Retire set_timer()

Also assure in Thread::timer_loop() that when
timer interval is 0 (timer is disabled) we
never call check_time()

No functional change.

src/search.cpp

@@ -239,17 +239,16 @@ void Search::think() {
 
   // Set best timer interval to avoid lagging under time pressure. Timer is
   // used to check for remaining available thinking time.
-  if (Limits.use_time_management())
-      Threads.set_timer(std::min(100, std::max(TimeMgr.available_time() / 16,
-                                               TimerResolution)));
-  else if (Limits.nodes)
-      Threads.set_timer(2 * TimerResolution);
-  else
-      Threads.set_timer(100);
+  Threads.timer_thread()->maxPly = /* Hack: we use maxPly to set timer interval */
+  Limits.use_time_management() ? std::min(100, std::max(TimeMgr.available_time() / 16, TimerResolution)) :
+                  Limits.nodes ? 2 * TimerResolution
+                               : 100;
+
+  Threads.timer_thread()->notify_one(); // Wake up the recurring timer
 
   id_loop(RootPos); // Let's start searching !
 
-  Threads.set_timer(0); // Stop timer
+  Threads.timer_thread()->maxPly = 0; // Stop the timer
 
   // Main thread will go to sleep by itself to avoid a race with start_searching()
   for (size_t i = 0; i < Threads.size(); i++)

src/thread.cpp

@@ -80,7 +80,8 @@ 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();
   }
@@ -237,16 +238,6 @@ 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

src/thread.h

@@ -140,10 +140,10 @@ public:
   int min_split_depth() const { return minimumSplitDepth; }
   size_t size() const { return threads.size(); }
   Thread* main_thread() { return threads[0]; }
+  Thread* timer_thread() { return timer; }
 
   void read_uci_options();
   bool available_slave_exists(Thread* master) const;
-  void set_timer(int msec);
   void wait_for_search_finished();
   void start_searching(const Position&, const Search::LimitsType&,
                        const std::vector<Move>&, Search::StateStackPtr&);