/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2009 Marco Costalba
+ Copyright (C) 2008-2015 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)
+#ifndef THREAD_H_INCLUDED
#define THREAD_H_INCLUDED
+#include <atomic>
+#include <bitset>
+#include <condition_variable>
+#include <mutex>
+#include <thread>
+#include <vector>
-////
-//// Includes
-////
-
-#include <cstring>
-
-#include "lock.h"
+#include "material.h"
#include "movepick.h"
+#include "pawns.h"
#include "position.h"
#include "search.h"
+#include "thread_win32.h"
+
+struct Thread;
+
+const size_t MAX_THREADS = 128;
+
+
+/// ThreadBase struct is the base of the hierarchy from where we derive all the
+/// specialized thread classes.
+
+struct ThreadBase : public std::thread {
+
+ virtual ~ThreadBase() = default;
+ virtual void idle_loop() = 0;
+ void notify_one();
+ void wait(volatile const bool& b);
+ void wait_while(volatile const bool& b);
+
+ Mutex mutex;
+ ConditionVariable sleepCondition;
+ volatile bool exit = false;
+};
-////
-//// Constants and variables
-////
+/// 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.
-const int MAX_THREADS = 8;
-const int ACTIVE_SPLIT_POINTS_MAX = 8;
+struct Thread : public ThreadBase {
+ Thread();
+ virtual void idle_loop();
+ void search(bool isMainThread = false);
-////
-//// Types
-////
+ Pawns::Table pawnsTable;
+ Material::Table materialTable;
+ Endgames endgames;
+ size_t idx, PVIdx;
+ int maxPly;
+ volatile bool searching;
-struct SplitPoint {
+ Position rootPos;
+ Search::RootMoveVector rootMoves;
+ Depth rootDepth;
+ Search::Stack stack[MAX_PLY+4];
+ HistoryStats history;
+ MovesStats counterMoves;
+};
- // Const data after splitPoint has been setup
- SplitPoint* parent;
- const Position* pos;
- bool pvNode;
- Depth depth;
- Value beta;
- int ply, master, slaves[MAX_THREADS];
- SearchStack sstack[MAX_THREADS][PLY_MAX_PLUS_2];
- // Const pointers to shared data
- MovePicker* mp;
- SearchStack* parentSstack;
+/// MainThread and TimerThread are derived classes used to characterize the two
+/// special threads: the main one and the recurring timer.
- // Shared data
- Lock lock;
- volatile Value alpha;
- volatile Value bestValue;
- volatile int moves;
- volatile int cpus;
- volatile bool stopRequest;
+struct MainThread : public Thread {
+ virtual void idle_loop();
+ void join();
+ void think();
+ volatile bool thinking = true; // Avoid a race with start_thinking()
};
-// ThreadState type is used to represent thread's current state
+struct TimerThread : public ThreadBase {
+
+ static const int Resolution = 5; // Millisec between two check_time() calls
+
+ virtual void idle_loop();
-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
+ bool run = false;
};
-struct Thread {
- SplitPoint* splitPoint;
- volatile int activeSplitPoints;
- uint64_t nodes;
- uint64_t betaCutOffs[2];
- volatile bool printCurrentLineRequest;
- volatile ThreadState state;
- unsigned char pad[64]; // set some distance among local data for each thread
+
+/// ThreadPool struct handles all the threads related stuff like init, starting,
+/// parking and, most importantly, launching a slave thread at a split point.
+/// All the access to shared thread data is done through this class.
+
+struct ThreadPool : public std::vector<Thread*> {
+
+ void init(); // No c'tor and d'tor, threads rely on globals that should be
+ void exit(); // initialized and are valid during the whole thread lifetime.
+
+ MainThread* main() { return static_cast<MainThread*>(at(0)); }
+ void read_uci_options();
+ void start_thinking(const Position&, const Search::LimitsType&, Search::StateStackPtr&);
+ int64_t nodes_searched();
+ TimerThread* timer;
};
+extern ThreadPool Threads;
-#endif // !defined(THREAD_H_INCLUDED)
+#endif // #ifndef THREAD_H_INCLUDED