X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fthread.cpp;h=c76b4b707e9f97dfe641670de06021b982481287;hp=d8740db2a66c39f04e49171cc7991e7d0e75b4f8;hb=9c9205860c5ab0e4f3180298e3f7082be259772c;hpb=81c7975dcdf37ec96d308f800c2a40f6cb08907e

diff --git a/src/thread.cpp b/src/thread.cpp
index d8740db2..c76b4b70 100644
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -29,18 +29,16 @@ using namespace Search;
 
 ThreadPool Threads; // Global object
 
-extern void check_time();
-
 namespace {
 
- // Helpers to launch a thread after creation and joining before delete. Must be
- // outside Thread c'tor and d'tor because the object must be fully initialized
+ // Helpers to launch a thread after creation and joining before delete. Outside the
+ // Thread constructor and destructor because the object must be fully initialized
  // when start_routine (and hence virtual idle_loop) is called and when joining.
 
  template<typename T> T* new_thread() {
-   T* th = new T();
-   th->nativeThread = std::thread(&ThreadBase::idle_loop, th); // Will go to sleep
-   return th;
+   std::thread* th = new T;
+   *th = std::thread(&T::idle_loop, (T*)th); // Will go to sleep
+   return (T*)th;
  }
 
  void delete_thread(ThreadBase* th) {
@@ -50,7 +48,7 @@ namespace {
    th->mutex.unlock();
 
    th->notify_one();
-   th->nativeThread.join(); // Wait for thread termination
+   th->join(); // Wait for thread termination
    delete th;
  }
 
@@ -61,180 +59,56 @@ namespace {
 
 void ThreadBase::notify_one() {
 
-  std::unique_lock<Mutex>(this->mutex);
+  std::unique_lock<Mutex> lk(mutex);
   sleepCondition.notify_one();
 }
 
 
-// ThreadBase::wait_for() set the thread to sleep until 'condition' turns true
+// ThreadBase::wait() set the thread to sleep until 'condition' turns true
 
-void ThreadBase::wait_for(volatile const bool& condition) {
+void ThreadBase::wait(std::atomic_bool& condition) {
 
   std::unique_lock<Mutex> lk(mutex);
-  sleepCondition.wait(lk, [&]{ return condition; });
+  sleepCondition.wait(lk, [&]{ return bool(condition); });
 }
 
 
-// Thread c'tor makes some init but does not launch any execution thread that
-// will be started only when c'tor returns.
-
-Thread::Thread() /* : splitPoints() */ { // Initialization of non POD broken in MSVC
-
-  searching = false;
-  maxPly = 0;
-  splitPointsSize = 0;
-  activeSplitPoint = nullptr;
-  activePosition = nullptr;
-  idx = Threads.size(); // Starts from 0
-}
-
-
-// Thread::cutoff_occurred() checks whether a beta cutoff has occurred in the
-// current active split point, or in some ancestor of the split point.
-
-bool Thread::cutoff_occurred() const {
-
-  for (SplitPoint* sp = activeSplitPoint; sp; sp = sp->parentSplitPoint)
-      if (sp->cutoff)
-          return true;
-
-  return false;
-}
-
+// ThreadBase::wait_while() set the thread to sleep until 'condition' turns false
+void ThreadBase::wait_while(std::atomic_bool& condition) {
 
-// Thread::can_join() checks whether the thread is available to join the split
-// point 'sp'. An obvious requirement is that thread must be idle. With more than
-// two threads, this is not sufficient: If the thread is the master of some split
-// point, it is only available as a slave for the split points below his active
-// one (the "helpful master" concept in YBWC terminology).
-
-bool Thread::can_join(const SplitPoint* sp) const {
-
-  if (searching)
-      return false;
-
-  // Make a local copy to be sure it doesn't become zero under our feet while
-  // testing next condition and so leading to an out of bounds access.
-  const size_t size = splitPointsSize;
-
-  // No split points means that the thread is available as a slave for any
-  // other thread otherwise apply the "helpful master" concept if possible.
-  return !size || splitPoints[size - 1].slavesMask.test(sp->master->idx);
+  std::unique_lock<Mutex> lk(mutex);
+  sleepCondition.wait(lk, [&]{ return !condition; });
 }
 
 
-// Thread::split() does the actual work of distributing the work at a node between
-// several available threads. If it does not succeed in splitting the node
-// (because no idle threads are available), the function immediately returns.
-// If splitting is possible, a SplitPoint object is initialized with all the
-// data that must be copied to the helper threads and then helper threads are
-// informed that they have been assigned work. This will cause them to instantly
-// leave their idle loops and call search(). When all threads have returned from
-// search() then split() returns.
-
-void Thread::split(Position& pos, Stack* ss, Value alpha, Value beta, Value* bestValue,
-                   Move* bestMove, Depth depth, int moveCount,
-                   MovePicker* movePicker, int nodeType, bool cutNode) {
-
-  assert(searching);
-  assert(-VALUE_INFINITE < *bestValue && *bestValue <= alpha && alpha < beta && beta <= VALUE_INFINITE);
-  assert(depth >= Threads.minimumSplitDepth);
-  assert(splitPointsSize < MAX_SPLITPOINTS_PER_THREAD);
-
-  // Pick and init the next available split point
-  SplitPoint& sp = splitPoints[splitPointsSize];
-
-  sp.mutex.lock(); // No contention here until we don't increment splitPointsSize
-
-  sp.master = this;
-  sp.parentSplitPoint = activeSplitPoint;
-  sp.slavesMask = 0, sp.slavesMask.set(idx);
-  sp.depth = depth;
-  sp.bestValue = *bestValue;
-  sp.bestMove = *bestMove;
-  sp.alpha = alpha;
-  sp.beta = beta;
-  sp.nodeType = nodeType;
-  sp.cutNode = cutNode;
-  sp.movePicker = movePicker;
-  sp.moveCount = moveCount;
-  sp.pos = &pos;
-  sp.nodes = 0;
-  sp.cutoff = false;
-  sp.ss = ss;
-  sp.allSlavesSearching = true; // Must be set under lock protection
-
-  ++splitPointsSize;
-  activeSplitPoint = &sp;
-  activePosition = nullptr;
-
-  // Try to allocate available threads
-  Thread* slave;
-
-  while (    sp.slavesMask.count() < MAX_SLAVES_PER_SPLITPOINT
-         && (slave = Threads.available_slave(&sp)) != nullptr)
-  {
-     slave->mutex.lock();
-
-      if (slave->can_join(activeSplitPoint))
-      {
-          activeSplitPoint->slavesMask.set(slave->idx);
-          slave->activeSplitPoint = activeSplitPoint;
-          slave->searching = true;
-          slave->sleepCondition.notify_one(); // Could be sleeping
-      }
-
-      slave->mutex.unlock();
-  }
-
-  // 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.
-  sp.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);
-
-  searching = true;
-
-  // We have returned from the idle loop, which means that all threads are
-  // finished. Note that decreasing splitPointsSize must be done under lock
-  // protection to avoid a race with Thread::can_join().
-  sp.mutex.lock();
+// Thread constructor makes some init but does not launch any execution thread,
+// which will be started only when the constructor returns.
 
-  --splitPointsSize;
-  activeSplitPoint = sp.parentSplitPoint;
-  activePosition = &pos;
-  pos.set_nodes_searched(pos.nodes_searched() + sp.nodes);
-  *bestMove = sp.bestMove;
-  *bestValue = sp.bestValue;
+Thread::Thread() {
 
-  sp.mutex.unlock();
+  searching = resetCallsCnt = false;
+  maxPly = callsCnt = 0;
+  history.clear();
+  counterMoves.clear();
+  idx = Threads.size(); // Starts from 0
 }
 
 
-// TimerThread::idle_loop() is where the timer thread waits Resolution milliseconds
-// and then calls check_time(). When not searching, thread sleeps until it's woken up.
+// Thread::idle_loop() is where the thread is parked when it has no work to do
 
-void TimerThread::idle_loop() {
+void Thread::idle_loop() {
 
   while (!exit)
   {
       std::unique_lock<Mutex> lk(mutex);
 
-      if (!exit)
-          sleepCondition.wait_for(lk, std::chrono::milliseconds(run ? Resolution : INT_MAX));
+      while (!searching && !exit)
+          sleepCondition.wait(lk);
 
       lk.unlock();
 
-      if (run)
-          check_time();
+      if (!exit && searching)
+          search();
   }
 }
 
@@ -252,48 +126,48 @@ void MainThread::idle_loop() {
 
       while (!thinking && !exit)
       {
-          Threads.sleepCondition.notify_one(); // Wake up the UI thread if needed
+          sleepCondition.notify_one(); // Wake up the UI thread if needed
           sleepCondition.wait(lk);
       }
 
       lk.unlock();
 
       if (!exit)
-      {
-          searching = true;
+          think();
+  }
+}
 
-          Search::think();
 
-          assert(searching);
+// MainThread::join() waits for main thread to finish thinking
 
-          searching = false;
-      }
-  }
+void MainThread::join() {
+
+  std::unique_lock<Mutex> lk(mutex);
+  sleepCondition.wait(lk, [&]{ return !thinking; });
 }
 
 
 // ThreadPool::init() is called at startup to create and launch requested threads,
-// that will go immediately to sleep. We cannot use a c'tor because Threads is a
-// static object and we need a fully initialized engine at this point due to
-// allocation of Endgames in Thread c'tor.
+// that will go immediately to sleep. We cannot use a constructor because Threads
+// is a static object and we need a fully initialized engine at this point due to
+// allocation of Endgames in the Thread constructor.
 
 void ThreadPool::init() {
 
-  timer = new_thread<TimerThread>();
   push_back(new_thread<MainThread>());
   read_uci_options();
 }
 
 
 // ThreadPool::exit() terminates the threads before the program exits. Cannot be
-// done in d'tor because threads must be terminated before freeing us.
+// done in destructor because threads must be terminated before freeing us.
 
 void ThreadPool::exit() {
 
-  delete_thread(timer); // As first because check_time() accesses threads data
-
   for (Thread* th : *this)
       delete_thread(th);
+
+  clear(); // Get rid of stale pointers
 }
 
 
@@ -305,15 +179,10 @@ void ThreadPool::exit() {
 
 void ThreadPool::read_uci_options() {
 
-  minimumSplitDepth = Options["Min Split Depth"] * ONE_PLY;
   size_t requested  = Options["Threads"];
 
   assert(requested > 0);
 
-  // If zero (default) then set best minimum split depth automatically
-  if (!minimumSplitDepth)
-      minimumSplitDepth = requested < 8 ? 4 * ONE_PLY : 7 * ONE_PLY;
-
   while (size() < requested)
       push_back(new_thread<Thread>());
 
@@ -325,25 +194,14 @@ void ThreadPool::read_uci_options() {
 }
 
 
-// ThreadPool::available_slave() tries to find an idle thread which is available
-// to join SplitPoint 'sp'.
-
-Thread* ThreadPool::available_slave(const SplitPoint* sp) const {
-
-  for (Thread* th : *this)
-      if (th->can_join(sp))
-          return th;
-
-  return nullptr;
-}
-
-
-// ThreadPool::wait_for_think_finished() waits for main thread to finish the search
+// ThreadPool::nodes_searched() returns the number of nodes searched
 
-void ThreadPool::wait_for_think_finished() {
+int64_t ThreadPool::nodes_searched() {
 
-  std::unique_lock<Mutex> lk(main()->mutex);
-  sleepCondition.wait(lk, [&]{ return !main()->thinking; });
+  int64_t nodes = 0;
+  for (Thread *th : *this)
+      nodes += th->rootPos.nodes_searched();
+  return nodes;
 }
 
 
@@ -352,15 +210,13 @@ void ThreadPool::wait_for_think_finished() {
 
 void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits,
                                 StateStackPtr& states) {
-  wait_for_think_finished();
-
-  SearchTime = now(); // As early as possible
+  main()->join();
 
   Signals.stopOnPonderhit = Signals.firstRootMove = false;
   Signals.stop = Signals.failedLowAtRoot = false;
 
-  RootMoves.clear();
-  RootPos = pos;
+  main()->rootMoves.clear();
+  main()->rootPos = pos;
   Limits = limits;
   if (states.get()) // If we don't set a new position, preserve current state
   {
@@ -371,8 +227,8 @@ void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits,
   for (const auto& m : MoveList<LEGAL>(pos))
       if (   limits.searchmoves.empty()
           || std::count(limits.searchmoves.begin(), limits.searchmoves.end(), m))
-          RootMoves.push_back(RootMove(m));
+          main()->rootMoves.push_back(RootMove(m));
 
   main()->thinking = true;
-  main()->notify_one(); // Starts main thread
+  main()->notify_one(); // Wake up main thread: 'thinking' must be already set
 }