X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fthread.cpp;h=65d01d9100a874e19db9addea3772bafa735dd69;hp=9f5a13f8624dac701d3827ee0d2beefca76e8cf4;hb=3aa471f2a9cb;hpb=e4efc8b74159a77e77d0d6b53c9ef7215cfdcb9a

diff --git a/src/thread.cpp b/src/thread.cpp
index 9f5a13f8..65d01d91 100644
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -32,7 +32,7 @@ ThreadsManager Threads; // Global object
 namespace { extern "C" {
 
  // start_routine() is the C function which is called when a new thread
- // is launched. It is a wrapper to member function pointed by start_fn
+ // is launched. It is a wrapper to member function pointed by start_fn.
 
  long start_routine(Thread* th) { (th->*(th->start_fn))(); return 0; }
 
@@ -49,7 +49,8 @@ Thread::Thread(Fn fn) {
   curSplitPoint = NULL;
   start_fn = fn;
   threadID = Threads.size();
-  do_sleep = (threadID != 0); // Avoid a race with start_thinking()
+
+  do_sleep = (fn != &Thread::main_loop); // Avoid a race with start_searching()
 
   lock_init(sleepLock);
   cond_init(sleepCond);
@@ -65,7 +66,7 @@ Thread::Thread(Fn fn) {
 }
 
 
-// Thread d'tor will wait for thread termination before to return.
+// Thread d'tor waits for thread termination before to return.
 
 Thread::~Thread() {
 
@@ -85,7 +86,7 @@ Thread::~Thread() {
 
 
 // Thread::timer_loop() is where the timer thread waits maxPly milliseconds and
-// then calls do_timer_event(). If maxPly is 0 thread sleeps until is woken up.
+// then calls check_time(). If maxPly is 0 thread sleeps until is woken up.
 extern void check_time();
 
 void Thread::timer_loop() {
@@ -131,11 +132,12 @@ void Thread::main_loop() {
 
 
 // Thread::wake_up() wakes up the thread, normally at the beginning of the search
-// or, if "sleeping threads" is used, when there is some work to do.
+// or, if "sleeping threads" is used at split time.
 
 void Thread::wake_up() {
 
   lock_grab(sleepLock);
+  do_sleep = false;
   cond_signal(sleepCond);
   lock_release(sleepLock);
 }
@@ -153,16 +155,13 @@ void Thread::wait_for_stop_or_ponderhit() {
   Signals.stopOnPonderhit = true;
 
   lock_grab(sleepLock);
-
-  while (!Signals.stop)
-      cond_wait(sleepCond, sleepLock);
-
+  while (!Signals.stop) cond_wait(sleepCond, sleepLock);
   lock_release(sleepLock);
 }
 
 
-// cutoff_occurred() checks whether a beta cutoff has occurred in the current
-// active split point, or in some ancestor of the split point.
+// 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 {
 
@@ -174,12 +173,12 @@ bool Thread::cutoff_occurred() const {
 }
 
 
-// is_available_to() checks whether the thread is available to help the thread with
-// threadID "master" at a split point. An obvious requirement is that thread must be
-// idle. With more than two threads, this is not by itself sufficient: If the thread
-// is the master of some active split point, it is only available as a slave to the
-// threads which are busy searching the split point at the top of "slave"'s split
-// point stack (the "helpful master concept" in YBWC terminology).
+// Thread::is_available_to() checks whether the thread is available to help the
+// thread with threadID "master" at a split point. 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 active split point, it is only available as a
+// slave to the threads which are busy searching the split point at the top of
+// "slave"'s split point stack (the "helpful master concept" in YBWC terminology).
 
 bool Thread::is_available_to(int master) const {
 
@@ -196,6 +195,34 @@ bool Thread::is_available_to(int master) const {
 }
 
 
+// init() is called at startup. Initializes lock and condition variable and
+// launches requested threads sending them immediately to sleep. We cannot use
+// a c'tor becuase Threads is a static object and we need a fully initialized
+// engine at this point due to allocation of endgames in Thread c'tor.
+
+void ThreadsManager::init() {
+
+  cond_init(sleepCond);
+  lock_init(splitLock);
+  timer = new Thread(&Thread::timer_loop);
+  threads.push_back(new Thread(&Thread::main_loop));
+  read_uci_options();
+}
+
+
+// d'tor cleanly terminates the threads when the program exits.
+
+ThreadsManager::~ThreadsManager() {
+
+  for (int i = 0; i < size(); i++)
+      delete threads[i];
+
+  delete timer;
+  lock_destroy(splitLock);
+  cond_destroy(sleepCond);
+}
+
+
 // read_uci_options() updates internal threads parameters from the corresponding
 // UCI options and creates/destroys threads to match the requested number. Thread
 // objects are dynamically allocated to avoid creating in advance all possible
@@ -222,14 +249,13 @@ void ThreadsManager::read_uci_options() {
 
 
 // wake_up() is called before a new search to start the threads that are waiting
-// on the sleep condition. If useSleepingThreads is set threads will be woken up
-// at split time.
+// on the sleep condition and to reset maxPly. When useSleepingThreads is set
+// threads will be woken up at split time.
 
-void ThreadsManager::wake_up() {
+void ThreadsManager::wake_up() const {
 
   for (int i = 0; i < size(); i++)
   {
-      threads[i]->do_sleep = false;
       threads[i]->maxPly = 0;
 
       if (!useSleepingThreads)
@@ -238,39 +264,13 @@ void ThreadsManager::wake_up() {
 }
 
 
-// sleep() is called after the search to ask all the threads but the main to go
-// waiting on a sleep condition.
+// sleep() is called after the search finishes to ask all the threads but the
+// main one to go waiting on a sleep condition.
 
-void ThreadsManager::sleep() {
+void ThreadsManager::sleep() const {
 
   for (int i = 1; i < size(); i++) // Main thread will go to sleep by itself
-      threads[i]->do_sleep = true; // to avoid a race with start_thinking()
-}
-
-
-// init() is called during startup. Initializes locks and condition variables
-// and launches all threads sending them immediately to sleep.
-
-void ThreadsManager::init() {
-
-    cond_init(sleepCond);
-    lock_init(splitLock);
-    timer = new Thread(&Thread::timer_loop);
-    threads.push_back(new Thread(&Thread::main_loop));
-    read_uci_options();
-}
-
-
-// exit() is called to cleanly terminate the threads before the program finishes
-
-void ThreadsManager::exit() {
-
-  for (int i = 0; i < size(); i++)
-      delete threads[i];
-
-  delete timer;
-  lock_destroy(splitLock);
-  cond_destroy(sleepCond);
+      threads[i]->do_sleep = true; // to avoid a race with start_searching()
 }
 
 
@@ -412,63 +412,40 @@ void ThreadsManager::set_timer(int msec) {
 }
 
 
-// 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
+// ThreadsManager::wait_for_search_finished() waits for main thread to go to
+// sleep, this means search is finished. Then returns.
+
+void ThreadsManager::wait_for_search_finished() {
+
+  Thread* main = threads[0];
+  lock_grab(main->sleepLock);
+  while (!main->do_sleep) cond_wait(sleepCond, main->sleepLock);
+  lock_release(main->sleepLock);
+}
+
+
+// ThreadsManager::start_searching() is used by UI thread to wake up the main
+// thread parked in main_loop() and starting a new search. If async 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.front();
-
-  lock_grab(main.sleepLock);
+void ThreadsManager::start_searching(const Position& pos, const LimitsType& limits,
+                                     const std::set<Move>& searchMoves, bool async) {
+  wait_for_search_finished();
 
-  // Wait main thread has finished before to launch a new search
-  while (!main.do_sleep)
-      cond_wait(sleepCond, main.sleepLock);
+  Signals.stopOnPonderhit = Signals.firstRootMove = false;
+  Signals.stop = Signals.failedLowAtRoot = false;
 
-  // 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
+  threads[0]->wake_up(); // Start main thread
 
   if (!async)
-      while (!main.do_sleep)
-          cond_wait(sleepCond, main.sleepLock);
-
-  lock_release(main.sleepLock);
-}
-
-
-// ThreadsManager::stop_thinking() is used by UI thread to raise a stop request
-// and to wait for the main thread finishing the search. Needed to wait exiting
-// and terminate the threads after a 'quit' command.
-
-void ThreadsManager::stop_thinking() {
-
-  Thread& main = *threads.front();
-
-  Search::Signals.stop = true;
-
-  lock_grab(main.sleepLock);
-
-  cond_signal(main.sleepCond); // In case is waiting for stop or ponderhit
-
-  while (!main.do_sleep)
-      cond_wait(sleepCond, main.sleepLock);
-
-  lock_release(main.sleepLock);
+      wait_for_search_finished();
 }