1/*
2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
4 Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
5 Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
6
7 Stockfish is free software: you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation, either version 3 of the License, or
10 (at your option) any later version.
11
12 Stockfish is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>.
19*/
20
21#ifndef THREAD_H_INCLUDED
22#define THREAD_H_INCLUDED
23
24#include <atomic>
25#include <condition_variable>
26#include <mutex>
27#include <thread>
28#include <vector>
29
30#include "material.h"
31#include "movepick.h"
32#include "pawns.h"
33#include "position.h"
34#include "search.h"
35#include "thread_win32_osx.h"
36
37
38/// Thread class keeps together all the thread-related stuff. We use
39/// per-thread pawn and material hash tables so that once we get a
40/// pointer to an entry its life time is unlimited and we don't have
41/// to care about someone changing the entry under our feet.
42
43class Thread {
44
45 Mutex mutex;
46 ConditionVariable cv;
47 size_t idx;
48 bool exit = false, searching = true; // Set before starting std::thread
49 NativeThread stdThread;
50
51public:
52 explicit Thread(size_t);
53 virtual ~Thread();
54 virtual void search();
55 void clear();
56 void idle_loop();
57 void start_searching();
58 void wait_for_search_finished();
59
60 Pawns::Table pawnsTable;
61 Material::Table materialTable;
62 size_t pvIdx, pvLast, shuffleExts;
63 int selDepth, nmpMinPly;
64 Color nmpColor;
65 std::atomic<uint64_t> nodes, tbHits, bestMoveChanges;
66
67 Position rootPos;
68 Search::RootMoves rootMoves;
69 Depth rootDepth, completedDepth;
70 CounterMoveHistory counterMoves;
71 ButterflyHistory mainHistory;
72 CapturePieceToHistory captureHistory;
73 ContinuationHistory continuationHistory;
74 Score contempt;
75};
76
77
78/// MainThread is a derived class specific for main thread
79
80struct MainThread : public Thread {
81
82 using Thread::Thread;
83
84 void search() override;
85 void check_time();
86
87 double previousTimeReduction;
88 Value previousScore;
89 int callsCnt;
90 bool stopOnPonderhit;
91 std::atomic_bool ponder;
92};
93
94
95/// ThreadPool struct handles all the threads-related stuff like init, starting,
96/// parking and, most importantly, launching a thread. All the access to threads
97/// is done through this class.
98
99struct ThreadPool : public std::vector<Thread*> {
100
101 void start_thinking(Position&, StateListPtr&, const Search::LimitsType&, bool = false);
102 void clear();
103 void set(size_t);
104
105 MainThread* main() const { return static_cast<MainThread*>(front()); }
106 uint64_t nodes_searched() const { return accumulate(&Thread::nodes); }
107 uint64_t tb_hits() const { return accumulate(&Thread::tbHits); }
108
109 std::atomic_bool stop;
110
111private:
112 StateListPtr setupStates;
113
114 uint64_t accumulate(std::atomic<uint64_t> Thread::* member) const {
115
116 uint64_t sum = 0;
117 for (Thread* th : *this)
118 sum += (th->*member).load(std::memory_order_relaxed);
119 return sum;
120 }
121};
122
123extern ThreadPool Threads;
124
125#endif // #ifndef THREAD_H_INCLUDED
126