X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fthread.cpp;h=786258a2ed564961fdb75f67024944aaf8c25d49;hp=ff52576b062785c49f8eae6bfa360b0380dbae71;hb=856a5f3aaaf8b9d53599963decacd4476b55c034;hpb=6fa6da3ee13d2b7bdbec3cd24ff8ca43233c74fb

diff --git a/src/thread.cpp b/src/thread.cpp
index ff52576b..786258a2 100644
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -33,13 +33,19 @@ extern void check_time();
 
 namespace {
 
+ // start_routine() is the C function which is called when a new thread
+ // is launched. It is a wrapper to the virtual function idle_loop().
+
+ extern "C" { long start_routine(ThreadBase* th) { th->idle_loop(); return 0; } }
+
+
  // 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
  // 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
+   thread_create(th->handle, start_routine, th); // Will go to sleep
    return th;
  }
 
@@ -50,7 +56,7 @@ namespace {
    th->mutex.unlock();
 
    th->notify_one();
-   th->nativeThread.join(); // Wait for thread termination
+   thread_join(th->handle); // Wait for thread termination
    delete th;
  }
 
@@ -61,8 +67,9 @@ namespace {
 
 void ThreadBase::notify_one() {
 
-  std::unique_lock<std::mutex>(this->mutex);
+  mutex.lock();
   sleepCondition.notify_one();
+  mutex.unlock();
 }
 
 
@@ -70,8 +77,9 @@ void ThreadBase::notify_one() {
 
 void ThreadBase::wait_for(volatile const bool& condition) {
 
-  std::unique_lock<std::mutex> lk(mutex);
-  sleepCondition.wait(lk, [&]{ return condition; });
+  mutex.lock();
+  while (!condition) sleepCondition.wait(mutex);
+  mutex.unlock();
 }
 
 
@@ -83,8 +91,8 @@ Thread::Thread() /* : splitPoints() */ { // Initialization of non POD broken in
   searching = false;
   maxPly = 0;
   splitPointsSize = 0;
-  activeSplitPoint = nullptr;
-  activePosition = nullptr;
+  activeSplitPoint = NULL;
+  activePosition = NULL;
   idx = Threads.size(); // Starts from 0
 }
 
@@ -102,13 +110,14 @@ bool Thread::cutoff_occurred() const {
 }
 
 
-// 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).
+// Thread::available_to() checks whether the thread is available to help the
+// thread '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 split point, it is only available as a slave to the slaves
+// 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::can_join(const SplitPoint* sp) const {
+bool Thread::available_to(const Thread* master) const {
 
   if (searching)
       return false;
@@ -119,7 +128,7 @@ bool Thread::can_join(const SplitPoint* sp) const {
 
   // 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);
+  return !size || splitPoints[size - 1].slavesMask.test(master->idx);
 }
 
 
@@ -164,21 +173,21 @@ void Thread::split(Position& pos, Stack* ss, Value alpha, Value beta, Value* bes
   // Try to allocate available threads and ask them to start searching setting
   // 'searching' flag. This must be done under lock protection to avoid concurrent
   // allocation of the same slave by another master.
-  Threads.spinlock.acquire();
-  sp.spinlock.acquire();
+  Threads.mutex.lock();
+  sp.mutex.lock();
 
   sp.allSlavesSearching = true; // Must be set under lock protection
   ++splitPointsSize;
   activeSplitPoint = &sp;
-  activePosition = nullptr;
+  activePosition = NULL;
 
   Thread* slave;
 
   while (    sp.slavesMask.count() < MAX_SLAVES_PER_SPLITPOINT
-         && (slave = Threads.available_slave(activeSplitPoint)) != nullptr)
+         && (slave = Threads.available_slave(this)) != NULL)
   {
       sp.slavesMask.set(slave->idx);
-      slave->activeSplitPoint = activeSplitPoint;
+      slave->activeSplitPoint = &sp;
       slave->searching = true; // Slave leaves idle_loop()
       slave->notify_one(); // Could be sleeping
   }
@@ -187,8 +196,8 @@ void Thread::split(Position& pos, Stack* ss, Value alpha, Value beta, Value* bes
   // 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();
-  Threads.spinlock.release();
+  sp.mutex.unlock();
+  Threads.mutex.unlock();
 
   Thread::idle_loop(); // Force a call to base class idle_loop()
 
@@ -201,8 +210,8 @@ void Thread::split(Position& pos, Stack* ss, Value alpha, Value beta, Value* bes
   // We have returned from the idle loop, which means that all threads are
   // finished. Note that setting 'searching' and decreasing splitPointsSize must
   // be done under lock protection to avoid a race with Thread::available_to().
-  Threads.spinlock.acquire();
-  sp.spinlock.acquire();
+  Threads.mutex.lock();
+  sp.mutex.lock();
 
   searching = true;
   --splitPointsSize;
@@ -212,8 +221,8 @@ void Thread::split(Position& pos, Stack* ss, Value alpha, Value beta, Value* bes
   *bestMove = sp.bestMove;
   *bestValue = sp.bestValue;
 
-  sp.spinlock.release();
-  Threads.spinlock.release();
+  sp.mutex.unlock();
+  Threads.mutex.unlock();
 }
 
 
@@ -224,12 +233,12 @@ void TimerThread::idle_loop() {
 
   while (!exit)
   {
-      std::unique_lock<std::mutex> lk(mutex);
+      mutex.lock();
 
       if (!exit)
-          sleepCondition.wait_for(lk, std::chrono::milliseconds(run ? Resolution : INT_MAX));
+          sleepCondition.wait_for(mutex, run ? Resolution : INT_MAX);
 
-      lk.unlock();
+      mutex.unlock();
 
       if (run)
           check_time();
@@ -244,17 +253,17 @@ void MainThread::idle_loop() {
 
   while (!exit)
   {
-      std::unique_lock<std::mutex> lk(mutex);
+      mutex.lock();
 
       thinking = false;
 
       while (!thinking && !exit)
       {
           Threads.sleepCondition.notify_one(); // Wake up the UI thread if needed
-          sleepCondition.wait(lk);
+          sleepCondition.wait(mutex);
       }
 
-      lk.unlock();
+      mutex.unlock();
 
       if (!exit)
       {
@@ -290,8 +299,8 @@ void ThreadPool::exit() {
 
   delete_thread(timer); // As first because check_time() accesses threads data
 
-  for (Thread* th : *this)
-      delete_thread(th);
+  for (iterator it = begin(); it != end(); ++it)
+      delete_thread(*it);
 }
 
 
@@ -324,15 +333,15 @@ void ThreadPool::read_uci_options() {
 
 
 // ThreadPool::available_slave() tries to find an idle thread which is available
-// to join SplitPoint 'sp'.
+// as a slave for the thread 'master'.
 
-Thread* ThreadPool::available_slave(const SplitPoint* sp) const {
+Thread* ThreadPool::available_slave(const Thread* master) const {
 
-  for (Thread* th : *this)
-      if (th->can_join(sp))
-          return th;
+  for (const_iterator it = begin(); it != end(); ++it)
+      if ((*it)->available_to(master))
+          return *it;
 
-  return nullptr;
+  return NULL;
 }
 
 
@@ -340,8 +349,10 @@ Thread* ThreadPool::available_slave(const SplitPoint* sp) const {
 
 void ThreadPool::wait_for_think_finished() {
 
-  std::unique_lock<std::mutex> lk(main()->mutex);
-  sleepCondition.wait(lk, [&]{ return !main()->thinking; });
+  MainThread* th = main();
+  th->mutex.lock();
+  while (th->thinking) sleepCondition.wait(th->mutex);
+  th->mutex.unlock();
 }
 
 
@@ -352,7 +363,7 @@ void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits,
                                 StateStackPtr& states) {
   wait_for_think_finished();
 
-  SearchTime = now(); // As early as possible
+  SearchTime = Time::now(); // As early as possible
 
   Signals.stopOnPonderhit = Signals.firstRootMove = false;
   Signals.stop = Signals.failedLowAtRoot = false;
@@ -362,14 +373,14 @@ void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits,
   Limits = limits;
   if (states.get()) // If we don't set a new position, preserve current state
   {
-      SetupStates = std::move(states); // Ownership transfer here
+      SetupStates = states; // Ownership transfer here
       assert(!states.get());
   }
 
-  for (const auto& m : MoveList<LEGAL>(pos))
+  for (MoveList<LEGAL> it(pos); *it; ++it)
       if (   limits.searchmoves.empty()
-          || std::count(limits.searchmoves.begin(), limits.searchmoves.end(), m))
-          RootMoves.push_back(RootMove(m));
+          || std::count(limits.searchmoves.begin(), limits.searchmoves.end(), *it))
+          RootMoves.push_back(RootMove(*it));
 
   main()->thinking = true;
   main()->notify_one(); // Starts main thread