Reduce variation in rootDepth between different threads

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 78e4748f5ce64a51efbd2b33821f3579b8d87097..fff9144d93152b1a7fd0469bdffa3d63877960c8 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -37,7 +37,7 @@
 
 namespace Search {
 
-  volatile SignalsType Signals;
+  SignalsType Signals;
   LimitsType Limits;
   StateStackPtr SetupStates;
 }
@@ -376,7 +376,7 @@ void Thread::search(bool isMainThread) {
   {
       // Set up the new depth for the helper threads
       if (!isMainThread)
-          rootDepth = Threads.main()->rootDepth + Depth(int(3 * log(1 + this->idx)));
+          rootDepth = Threads.main()->rootDepth + Depth(int(2.2 * log(1 + this->idx)));
 
       // Age out PV variability metric
       if (isMainThread)
@@ -539,12 +539,7 @@ void Thread::search(bool isMainThread) {
 
 namespace {
 
-  // search<>() is the main search function for both PV and non-PV nodes and for
-  // normal and SplitPoint nodes. When called just after a split point the search
-  // is simpler because we have already probed the hash table, done a null move
-  // search, and searched the first move before splitting, so we don't have to
-  // repeat all this work again. We also don't need to store anything to the hash
-  // table here: This is taken care of after we return from the split point.
+  // search<>() is the main search function for both PV and non-PV nodes
 
   template <NodeType NT>
   Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode) {
@@ -581,8 +576,8 @@ namespace {
     if (!RootNode)
     {
         // Step 2. Check for aborted search and immediate draw
-        if (Signals.stop || pos.is_draw() || ss->ply >= MAX_PLY)
-            return ss->ply >= MAX_PLY && !inCheck ? evaluate(pos)
+        if (Signals.stop.load(std::memory_order_relaxed) || pos.is_draw() || ss->ply >= MAX_PLY)
+            return ss->ply >= MAX_PLY && !inCheck ? evaluate(pos) 
                                                   : DrawValue[pos.side_to_move()];
 
         // Step 3. Mate distance pruning. Even if we mate at the next move our score
@@ -841,7 +836,7 @@ moves_loop: // When in check search starts from here
 
       if (RootNode && thisThread == Threads.main())
       {
-          Signals.firstRootMove = (moveCount == 1);
+          Signals.firstRootMove = moveCount == 1;
 
           if (Time.elapsed() > 3000)
               sync_cout << "info depth " << depth / ONE_PLY
@@ -1008,7 +1003,7 @@ moves_loop: // When in check search starts from here
       // Finished searching the move. If a stop occurred, the return value of
       // the search cannot be trusted, and we return immediately without
       // updating best move, PV and TT.
-      if (Signals.stop)
+      if (Signals.stop.load(std::memory_order_relaxed))
           return VALUE_ZERO;
 
       if (RootNode)
@@ -1577,7 +1572,7 @@ void check_time() {
   {
       bool stillAtFirstMove =    Signals.firstRootMove
                              && !Signals.failedLowAtRoot
-                             &&  elapsed > Time.available() * 75 / 100;
+                             &&  elapsed > Time.available() * 3 / 4;
 
       if (   stillAtFirstMove
           || elapsed > Time.maximum() - 2 * TimerThread::Resolution)