Don't use do_sleep flag

[stockfish] / src / thread.cpp

diff --git a/src/thread.cpp b/src/thread.cpp
index b11447dfc175f41180fc3d2a265c215ad79b8372..7f5ce7148f3fe25c5d243f7ff43d9b8cafc0a5b0 100644 (file)
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -50,7 +50,7 @@ Thread::Thread(Fn fn) : splitPoints() {
   start_fn = fn;
   idx = Threads.size();
 
-  do_sleep = (fn != &Thread::main_loop); // Avoid a race with start_searching()
+  is_finished = (fn != &Thread::main_loop); // Avoid a race with start_searching()
 
   if (!thread_create(handle, start_routine, this))
   {
@@ -64,7 +64,7 @@ Thread::Thread(Fn fn) : splitPoints() {
 
 Thread::~Thread() {
 
-  assert(do_sleep);
+  assert(is_finished);
 
   do_exit = true; // Search must be already finished
   notify_one();
@@ -81,7 +81,8 @@ void Thread::timer_loop() {
   while (!do_exit)
   {
       mutex.lock();
-      sleepCondition.wait_for(mutex, maxPly ? maxPly : INT_MAX);
+      while (!maxPly && !do_exit)
+          sleepCondition.wait_for(mutex, maxPly ? maxPly : INT_MAX);
       mutex.unlock();
       check_time();
   }
@@ -97,10 +98,10 @@ void Thread::main_loop() {
   {
       mutex.lock();
 
-      do_sleep = true; // Always return to sleep after a search
+      is_finished = true; // Always return to sleep after a search
       is_searching = false;
 
-      while (do_sleep && !do_exit)
+      while (is_finished && !do_exit)
       {
           Threads.sleepCondition.notify_one(); // Wake up UI thread if needed
           sleepCondition.wait(mutex);
@@ -131,17 +132,12 @@ void Thread::notify_one() {
 }
 
 
-// Thread::wait_for_stop() is called when the maximum depth is reached while
-// the program is pondering. The point is to work around a wrinkle in the UCI
-// protocol: When pondering, the engine is not allowed to give a "bestmove"
-// before the GUI sends it a "stop" or "ponderhit" command. We simply wait here
-// until one of these commands (that raise Signals.stop) is sent and
-// then return, after which the bestmove and pondermove will be printed.
+// Thread::wait_for() set the thread to sleep until condition 'b' turns true
 
-void Thread::wait_for_stop() {
+void Thread::wait_for(volatile const bool& b) {
 
   mutex.lock();
-  while (!Signals.stop) sleepCondition.wait(mutex);
+  while (!b) sleepCondition.wait(mutex);
   mutex.unlock();
 }
 
@@ -190,6 +186,7 @@ void ThreadPool::init() {
 
   timer = new Thread(&Thread::timer_loop);
   threads.push_back(new Thread(&Thread::main_loop));
+  sleepWhileIdle = true;
   read_uci_options();
 }
 
@@ -214,7 +211,6 @@ void ThreadPool::read_uci_options() {
 
   maxThreadsPerSplitPoint = Options["Max Threads per Split Point"];
   minimumSplitDepth       = Options["Min Split Depth"] * ONE_PLY;
-  useSleepingThreads      = Options["Use Sleeping Threads"];
   size_t requested        = Options["Threads"];
 
   assert(requested > 0);
@@ -230,34 +226,6 @@ void ThreadPool::read_uci_options() {
 }
 
 
-// wake_up() is called before a new search to start the threads that are waiting
-// on the sleep condition and to reset maxPly. When useSleepingThreads is set
-// threads will be woken up at split time.
-
-void ThreadPool::wake_up() const {
-
-  for (size_t i = 0; i < threads.size(); i++)
-  {
-      threads[i]->maxPly = 0;
-      threads[i]->do_sleep = false;
-
-      if (!useSleepingThreads)
-          threads[i]->notify_one();
-  }
-}
-
-
-// sleep() is called after the search finishes to ask all the threads but the
-// main one to go waiting on a sleep condition.
-
-void ThreadPool::sleep() const {
-
-  // Main thread will go to sleep by itself to avoid a race with start_searching()
-  for (size_t i = 1; i < threads.size(); i++)
-      threads[i]->do_sleep = true;
-}
-
-
 // available_slave_exists() tries to find an idle thread which is available as
 // a slave for the thread 'master'.
 
@@ -271,16 +239,6 @@ bool ThreadPool::available_slave_exists(Thread* master) const {
 }
 
 
-// set_timer() is used to set the timer to trigger after msec milliseconds.
-// If msec is 0 then timer is stopped.
-
-void ThreadPool::set_timer(int msec) {
-
-  timer->maxPly = msec;
-  timer->notify_one(); // Wake up and restart the timer
-}
-
-
 // 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, or because we have no unused split
@@ -344,9 +302,7 @@ Value ThreadPool::split(Position& pos, Stack* ss, Value alpha, Value beta,
           sp.slavesMask |= 1ULL << i;
           threads[i]->curSplitPoint = &sp;
           threads[i]->is_searching = true; // Slave leaves idle_loop()
-
-          if (useSleepingThreads)
-              threads[i]->notify_one();
+          threads[i]->notify_one(); // Could be sleeping
 
           if (++slavesCnt + 1 >= maxThreadsPerSplitPoint) // Master is always included
               break;
@@ -400,7 +356,7 @@ void ThreadPool::wait_for_search_finished() {
 
   Thread* t = main_thread();
   t->mutex.lock();
-  while (!t->do_sleep) sleepCondition.wait(t->mutex);
+  while (!t->is_finished) sleepCondition.wait(t->mutex);
   t->mutex.unlock();
 }
 
@@ -426,6 +382,6 @@ void ThreadPool::start_searching(const Position& pos, const LimitsType& limits,
       if (searchMoves.empty() || count(searchMoves.begin(), searchMoves.end(), ml.move()))
           RootMoves.push_back(RootMove(ml.move()));
 
-  main_thread()->do_sleep = false;
-  main_thread()->notify_one();
+  main_thread()->is_finished = false;
+  main_thread()->notify_one(); // Starts main thread
 }