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stockfish/src/thread.h

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3.7 KiB
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/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2021 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
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Stockfish is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef THREAD_H_INCLUDED
#define THREAD_H_INCLUDED
#include <atomic>
#include <condition_variable>
#include <mutex>
#include <thread>
#include <vector>
#include "material.h"
#include "movepick.h"
#include "pawns.h"
#include "position.h"
#include "search.h"
#include "thread_win32_osx.h"
namespace Stockfish {
/// Thread class keeps together all the thread-related stuff. We 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 {
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; }
Pawns::Table pawnsTable;
Material::Table materialTable;
size_t pvIdx, pvLast;
RunningAverage doubleExtensionAverage[COLOR_NB];
uint64_t nodesLastExplosive;
uint64_t nodesLastNormal;
std::atomic<uint64_t> nodes, tbHits, bestMoveChanges;
Value bestValue;
int selDepth, nmpMinPly;
Color nmpColor;
ExplosionState state;
Position rootPos;
StateInfo rootState;
Search::RootMoves rootMoves;
Depth rootDepth, completedDepth;
Value rootDelta;
CounterMoveHistory counterMoves;
ButterflyHistory mainHistory;
LowPlyHistory lowPlyHistory;
CapturePieceToHistory captureHistory;
ContinuationHistory continuationHistory[2][2];
Score trend;
};
/// MainThread is a derived class specific for main thread
struct MainThread : public Thread {
using Thread::Thread;
void search() override;
void check_time();
double previousTimeReduction;
Value bestPreviousScore;
Value iterValue[4];
int callsCnt;
bool stopOnPonderhit;
std::atomic_bool ponder;
};
/// 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 : public std::vector<Thread*> {
void start_thinking(Position&, StateListPtr&, const Search::LimitsType&, bool = false);
void clear();
void set(size_t);
MainThread* main() const { return static_cast<MainThread*>(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;
std::atomic_bool stop, increaseDepth;
private:
StateListPtr setupStates;
uint64_t accumulate(std::atomic<uint64_t> Thread::* member) const {
uint64_t sum = 0;
for (Thread* th : *this)
sum += (th->*member).load(std::memory_order_relaxed);
return sum;
}
};
extern ThreadPool Threads;
} // namespace Stockfish
#endif // #ifndef THREAD_H_INCLUDED