Reformat and simplify previous patch

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 60d1a86866d74b4cd3753cdc3df80ff78c525fd5..1d40f8a070bfbe9f64ccd85355985aa54a769916 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -987,7 +987,7 @@ moves_loop: // When in check and at SpNode search starts from here
           &&  Threads.size() >= 2
           &&  depth >= Threads.minimumSplitDepth
           &&  (   !thisThread->activeSplitPoint
-               || !thisThread->activeSplitPoint->allowLatejoin)
+               || !thisThread->activeSplitPoint->allSlavesSearching)
           &&  thisThread->splitPointsSize < MAX_SPLITPOINTS_PER_THREAD)
       {
           assert(bestValue > -VALUE_INFINITE && bestValue < beta);
@@ -1529,9 +1529,10 @@ void Thread::idle_loop() {
 
           assert(searching);
 
+          searching = false;
           activePosition = NULL;
           sp->slavesMask.reset(idx);
-          sp->allowLatejoin = false;
+          sp->allSlavesSearching = false;
           sp->nodes += pos.nodes_searched();
 
           // Wake up the master thread so to allow it to return from the idle
@@ -1550,9 +1551,36 @@ void Thread::idle_loop() {
           // if we are exiting there is a chance that they are already freed.
           sp->mutex.unlock();
 
-          // Try to late join to another splitpoint
-          if (Threads.size() <= 2 || !attempt_to_latejoin()) // FIXME: attempt_to_latejoin() is theoretically unsafe when were are exiting the program...
-              searching = false;
+          // Try to late join to another split point if none of its slaves has
+          // already finished.
+          if (Threads.size() > 2)
+              for (size_t i = 0; i < Threads.size(); ++i)
+              {
+                  int size = Threads[i]->splitPointsSize; // Local copy
+                  sp = size ? &Threads[i]->splitPoints[size - 1] : NULL;
+
+                  if (   sp
+                      && sp->allSlavesSearching
+                      && available_to(Threads[i]))
+                  {
+                      // Recheck the conditions under lock protection
+                      Threads.mutex.lock();
+                      sp->mutex.lock();
+
+                      if (   sp->allSlavesSearching
+                          && available_to(Threads[i]))
+                      {
+                           sp->slavesMask.set(idx);
+                           activeSplitPoint = sp;
+                           searching = true;
+                      }
+
+                      sp->mutex.unlock();
+                      Threads.mutex.unlock();
+
+                      break; // Just a single attempt
+                  }
+              }
       }
 
       // If this thread is the master of a split point and all slaves have finished
@@ -1568,44 +1596,6 @@ void Thread::idle_loop() {
   }
 }
 
-bool Thread::attempt_to_latejoin()
-{
-    SplitPoint *sp;
-    size_t i;
-    bool success = false;
-
-    for (i = 0; i < Threads.size(); ++i)
-    {
-        int size = Threads[i]->splitPointsSize; // Make a local copy to prevent size from changing under our feet.
-
-        sp = size ? &Threads[i]->splitPoints[size - 1] : NULL;
-
-        if (   sp
-            && sp->allowLatejoin
-            && available_to(Threads[i], true))
-            break;
-    }
-
-    if (i == Threads.size())
-        return false; // No suitable splitpoint found!
-
-    // Recheck conditions under lock protection
-    Threads.mutex.lock();
-    sp->mutex.lock();
-
-    if (   sp->allowLatejoin
-        && available_to(Threads[i], true))
-    {
-         activeSplitPoint = sp;
-         sp->slavesMask.set(this->idx);
-         success = true;
-    }
-
-    sp->mutex.unlock();
-    Threads.mutex.unlock();
-
-    return success;
-}
 
 /// check_time() is called by the timer thread when the timer triggers. It is
 /// used to print debug info and, more importantly, to detect when we are out of