Retire spinlocks

[stockfish] / src / thread.h

diff --git a/src/thread.h b/src/thread.h
index ea645b4547fd878742135fdbaa4f7fd79647c14a..231443dbba0d9f9c521b085ec2837c20587b2973 100644 (file)
--- a/src/thread.h
+++ b/src/thread.h
@@ -32,6 +32,7 @@
 #include "pawns.h"
 #include "position.h"
 #include "search.h"
+#include "thread_win32.h"
 
 struct Thread;
 
@@ -40,22 +41,6 @@ const size_t MAX_SPLITPOINTS_PER_THREAD = 8;
 const size_t MAX_SLAVES_PER_SPLITPOINT = 4;
 
 
-/// Spinlock class wraps low level atomic operations to provide a spin lock
-
-class Spinlock {
-
-  std::atomic_int lock;
-
-public:
-  Spinlock() { lock = 1; } // Init here to workaround a bug with MSVC 2013
-  void acquire() {
-    while (lock.fetch_sub(1, std::memory_order_acquire) != 1)
-        while (lock.load(std::memory_order_relaxed) <= 0) {}
-  }
-  void release() { lock.store(1, std::memory_order_release); }
-};
-
-
 /// SplitPoint struct stores information shared by the threads searching in
 /// parallel below the same split point. It is populated at splitting time.
 
@@ -75,7 +60,7 @@ struct SplitPoint {
   SplitPoint* parentSplitPoint;
 
   // Shared variable data
-  Spinlock spinlock;
+  Mutex mutex;
   std::bitset<MAX_THREADS> slavesMask;
   volatile bool allSlavesSearching;
   volatile uint64_t nodes;
@@ -98,8 +83,8 @@ struct ThreadBase {
   void wait_for(volatile const bool& b);
 
   std::thread nativeThread;
-  std::mutex mutex;
-  std::condition_variable sleepCondition;
+  Mutex mutex;
+  ConditionVariable sleepCondition;
   volatile bool exit = false;
 };
 
@@ -114,7 +99,7 @@ struct Thread : public ThreadBase {
   Thread();
   virtual void idle_loop();
   bool cutoff_occurred() const;
-  bool available_to(const Thread* master) const;
+  bool can_join(const SplitPoint* sp) const;
 
   void split(Position& pos, Search::Stack* ss, Value alpha, Value beta, Value* bestValue, Move* bestMove,
              Depth depth, int moveCount, MovePicker* movePicker, int nodeType, bool cutNode);
@@ -161,13 +146,13 @@ struct ThreadPool : public std::vector<Thread*> {
 
   MainThread* main() { return static_cast<MainThread*>(at(0)); }
   void read_uci_options();
-  Thread* available_slave(const Thread* master) const;
+  Thread* available_slave(const SplitPoint* sp) const;
   void wait_for_think_finished();
   void start_thinking(const Position&, const Search::LimitsType&, Search::StateStackPtr&);
 
   Depth minimumSplitDepth;
-  Spinlock spinlock;
-  std::condition_variable sleepCondition;
+  Mutex mutex;
+  ConditionVariable sleepCondition;
   TimerThread* timer;
 };