X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fthread.cpp;h=eb64f7ee372151ec5966d08477f9b9a040b3ef78;hp=ef5ae857e30580822b5c05cf2406a413a6eb05f6;hb=00d9e9fd283b31e63389af091b158dbc3fedfc0e;hpb=be77406a55d1840862237cffe153dc08a83108d3

diff --git a/src/thread.cpp b/src/thread.cpp
index ef5ae857..eb64f7ee 100644
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -66,174 +66,71 @@ void ThreadBase::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); });
+}
+
+
+// ThreadBase::wait_while() set the thread to sleep until 'condition' turns false
+void ThreadBase::wait_while(std::atomic<bool>& condition) {
+
+  std::unique_lock<Mutex> lk(mutex);
+  sleepCondition.wait(lk, [&]{ return !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
+Thread::Thread() {
 
   searching = false;
   maxPly = 0;
-  splitPointsSize = 0;
-  activeSplitPoint = nullptr;
-  activePosition = nullptr;
+  history.clear();
+  counterMoves.clear();
   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;
-}
-
-
-// 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);
-}
+// 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.
 
+void TimerThread::idle_loop() {
 
-// 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.spinlock.acquire(); // 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)
+  while (!exit)
   {
-     slave->spinlock.acquire();
-
-      if (slave->can_join(activeSplitPoint))
-      {
-          activeSplitPoint->slavesMask.set(slave->idx);
-          slave->activeSplitPoint = activeSplitPoint;
-          slave->searching = true;
-      }
-
-      slave->spinlock.release();
-  }
-
-  // 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.spinlock.release();
-
-  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;
+      std::unique_lock<Mutex> lk(mutex);
 
-  // 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.spinlock.acquire();
+      if (!exit)
+          sleepCondition.wait_for(lk, std::chrono::milliseconds(run ? Resolution : INT_MAX));
 
-  --splitPointsSize;
-  activeSplitPoint = sp.parentSplitPoint;
-  activePosition = &pos;
-  pos.set_nodes_searched(pos.nodes_searched() + sp.nodes);
-  *bestMove = sp.bestMove;
-  *bestValue = sp.bestValue;
+      lk.unlock();
 
-  sp.spinlock.release();
+      if (!exit && run)
+          check_time();
+  }
 }
 
 
-// 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();
   }
 }
 
@@ -258,20 +155,12 @@ void MainThread::idle_loop() {
       lk.unlock();
 
       if (!exit)
-      {
-          searching = true;
-
-          Search::think();
-
-          assert(searching);
-
-          searching = false;
-      }
+          think();
   }
 }
 
 
-// MainThread::join() waits for main thread to finish the search
+// MainThread::join() waits for main thread to finish thinking
 
 void MainThread::join() {
 
@@ -299,9 +188,12 @@ void ThreadPool::init() {
 void ThreadPool::exit() {
 
   delete_thread(timer); // As first because check_time() accesses threads data
+  timer = nullptr;
 
   for (Thread* th : *this)
       delete_thread(th);
+
+  clear(); // Get rid of stale pointers
 }
 
 
@@ -313,15 +205,10 @@ 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>());
 
@@ -333,16 +220,14 @@ void ThreadPool::read_uci_options() {
 }
 
 
-// ThreadPool::available_slave() tries to find an idle thread which is available
-// to join SplitPoint 'sp'.
+// ThreadPool::nodes_searched() returns the number of nodes searched
 
-Thread* ThreadPool::available_slave(const SplitPoint* sp) const {
+int64_t ThreadPool::nodes_searched() {
 
-  for (Thread* th : *this)
-      if (th->can_join(sp))
-          return th;
-
-  return nullptr;
+  int64_t nodes = 0;
+  for (Thread *th : *this)
+      nodes += th->rootPos.nodes_searched();
+  return nodes;
 }
 
 
@@ -353,13 +238,11 @@ void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits,
                                 StateStackPtr& states) {
   main()->join();
 
-  SearchTime = now(); // As early as possible
-
   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
   {
@@ -370,7 +253,7 @@ 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(); // Wake up main thread: 'thinking' must be already set