads[0]; }
+
+ void wake_up() const;
+ void sleep() const;
+ void read_uci_options();
+ bool available_slave_exists(Thread* master) const;
+ void set_timer(int msec);
+ void wait_for_search_finished();
+ void start_searching(const Position&, const Search::LimitsType&,
+ const std::vector<Move>&, Search::StateStackPtr&);
+
+ template <bool Fake>
+ Value split(Position& pos, Search::Stack* ss, Value alpha, Value beta, Value bestValue, Move* bestMove,
+ Depth depth, Move threatMove, int moveCount, MovePicker& mp, int nodeType);
+private:
+ friend class Thread;
+ friend void check_time();
+
+ std::vector<Thread*> threads;
+ Thread* timer;
+ Mutex mutex;
+ ConditionVariable sleepCondition;
+ Depth minimumSplitDepth;
+ int maxThreadsPerSplitPoint;
+ bool useSleepingThreads;
};
+extern ThreadPool Threads;
#endif // !defined(THREAD_H_INCLUDED)
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