Split() clean up locking

Only unlock and relock when idle_loop() is actually called

No functional change

diff --git a/src/thread.cpp b/src/thread.cpp
index 51b250273e58f55ead15dab783883eef4737a0f7..f5b8b5e275aff3313b74ae061fd8b4455d98dab8 100644 (file)
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -303,28 +303,28 @@ void Thread::split(Position& pos, Stack* ss, Value alpha, Value beta, Value* bes
       slave->notify_one(); // Could be sleeping
   }
 
       slave->notify_one(); // Could be sleeping
   }
 

-  sp.mutex.unlock();
-  Threads.mutex.unlock();
-

   // Everything is set up. The master thread enters the idle loop, from which
   // it will instantly launch a search, because its 'searching' flag is set.
   // The thread will return from the idle loop when all slaves have finished
   // their work at this split point.
   if (slavesCnt > 1 || Fake)
   {
   // Everything is set up. The master thread enters the idle loop, from which
   // it will instantly launch a search, because its 'searching' flag is set.
   // The thread will return from the idle loop when all slaves have finished
   // their work at this split point.
   if (slavesCnt > 1 || Fake)
   {

+      sp.mutex.unlock();
+      Threads.mutex.unlock();
+

       Thread::idle_loop(); // Force a call to base class idle_loop()
 
       // In helpful master concept a master can help only a sub-tree of its split
       // point, and because here is all finished is not possible master is booked.
       assert(!searching);
       assert(!activePosition);
       Thread::idle_loop(); // Force a call to base class idle_loop()
 
       // In helpful master concept a master can help only a sub-tree of its split
       // point, and because here is all finished is not possible master is booked.
       assert(!searching);
       assert(!activePosition);

-  }

 
 

-  // We have returned from the idle loop, which means that all threads are
-  // finished. Note that setting 'searching' and decreasing splitPointsSize is
-  // done under lock protection to avoid a race with Thread::is_available_to().
-  Threads.mutex.lock();
-  sp.mutex.lock();
+      // We have returned from the idle loop, which means that all threads are
+      // finished. Note that setting 'searching' and decreasing splitPointsSize is
+      // done under lock protection to avoid a race with Thread::is_available_to().
+      Threads.mutex.lock();
+      sp.mutex.lock();
+  }

 
   searching = true;
   splitPointsSize--;
 
   searching = true;
   splitPointsSize--;