50-moves rule improvement for transposition table

[stockfish] / src / thread_win32_osx.h

diff --git a/src/thread_win32_osx.h b/src/thread_win32_osx.h
index 8890054020459b0d57ca445ed4a17b9ab6c4c66d..0ef5c98132ae395c617f9b6e5dbd9ee1938f9409 100644 (file)
--- a/src/thread_win32_osx.h
+++ b/src/thread_win32_osx.h
@@ -2,7 +2,7 @@
   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) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2020 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -21,63 +21,19 @@
 #ifndef THREAD_WIN32_OSX_H_INCLUDED
 #define THREAD_WIN32_OSX_H_INCLUDED
 
-/// STL thread library used by mingw and gcc when cross compiling for Windows
-/// relies on libwinpthread. Currently libwinpthread implements mutexes directly
-/// on top of Windows semaphores. Semaphores, being kernel objects, require kernel
-/// mode transition in order to lock or unlock, which is very slow compared to
-/// interlocked operations (about 30% slower on bench test). To work around this
-/// issue, we define our wrappers to the low level Win32 calls. We use critical
-/// sections to support Windows XP and older versions. Unfortunately, cond_wait()
-/// is racy between unlock() and WaitForSingleObject() but they have the same
-/// speed performance as the SRW locks.
-
-#include <condition_variable>
-#include <mutex>
 #include <thread>
 
-#if defined(_WIN32) && !defined(_MSC_VER)
-
-#ifndef NOMINMAX
-#  define NOMINMAX // Disable macros min() and max()
-#endif
-
-#define WIN32_LEAN_AND_MEAN
-#include <windows.h>
-#undef WIN32_LEAN_AND_MEAN
-#undef NOMINMAX
-
-/// Mutex and ConditionVariable struct are wrappers of the low level locking
-/// machinery and are modeled after the corresponding C++11 classes.
-
-struct Mutex {
-  Mutex() { InitializeCriticalSection(&cs); }
- ~Mutex() { DeleteCriticalSection(&cs); }
-  void lock() { EnterCriticalSection(&cs); }
-  void unlock() { LeaveCriticalSection(&cs); }
-
-private:
-  CRITICAL_SECTION cs;
-};
-
-typedef std::condition_variable_any ConditionVariable;
-
-#else // Default case: use STL classes
-
-typedef std::mutex Mutex;
-typedef std::condition_variable ConditionVariable;
-
-#endif
-
 /// On OSX threads other than the main thread are created with a reduced stack
-/// size of 512KB by default, this is dangerously low for deep searches, so
-/// adjust it to TH_STACK_SIZE. The implementation calls pthread_create() with
-/// proper stack size parameter.
+/// size of 512KB by default, this is too low for deep searches, which require
+/// somewhat more than 1MB stack, so adjust it to TH_STACK_SIZE.
+/// The implementation calls pthread_create() with the stack size parameter
+/// equal to the linux 8MB default, on platforms that support it.
 
-#if defined(__APPLE__)
+#if defined(__APPLE__) || defined(__MINGW32__) || defined(__MINGW64__)
 
 #include <pthread.h>
 
-static const size_t TH_STACK_SIZE = 2 * 1024 * 1024;
+static const size_t TH_STACK_SIZE = 8 * 1024 * 1024;
 
 template <class T, class P = std::pair<T*, void(T::*)()>>
 void* start_routine(void* ptr)