-// ThreadsManager::start_thinking() is used by UI thread to wake up the main
-// thread parked in main_loop() and starting a new search. If asyncMode is true
-// then function returns immediately, otherwise caller is blocked waiting for
-// the search to finish.
-
-void ThreadsManager::start_thinking(const Position& pos, const LimitsType& limits,
- const std::set<Move>& searchMoves, bool async) {
- Thread& main = threads[0];
-
- lock_grab(main.sleepLock);
-
- // Wait main thread has finished before to launch a new search
- while (!main.do_sleep)
- cond_wait(sleepCond, main.sleepLock);
-
- // Copy input arguments to initialize the search
- RootPosition.copy(pos, 0);
- Limits = limits;
- RootMoves.clear();
-
- // Populate RootMoves with all the legal moves (default) or, if a searchMoves
- // set is given, with the subset of legal moves to search.
- for (MoveList<MV_LEGAL> ml(pos); !ml.end(); ++ml)
- if (searchMoves.empty() || searchMoves.count(ml.move()))
- RootMoves.push_back(RootMove(ml.move()));
-
- // Reset signals before to start the new search
- Signals.stopOnPonderhit = Signals.firstRootMove = false;
- Signals.stop = Signals.failedLowAtRoot = false;
-
- main.do_sleep = false;
- cond_signal(main.sleepCond); // Wake up main thread and start searching
+ // 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 the helpful master concept, a master can help only a sub-tree of its
+ // split point and because everything is finished here, it's not possible
+ // for the master to be 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::available_to().
+ Threads.mutex.lock();
+ sp.mutex.lock();
+ }