mirror of
https://github.com/official-stockfish/Stockfish.git
synced 2026-07-22 12:47:08 +00:00
Joost VandeVondeleandJoona Kiiski
3cb0200459
the nodes, tbHits, rootDepth and lastInfoTime variables are read by multiple threads, but not declared atomic, leading to data races as found by -fsanitize=thread. This patch fixes this issue. It is based on top of the CI-threading branch (PR #1129), and should fix the corresponding CI error messages. The patch passed an STC check for no regression: http://tests.stockfishchess.org/tests/view/5925d5590ebc59035df34b9f LLR: 2.96 (-2.94,2.94) [-3.00,1.00] Total: 169597 W: 29938 L: 30066 D: 109593 Whereas rootDepth and lastInfoTime are not performance critical, nodes and tbHits are. Indeed, an earlier version using relaxed atomic updates on the latter two variables failed STC testing (http://tests.stockfishchess.org/tests/view/592001700ebc59035df34924), which can be shown to be due to x86-32 (http://tests.stockfishchess.org/tests/view/592330ac0ebc59035df34a89). Indeed, the latter have no instruction to atomically update a 64bit variable. The proposed solution thus uses a variable in Position that is accessed only by one thread, which is copied every few thousand nodes to the shared variable in Thread. No functional change. Closes #1130 Closes #1129
111 lines
3.1 KiB
C++
111 lines
3.1 KiB
C++
/*
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Stockfish, a UCI chess playing engine derived from Glaurung 2.1
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Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
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Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
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Copyright (C) 2015-2017 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
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Stockfish is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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Stockfish is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef THREAD_H_INCLUDED
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#define THREAD_H_INCLUDED
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#include <atomic>
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#include <condition_variable>
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#include <mutex>
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#include <thread>
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#include <vector>
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#include "material.h"
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#include "movepick.h"
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#include "pawns.h"
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#include "position.h"
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#include "search.h"
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#include "thread_win32.h"
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/// Thread struct keeps together all the thread-related stuff. We also use
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/// per-thread pawn and material hash tables so that once we get a pointer to an
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/// entry its life time is unlimited and we don't have to care about someone
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/// changing the entry under our feet.
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class Thread {
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std::thread nativeThread;
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Mutex mutex;
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ConditionVariable sleepCondition;
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bool exit, searching;
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public:
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Thread();
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virtual ~Thread();
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virtual void search();
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void idle_loop();
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void start_searching(bool resume = false);
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void wait_for_search_finished();
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void wait(std::atomic_bool& condition);
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Pawns::Table pawnsTable;
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Material::Table materialTable;
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Endgames endgames;
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size_t idx, PVIdx;
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int maxPly, callsCnt;
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std::atomic<uint64_t> tbHits;
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std::atomic<uint64_t> nodes;
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Position rootPos;
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Search::RootMoves rootMoves;
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std::atomic<Depth> rootDepth;
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Depth completedDepth;
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std::atomic_bool resetCalls;
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CounterMoveStat counterMoves;
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ButterflyHistory history;
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CounterMoveHistoryStat counterMoveHistory;
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};
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/// MainThread is a derived class with a specific overload for the main thread
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struct MainThread : public Thread {
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virtual void search();
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bool easyMovePlayed, failedLow;
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double bestMoveChanges;
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Value previousScore;
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};
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/// ThreadPool struct handles all the threads-related stuff like init, starting,
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/// parking and, most importantly, launching a thread. All the access to threads
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/// data is done through this class.
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struct ThreadPool : public std::vector<Thread*> {
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void init(); // No constructor and destructor, threads rely on globals that should
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void exit(); // be initialized and valid during the whole thread lifetime.
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MainThread* main() { return static_cast<MainThread*>(at(0)); }
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void start_thinking(Position&, StateListPtr&, const Search::LimitsType&);
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void read_uci_options();
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uint64_t nodes_searched() const;
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uint64_t tb_hits() const;
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private:
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StateListPtr setupStates;
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};
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extern ThreadPool Threads;
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#endif // #ifndef THREAD_H_INCLUDED
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