X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fthread.cpp;h=ff52576b062785c49f8eae6bfa360b0380dbae71;hp=5c013c6a0b72e06830d2a7389706f45d73b9a43a;hb=e53774bc49dd0aaa1c129ee98c09e1a56ef974fb;hpb=dccaa145d2b57999aa3e368c7c9203731b4e9685

diff --git a/src/thread.cpp b/src/thread.cpp
index 5c013c6a..ff52576b 100644
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -33,19 +33,13 @@ 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();
-   thread_create(th->handle, start_routine, th); // Will go to sleep
+   th->nativeThread = std::thread(&ThreadBase::idle_loop, th); // Will go to sleep
    return th;
  }
 
@@ -56,7 +50,7 @@ namespace {
    th->mutex.unlock();
 
    th->notify_one();
-   thread_join(th->handle); // Wait for thread termination
+   th->nativeThread.join(); // Wait for thread termination
    delete th;
  }
 
@@ -67,9 +61,8 @@ namespace {
 
 void ThreadBase::notify_one() {
 
-  mutex.lock();
+  std::unique_lock<std::mutex>(this->mutex);
   sleepCondition.notify_one();
-  mutex.unlock();
 }
 
 
@@ -77,9 +70,8 @@ void ThreadBase::notify_one() {
 
 void ThreadBase::wait_for(volatile const bool& condition) {
 
-  mutex.lock();
-  while (!condition) sleepCondition.wait(mutex);
-  mutex.unlock();
+  std::unique_lock<std::mutex> lk(mutex);
+  sleepCondition.wait(lk, [&]{ return condition; });
 }
 
 
@@ -89,9 +81,10 @@ void ThreadBase::wait_for(volatile const bool& condition) {
 Thread::Thread() /* : splitPoints() */ { // Initialization of non POD broken in MSVC
 
   searching = false;
-  maxPly = splitPointsSize = 0;
-  activeSplitPoint = NULL;
-  activePosition = NULL;
+  maxPly = 0;
+  splitPointsSize = 0;
+  activeSplitPoint = nullptr;
+  activePosition = nullptr;
   idx = Threads.size(); // Starts from 0
 }
 
@@ -109,25 +102,24 @@ bool Thread::cutoff_occurred() const {
 }
 
 
-// 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).
+// 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::available_to(const Thread* master) const {
+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 int size = splitPointsSize;
+  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(master->idx);
+  return !size || splitPoints[size - 1].slavesMask.test(sp->master->idx);
 }
 
 
@@ -152,10 +144,9 @@ void Thread::split(Position& pos, Stack* ss, Value alpha, Value beta, Value* bes
   // Pick and init the next available split point
   SplitPoint& sp = splitPoints[splitPointsSize];
 
-  sp.masterThread = this;
+  sp.master = this;
   sp.parentSplitPoint = activeSplitPoint;
   sp.slavesMask = 0, sp.slavesMask.set(idx);
-  sp.slavesCount = 1;
   sp.depth = depth;
   sp.bestValue = *bestValue;
   sp.bestMove = *bestMove;
@@ -173,22 +164,21 @@ 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.mutex.lock();
-  sp.mutex.lock();
+  Threads.spinlock.acquire();
+  sp.spinlock.acquire();
 
   sp.allSlavesSearching = true; // Must be set under lock protection
   ++splitPointsSize;
   activeSplitPoint = &sp;
-  activePosition = NULL;
+  activePosition = nullptr;
 
   Thread* slave;
 
-  while (    sp.slavesCount < MAX_SLAVES_PER_SPLITPOINT
-         && (slave = Threads.available_slave(this)) != NULL)
+  while (    sp.slavesMask.count() < MAX_SLAVES_PER_SPLITPOINT
+         && (slave = Threads.available_slave(activeSplitPoint)) != nullptr)
   {
       sp.slavesMask.set(slave->idx);
-      sp.slavesCount++;
-      slave->activeSplitPoint = &sp;
+      slave->activeSplitPoint = activeSplitPoint;
       slave->searching = true; // Slave leaves idle_loop()
       slave->notify_one(); // Could be sleeping
   }
@@ -197,8 +187,8 @@ 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.mutex.unlock();
-  Threads.mutex.unlock();
+  sp.spinlock.release();
+  Threads.spinlock.release();
 
   Thread::idle_loop(); // Force a call to base class idle_loop()
 
@@ -211,8 +201,8 @@ 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.mutex.lock();
-  sp.mutex.lock();
+  Threads.spinlock.acquire();
+  sp.spinlock.acquire();
 
   searching = true;
   --splitPointsSize;
@@ -222,8 +212,8 @@ void Thread::split(Position& pos, Stack* ss, Value alpha, Value beta, Value* bes
   *bestMove = sp.bestMove;
   *bestValue = sp.bestValue;
 
-  sp.mutex.unlock();
-  Threads.mutex.unlock();
+  sp.spinlock.release();
+  Threads.spinlock.release();
 }
 
 
@@ -234,12 +224,12 @@ void TimerThread::idle_loop() {
 
   while (!exit)
   {
-      mutex.lock();
+      std::unique_lock<std::mutex> lk(mutex);
 
       if (!exit)
-          sleepCondition.wait_for(mutex, run ? Resolution : INT_MAX);
+          sleepCondition.wait_for(lk, std::chrono::milliseconds(run ? Resolution : INT_MAX));
 
-      mutex.unlock();
+      lk.unlock();
 
       if (run)
           check_time();
@@ -254,17 +244,17 @@ void MainThread::idle_loop() {
 
   while (!exit)
   {
-      mutex.lock();
+      std::unique_lock<std::mutex> lk(mutex);
 
       thinking = false;
 
       while (!thinking && !exit)
       {
           Threads.sleepCondition.notify_one(); // Wake up the UI thread if needed
-          sleepCondition.wait(mutex);
+          sleepCondition.wait(lk);
       }
 
-      mutex.unlock();
+      lk.unlock();
 
       if (!exit)
       {
@@ -300,8 +290,8 @@ void ThreadPool::exit() {
 
   delete_thread(timer); // As first because check_time() accesses threads data
 
-  for (iterator it = begin(); it != end(); ++it)
-      delete_thread(*it);
+  for (Thread* th : *this)
+      delete_thread(th);
 }
 
 
@@ -334,15 +324,15 @@ void ThreadPool::read_uci_options() {
 
 
 // ThreadPool::available_slave() tries to find an idle thread which is available
-// as a slave for the thread 'master'.
+// to join SplitPoint 'sp'.
 
-Thread* ThreadPool::available_slave(const Thread* master) const {
+Thread* ThreadPool::available_slave(const SplitPoint* sp) const {
 
-  for (const_iterator it = begin(); it != end(); ++it)
-      if ((*it)->available_to(master))
-          return *it;
+  for (Thread* th : *this)
+      if (th->can_join(sp))
+          return th;
 
-  return NULL;
+  return nullptr;
 }
 
 
@@ -350,10 +340,8 @@ Thread* ThreadPool::available_slave(const Thread* master) const {
 
 void ThreadPool::wait_for_think_finished() {
 
-  MainThread* th = main();
-  th->mutex.lock();
-  while (th->thinking) sleepCondition.wait(th->mutex);
-  th->mutex.unlock();
+  std::unique_lock<std::mutex> lk(main()->mutex);
+  sleepCondition.wait(lk, [&]{ return !main()->thinking; });
 }
 
 
@@ -364,7 +352,7 @@ void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits,
                                 StateStackPtr& states) {
   wait_for_think_finished();
 
-  SearchTime = Time::now(); // As early as possible
+  SearchTime = now(); // As early as possible
 
   Signals.stopOnPonderhit = Signals.firstRootMove = false;
   Signals.stop = Signals.failedLowAtRoot = false;
@@ -374,14 +362,14 @@ 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 = states; // Ownership transfer here
+      SetupStates = std::move(states); // Ownership transfer here
       assert(!states.get());
   }
 
-  for (MoveList<LEGAL> it(pos); *it; ++it)
+  for (const auto& m : MoveList<LEGAL>(pos))
       if (   limits.searchmoves.empty()
-          || std::count(limits.searchmoves.begin(), limits.searchmoves.end(), *it))
-          RootMoves.push_back(RootMove(*it));
+          || std::count(limits.searchmoves.begin(), limits.searchmoves.end(), m))
+          RootMoves.push_back(RootMove(m));
 
   main()->thinking = true;
   main()->notify_one(); // Starts main thread