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ebf3735754
Now that we use spinlocks everywhere and don't put threads to sleep while idle, we can use the slower (but no more in hot path) std::condition_variable_any instead of our homwgrown ConditionVariable struct. Verified fo rno regression at STC with 7 threads: ELO: -0.66 +-2.7 (95%) LOS: 31.8% Total: 20000 W: 3210 L: 3248 D: 13542 No functional change
70 lines
2.4 KiB
C++
70 lines
2.4 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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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_WIN32_H_INCLUDED
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#define THREAD_WIN32_H_INCLUDED
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/// STL thread library used by mingw and gcc when cross compiling for Windows
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/// relies on libwinpthread. Currently libwinpthread implements mutexes directly
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/// on top of Windows semaphores. Semaphores, being kernel objects, require kernel
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/// mode transition in order to lock or unlock, which is very slow compared to
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/// interlocked operations (about 30% slower on bench test). To workaround this
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/// issue, we define our wrappers to the low level Win32 calls. We use critical
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/// sections to support Windows XP and older versions. Unfortunately, cond_wait()
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/// is racy between unlock() and WaitForSingleObject() but they have the same
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/// speed performance of SRW locks.
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#include <condition_variable>
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#include <mutex>
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#if defined(_WIN32) && !defined(_MSC_VER)
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#ifndef NOMINMAX
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# define NOMINMAX // Disable macros min() and max()
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#endif
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#define WIN32_LEAN_AND_MEAN
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#include <windows.h>
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#undef WIN32_LEAN_AND_MEAN
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#undef NOMINMAX
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/// Mutex and ConditionVariable struct are wrappers of the low level locking
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/// machinery and are modeled after the corresponding C++11 classes.
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struct Mutex {
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Mutex() { InitializeCriticalSection(&cs); }
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~Mutex() { DeleteCriticalSection(&cs); }
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void lock() { EnterCriticalSection(&cs); }
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void unlock() { LeaveCriticalSection(&cs); }
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private:
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CRITICAL_SECTION cs;
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};
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typedef std::condition_variable_any ConditionVariable;
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#else // Default case: use STL classes
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typedef std::mutex Mutex;
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typedef std::condition_variable ConditionVariable;
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#endif
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#endif // #ifndef THREAD_WIN32_H_INCLUDED
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