Use thread specific mutexes instead of a global one.

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index a6f4d6bdd462d13a2472b8abd444f9b17881c554..501d6c60b447f5b132ddcc6ef3a307b47d8235dd 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -765,7 +765,7 @@ moves_loop: // When in check and at SpNode search starts from here
               continue;
 
           moveCount = ++splitPoint->moveCount;
-          splitPoint->spinlock.release();
+          splitPoint->mutex.unlock();
       }
       else
           ++moveCount;
@@ -834,7 +834,7 @@ moves_loop: // When in check and at SpNode search starts from here
               && moveCount >= FutilityMoveCounts[improving][depth])
           {
               if (SpNode)
-                  splitPoint->spinlock.acquire();
+                  splitPoint->mutex.lock();
 
               continue;
           }
@@ -853,7 +853,7 @@ moves_loop: // When in check and at SpNode search starts from here
 
                   if (SpNode)
                   {
-                      splitPoint->spinlock.acquire();
+                      splitPoint->mutex.lock();
                       if (bestValue > splitPoint->bestValue)
                           splitPoint->bestValue = bestValue;
                   }
@@ -865,7 +865,7 @@ moves_loop: // When in check and at SpNode search starts from here
           if (predictedDepth < 4 * ONE_PLY && pos.see_sign(move) < VALUE_ZERO)
           {
               if (SpNode)
-                  splitPoint->spinlock.acquire();
+                  splitPoint->mutex.lock();
 
               continue;
           }
@@ -965,7 +965,7 @@ moves_loop: // When in check and at SpNode search starts from here
       // Step 18. Check for new best move
       if (SpNode)
       {
-          splitPoint->spinlock.acquire();
+          splitPoint->mutex.lock();
           bestValue = splitPoint->bestValue;
           alpha = splitPoint->alpha;
       }
@@ -1526,13 +1526,12 @@ void Thread::idle_loop() {
       // If this thread has been assigned work, launch a search
       while (searching)
       {
-          Threads.spinlock.acquire();
+          mutex.lock();
 
           assert(activeSplitPoint);
-
           SplitPoint* sp = activeSplitPoint;
 
-          Threads.spinlock.release();
+          mutex.unlock();
 
           Stack stack[MAX_PLY+4], *ss = stack+2; // To allow referencing (ss-2) and (ss+2)
           Position pos(*sp->pos, this);
@@ -1540,7 +1539,7 @@ void Thread::idle_loop() {
           std::memcpy(ss-2, sp->ss-2, 5 * sizeof(Stack));
           ss->splitPoint = sp;
 
-          sp->spinlock.acquire();
+          sp->mutex.lock();
 
           assert(activePosition == nullptr);
 
@@ -1578,7 +1577,7 @@ void Thread::idle_loop() {
           // After releasing the lock we can't access any SplitPoint related data
           // in a safe way because it could have been released under our feet by
           // the sp master.
-          sp->spinlock.release();
+          sp->mutex.unlock();
 
           // Try to late join to another split point if none of its slaves has
           // already finished.
@@ -1593,7 +1592,7 @@ void Thread::idle_loop() {
               if (   sp
                   && sp->allSlavesSearching
                   && sp->slavesMask.count() < MAX_SLAVES_PER_SPLITPOINT
-                  && available_to(sp->master))
+                  && can_join(sp))
               {
                   assert(this != th);
                   assert(!(this_sp && this_sp->slavesMask.none()));
@@ -1618,25 +1617,29 @@ void Thread::idle_loop() {
               sp = bestSp;
 
               // Recheck the conditions under lock protection
-              Threads.spinlock.acquire();
-              sp->spinlock.acquire();
+              sp->mutex.lock();
 
               if (   sp->allSlavesSearching
-                  && sp->slavesMask.count() < MAX_SLAVES_PER_SPLITPOINT
-                  && available_to(sp->master))
+                  && sp->slavesMask.count() < MAX_SLAVES_PER_SPLITPOINT)
               {
-                  sp->slavesMask.set(idx);
-                  activeSplitPoint = sp;
-                  searching = true;
+                  mutex.lock();
+
+                  if (can_join(sp))
+                  {
+                      sp->slavesMask.set(idx);
+                      activeSplitPoint = sp;
+                      searching = true;
+                  }
+
+                  mutex.unlock();
               }
 
-              sp->spinlock.release();
-              Threads.spinlock.release();
+              sp->mutex.unlock();
           }
       }
 
       // Avoid races with notify_one() fired from last slave of the split point
-      std::unique_lock<std::mutex> lk(mutex);
+      std::unique_lock<Mutex> lk(mutex);
 
       // If we are master and all slaves have finished then exit idle_loop
       if (this_sp && this_sp->slavesMask.none())
@@ -1687,18 +1690,17 @@ void check_time() {
 
   else if (Limits.nodes)
   {
-      Threads.spinlock.acquire();
-
       int64_t nodes = RootPos.nodes_searched();
 
       // Loop across all split points and sum accumulated SplitPoint nodes plus
       // all the currently active positions nodes.
+      // FIXME: Racy...
       for (Thread* th : Threads)
           for (size_t i = 0; i < th->splitPointsSize; ++i)
           {
               SplitPoint& sp = th->splitPoints[i];
 
-              sp.spinlock.acquire();
+              sp.mutex.lock();
 
               nodes += sp.nodes;
 
@@ -1706,11 +1708,9 @@ void check_time() {
                   if (sp.slavesMask.test(idx) && Threads[idx]->activePosition)
                       nodes += Threads[idx]->activePosition->nodes_searched();
 
-              sp.spinlock.release();
+              sp.mutex.unlock();
           }
 
-      Threads.spinlock.release();
-
       if (nodes >= Limits.nodes)
           Signals.stop = true;
   }