Check for an available slave early on

mcostalba · mcostalba · commit ce1c260ea97c · 2014-06-09T04:56:31.000+09:00
Don't take the split lock if we don't have
available slaves (about 30-40% of times).

This new condition allows to retire the now
redundant one on number of threads.

No functional change.
diff --git a/src/search.cpp b/src/search.cpp
@@ -980,8 +980,8 @@ namespace {
 
       // Step 19. Check for splitting the search
       if (   !SpNode
-          &&  Threads.size() >= 2
           &&  depth >= Threads.minimumSplitDepth
+          &&  Threads.available_slave(thisThread)
           &&  (   !thisThread->activeSplitPoint
                || !thisThread->activeSplitPoint->allSlavesSearching)
           &&  thisThread->splitPointsSize < MAX_SPLITPOINTS_PER_THREAD)
