Disable spinlocks

[stockfish] / src / thread.h

diff --git a/src/thread.h b/src/thread.h
index 3f902dc17b794a35250f87759e932dd9f0607bd4..0469dc1d70fa180cfe17ca6a38e1c7a733b1ba28 100644 (file)
--- a/src/thread.h
+++ b/src/thread.h
@@ -20,6 +20,7 @@
 #ifndef THREAD_H_INCLUDED
 #define THREAD_H_INCLUDED
 
+#include <atomic>
 #include <bitset>
 #include <condition_variable>
 #include <mutex>
@@ -31,11 +32,26 @@
 #include "pawns.h"
 #include "position.h"
 #include "search.h"
+#include "thread_win32.h"
 
 struct Thread;
 
-const int MAX_THREADS = 128;
-const int MAX_SPLITPOINTS_PER_THREAD = 8;
+const size_t MAX_THREADS = 128;
+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 {
+
+  Mutex m; // WARNING: Diasabled spinlocks to test on fishtest
+
+public:
+  void acquire() { m.lock(); }
+  void release() { m.unlock(); }
+};
+
 
 /// SplitPoint struct stores information shared by the threads searching in
 /// parallel below the same split point. It is populated at splitting time.
@@ -45,7 +61,7 @@ struct SplitPoint {
   // Const data after split point has been setup
   const Position* pos;
   Search::Stack* ss;
-  Thread* masterThread;
+  Thread* master;
   Depth depth;
   Value beta;
   int nodeType;
@@ -56,7 +72,7 @@ struct SplitPoint {
   SplitPoint* parentSplitPoint;
 
   // Shared variable data
-  std::mutex mutex;
+  Spinlock spinlock;
   std::bitset<MAX_THREADS> slavesMask;
   volatile bool allSlavesSearching;
   volatile uint64_t nodes;
@@ -79,8 +95,8 @@ 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;
 };
 
@@ -95,7 +111,7 @@ 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);
@@ -108,7 +124,7 @@ struct Thread : public ThreadBase {
   size_t idx;
   int maxPly;
   SplitPoint* volatile activeSplitPoint;
-  volatile int splitPointsSize;
+  volatile size_t splitPointsSize;
   volatile bool searching;
 };
 
@@ -142,13 +158,13 @@ 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;
-  std::mutex mutex;
-  std::condition_variable sleepCondition;
+  Spinlock spinlock;
+  ConditionVariable sleepCondition;
   TimerThread* timer;
 };