Use only one ConditionVariable to sync UI

[stockfish] / src / thread.h

diff --git a/src/thread.h b/src/thread.h
index b6809f4e37221dcca2329b62980f07a7e42c5238..215b27c688b2823b11112a56e862645cd7c726d0 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;
 
@@ -39,9 +40,6 @@ 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 {
 
   std::atomic_int lock;
@@ -49,8 +47,9 @@ class Spinlock {
 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) {}
+      while (lock.fetch_sub(1, std::memory_order_acquire) != 1)
+          for (int cnt = 0; lock.load(std::memory_order_relaxed) <= 0; ++cnt)
+              if (cnt >= 10000) std::this_thread::yield(); // Be nice to hyperthreading
   }
   void release() { lock.store(1, std::memory_order_release); }
 };
@@ -98,8 +97,9 @@ struct ThreadBase {
   void wait_for(volatile const bool& b);
 
   std::thread nativeThread;
-  std::mutex mutex;
-  std::condition_variable sleepCondition;
+  Mutex mutex;
+  Spinlock spinlock;
+  ConditionVariable sleepCondition;
   volatile bool exit = false;
 };
 
@@ -137,6 +137,7 @@ struct Thread : public ThreadBase {
 
 struct MainThread : public Thread {
   virtual void idle_loop();
+  void join();
   volatile bool thinking = true; // Avoid a race with start_thinking()
 };
 
@@ -162,12 +163,9 @@ struct ThreadPool : public std::vector<Thread*> {
   MainThread* main() { return static_cast<MainThread*>(at(0)); }
   void read_uci_options();
   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;
   TimerThread* timer;
 };