/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
- Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2004-2023 The Stockfish developers (see AUTHORS file)
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
#define THREAD_H_INCLUDED
#include <atomic>
-#include <bitset>
#include <condition_variable>
+#include <cstddef>
+#include <cstdint>
#include <mutex>
-#include <thread>
#include <vector>
-#include "material.h"
#include "movepick.h"
-#include "pawns.h"
#include "position.h"
#include "search.h"
-
-struct Thread;
-
-const size_t MAX_THREADS = 128;
-const size_t MAX_SPLITPOINTS_PER_THREAD = 8;
-const size_t MAX_SLAVES_PER_SPLITPOINT = 4;
-
-/// Spinlock class wraps low level atomic operations to provide spin lock functionality
-
-class Spinlock {
-
- std::atomic_flag lock;
-
-public:
- Spinlock() { std::atomic_flag_clear(&lock); }
- void acquire() { while (lock.test_and_set(std::memory_order_acquire)) {} }
- void release() { lock.clear(std::memory_order_release); }
+#include "thread_win32_osx.h"
+#include "types.h"
+
+namespace Stockfish {
+
+// Thread class keeps together all the thread-related stuff.
+class Thread {
+
+ std::mutex mutex;
+ std::condition_variable cv;
+ size_t idx;
+ bool exit = false, searching = true; // Set before starting std::thread
+ NativeThread stdThread;
+
+ public:
+ explicit Thread(size_t);
+ virtual ~Thread();
+ virtual void search();
+ void clear();
+ void idle_loop();
+ void start_searching();
+ void wait_for_search_finished();
+ size_t id() const { return idx; }
+
+ size_t pvIdx, pvLast;
+ std::atomic<uint64_t> nodes, tbHits, bestMoveChanges;
+ int selDepth, nmpMinPly;
+ Value bestValue, optimism[COLOR_NB];
+
+ Position rootPos;
+ StateInfo rootState;
+ Search::RootMoves rootMoves;
+ Depth rootDepth, completedDepth;
+ Value rootDelta;
+ Value rootSimpleEval;
+ CounterMoveHistory counterMoves;
+ ButterflyHistory mainHistory;
+ CapturePieceToHistory captureHistory;
+ ContinuationHistory continuationHistory[2][2];
+ PawnHistory pawnHistory;
};
-/// SplitPoint struct stores information shared by the threads searching in
-/// parallel below the same split point. It is populated at splitting time.
-
-struct SplitPoint {
-
- // Const data after split point has been setup
- const Position* pos;
- Search::Stack* ss;
- Thread* master;
- Depth depth;
- Value beta;
- int nodeType;
- bool cutNode;
-
- // Const pointers to shared data
- MovePicker* movePicker;
- SplitPoint* parentSplitPoint;
-
- // Shared variable data
- Spinlock spinlock;
- std::bitset<MAX_THREADS> slavesMask;
- volatile bool allSlavesSearching;
- volatile uint64_t nodes;
- volatile Value alpha;
- volatile Value bestValue;
- volatile Move bestMove;
- volatile int moveCount;
- volatile bool cutoff;
-};
-
-
-/// ThreadBase struct is the base of the hierarchy from where we derive all the
-/// specialized thread classes.
+// MainThread is a derived class specific for main thread
+struct MainThread: public Thread {
-struct ThreadBase {
+ using Thread::Thread;
- virtual ~ThreadBase() = default;
- virtual void idle_loop() = 0;
- void notify_one();
- void wait_for(volatile const bool& b);
+ void search() override;
+ void check_time();
- std::thread nativeThread;
- std::mutex mutex;
- std::condition_variable sleepCondition;
- volatile bool exit = false;
+ double previousTimeReduction;
+ Value bestPreviousScore;
+ Value bestPreviousAverageScore;
+ Value iterValue[4];
+ int callsCnt;
+ bool stopOnPonderhit;
+ std::atomic_bool ponder;
};
-/// 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.
+// ThreadPool struct handles all the threads-related stuff like init, starting,
+// parking and, most importantly, launching a thread. All the access to threads
+// is done through this class.
+struct ThreadPool {
-struct Thread : public ThreadBase {
+ void start_thinking(Position&, StateListPtr&, const Search::LimitsType&, bool = false);
+ void clear();
+ void set(size_t);
- Thread();
- virtual void idle_loop();
- bool cutoff_occurred() const;
- bool available_to(const Thread* master) const;
+ MainThread* main() const { return static_cast<MainThread*>(threads.front()); }
+ uint64_t nodes_searched() const { return accumulate(&Thread::nodes); }
+ uint64_t tb_hits() const { return accumulate(&Thread::tbHits); }
+ Thread* get_best_thread() const;
+ void start_searching();
+ void wait_for_search_finished() const;
- void split(Position& pos, Search::Stack* ss, Value alpha, Value beta, Value* bestValue, Move* bestMove,
- Depth depth, int moveCount, MovePicker* movePicker, int nodeType, bool cutNode);
+ std::atomic_bool stop, increaseDepth;
- SplitPoint splitPoints[MAX_SPLITPOINTS_PER_THREAD];
- Pawns::Table pawnsTable;
- Material::Table materialTable;
- Endgames endgames;
- Position* activePosition;
- size_t idx;
- int maxPly;
- SplitPoint* volatile activeSplitPoint;
- volatile size_t splitPointsSize;
- volatile bool searching;
-};
+ auto cbegin() const noexcept { return threads.cbegin(); }
+ auto begin() noexcept { return threads.begin(); }
+ auto end() noexcept { return threads.end(); }
+ auto cend() const noexcept { return threads.cend(); }
+ auto size() const noexcept { return threads.size(); }
+ auto empty() const noexcept { return threads.empty(); }
+ private:
+ StateListPtr setupStates;
+ std::vector<Thread*> threads;
-/// MainThread and TimerThread are derived classes used to characterize the two
-/// special threads: the main one and the recurring timer.
+ uint64_t accumulate(std::atomic<uint64_t> Thread::*member) const {
-struct MainThread : public Thread {
- virtual void idle_loop();
- volatile bool thinking = true; // Avoid a race with start_thinking()
-};
-
-struct TimerThread : public ThreadBase {
-
- static const int Resolution = 5; // Millisec between two check_time() calls
-
- virtual void idle_loop();
-
- bool run = false;
-};
-
-
-/// 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();
- Thread* available_slave(const Thread* master) const;
- void wait_for_think_finished();
- void start_thinking(const Position&, const Search::LimitsType&, Search::StateStackPtr&);
-
- Depth minimumSplitDepth;
- Spinlock spinlock;
- std::condition_variable sleepCondition;
- TimerThread* timer;
+ uint64_t sum = 0;
+ for (Thread* th : threads)
+ sum += (th->*member).load(std::memory_order_relaxed);
+ return sum;
+ }
};
extern ThreadPool Threads;
-#endif // #ifndef THREAD_H_INCLUDED
+} // namespace Stockfish
+
+#endif // #ifndef THREAD_H_INCLUDED
projects / stockfish / blobdiff