X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fthread.cpp;h=440b8bf0e4f06b5ea6087aa76c2e9aec3ca02cc0;hp=34424d3791c7b30fdabab421b93c506c93f285a0;hb=8de29390f2d2bd31585b93ff46eae3051126f666;hpb=86f04dbcc08e52864c1136d713996e3a0c8d2610

diff --git a/src/thread.cpp b/src/thread.cpp
index 34424d37..440b8bf0 100644
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -2,6 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
+  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -29,92 +30,69 @@ using namespace Search;
 
 ThreadPool Threads; // Global object
 
-namespace {
+/// Thread constructor launches the thread and then waits until it goes to sleep
+/// in idle_loop().
 
- // Helpers to launch a thread after creation and joining before delete. Outside the
- // Thread constructor and destructor 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() {
-   std::thread* th = new T;
-   *th = std::thread(&T::idle_loop, (T*)th); // Will go to sleep
-   return (T*)th;
- }
-
- void delete_thread(ThreadBase* th) {
-
-   th->mutex.lock();
-   th->exit = true; // Search must be already finished
-   th->mutex.unlock();
+Thread::Thread() {
 
-   th->notify_one();
-   th->join(); // Wait for thread termination
-   delete th;
- }
+  resetCalls = exit = false;
+  maxPly = callsCnt = 0;
+  history.clear();
+  counterMoves.clear();
+  idx = Threads.size(); // Start from 0
 
+  std::unique_lock<Mutex> lk(mutex);
+  searching = true;
+  nativeThread = std::thread(&Thread::idle_loop, this);
+  sleepCondition.wait(lk, [&]{ return !searching; });
 }
 
 
-// ThreadBase::notify_one() wakes up the thread when there is some work to do
+/// Thread destructor waits for thread termination before returning
 
-void ThreadBase::notify_one() {
+Thread::~Thread() {
 
-  std::unique_lock<Mutex> lk(mutex);
+  mutex.lock();
+  exit = true;
   sleepCondition.notify_one();
+  mutex.unlock();
+  nativeThread.join();
 }
 
 
-// ThreadBase::wait() set the thread to sleep until 'condition' turns true
+/// Thread::wait_for_search_finished() waits on sleep condition
+/// until not searching
 
-void ThreadBase::wait(std::atomic<bool>& condition) {
+void Thread::wait_for_search_finished() {
 
   std::unique_lock<Mutex> lk(mutex);
-  sleepCondition.wait(lk, [&]{ return bool(condition); });
+  sleepCondition.wait(lk, [&]{ return !searching; });
 }
 
 
-// ThreadBase::wait_while() set the thread to sleep until 'condition' turns false
-void ThreadBase::wait_while(std::atomic<bool>& condition) {
-
-  std::unique_lock<Mutex> lk(mutex);
-  sleepCondition.wait(lk, [&]{ return !condition; });
-}
+/// Thread::wait() waits on sleep condition until condition is true
 
+void Thread::wait(std::atomic_bool& condition) {
 
-// Thread constructor makes some init but does not launch any execution thread,
-// which will be started only when the constructor returns.
-
-Thread::Thread() {
-
-  searching = false;
-  maxPly = 0;
-  history.clear();
-  counterMoves.clear();
-  idx = Threads.size(); // Starts from 0
+  std::unique_lock<Mutex> lk(mutex);
+  sleepCondition.wait(lk, [&]{ return bool(condition); });
 }
 
 
-// TimerThread::idle_loop() is where the timer thread waits Resolution milliseconds
-// and then calls check_time(). When not searching, thread sleeps until it's woken up.
+/// Thread::start_searching() wakes up the thread that will start the search
 
-void TimerThread::idle_loop() {
-
-  while (!exit)
-  {
-      std::unique_lock<Mutex> lk(mutex);
+void Thread::start_searching(bool resume) {
 
-      if (!exit)
-          sleepCondition.wait_for(lk, std::chrono::milliseconds(run ? Resolution : INT_MAX));
+  std::unique_lock<Mutex> lk(mutex);
 
-      lk.unlock();
+  if (!resume)
+      searching = true;
 
-      if (!exit && run)
-          check_time();
-  }
+  sleepCondition.notify_one();
 }
 
 
-// Thread::idle_loop() is where the thread is parked when it has no work to do
+/// Thread::idle_loop() is where the thread is parked when it has no work to do
 
 void Thread::idle_loop() {
 
@@ -122,122 +100,83 @@ void Thread::idle_loop() {
   {
       std::unique_lock<Mutex> lk(mutex);
 
-      while (!searching && !exit)
-          sleepCondition.wait(lk);
+      searching = false;
 
-      lk.unlock();
-
-      if (!exit && searching)
-          search();
-  }
-}
-
-
-// MainThread::idle_loop() is where the main thread is parked waiting to be started
-// when there is a new search. The main thread will launch all the slave threads.
-
-void MainThread::idle_loop() {
-
-  while (!exit)
-  {
-      std::unique_lock<Mutex> lk(mutex);
-
-      thinking = false;
-
-      while (!thinking && !exit)
+      while (!searching && !exit)
       {
-          sleepCondition.notify_one(); // Wake up the UI thread if needed
+          sleepCondition.notify_one(); // Wake up any waiting thread
           sleepCondition.wait(lk);
       }
 
       lk.unlock();
 
       if (!exit)
-          think();
+          search();
   }
 }
 
 
-// MainThread::join() waits for main thread to finish thinking
-
-void MainThread::join() {
-
-  std::unique_lock<Mutex> lk(mutex);
-  sleepCondition.wait(lk, [&]{ return !thinking; });
-}
-
-
-// ThreadPool::init() is called at startup to create and launch requested threads,
-// that will go immediately to sleep. We cannot use a constructor because Threads
-// is a static object and we need a fully initialized engine at this point due to
-// allocation of Endgames in the Thread constructor.
+/// ThreadPool::init() creates and launches requested threads that will go
+/// immediately to sleep. We cannot use a constructor because Threads is a
+/// static object and we need a fully initialized engine at this point due to
+/// allocation of Endgames in the Thread constructor.
 
 void ThreadPool::init() {
 
-  timer = new_thread<TimerThread>();
-  push_back(new_thread<MainThread>());
+  push_back(new MainThread);
   read_uci_options();
 }
 
 
-// ThreadPool::exit() terminates the threads before the program exits. Cannot be
-// done in destructor because threads must be terminated before freeing us.
+/// ThreadPool::exit() terminates threads before the program exits. Cannot be
+/// done in destructor because threads must be terminated before deleting any
+/// static objects while still in main().
 
 void ThreadPool::exit() {
 
-  delete_thread(timer); // As first because check_time() accesses threads data
-  timer = nullptr;
-
-  for (Thread* th : *this)
-      delete_thread(th);
-
-  clear(); // Get rid of stale pointers
+  while (size())
+      delete back(), pop_back();
 }
 
 
-// ThreadPool::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 all possible
-// threads in advance (which include pawns and material tables), even if only a
-// few are to be used.
+/// ThreadPool::read_uci_options() updates internal threads parameters from the
+/// corresponding UCI options and creates/destroys threads to match requested
+/// number. Thread objects are dynamically allocated.
 
 void ThreadPool::read_uci_options() {
 
-  size_t requested  = Options["Threads"];
+  size_t requested = Options["Threads"];
 
   assert(requested > 0);
 
   while (size() < requested)
-      push_back(new_thread<Thread>());
+      push_back(new Thread);
 
   while (size() > requested)
-  {
-      delete_thread(back());
-      pop_back();
-  }
+      delete back(), pop_back();
 }
 
 
-// ThreadPool::nodes_searched() returns the number of nodes searched
+/// ThreadPool::nodes_searched() returns the number of nodes searched
 
 int64_t ThreadPool::nodes_searched() {
 
   int64_t nodes = 0;
-  for (Thread *th : *this)
+  for (Thread* th : *this)
       nodes += th->rootPos.nodes_searched();
   return nodes;
 }
 
 
-// ThreadPool::start_thinking() wakes up the main thread sleeping in
-// MainThread::idle_loop() and starts a new search, then returns immediately.
+/// ThreadPool::start_thinking() wakes up the main thread sleeping in idle_loop()
+/// and starts a new search, then returns immediately.
 
 void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits,
                                 StateStackPtr& states) {
-  main()->join();
 
-  Signals.stopOnPonderhit = Signals.firstRootMove = false;
-  Signals.stop = Signals.failedLowAtRoot = false;
+  main()->wait_for_search_finished();
+
+  Signals.stopOnPonderhit = Signals.stop = false;
 
   main()->rootMoves.clear();
   main()->rootPos = pos;
@@ -253,6 +192,5 @@ void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits,
           || std::count(limits.searchmoves.begin(), limits.searchmoves.end(), m))
           main()->rootMoves.push_back(RootMove(m));
 
-  main()->thinking = true;
-  main()->notify_one(); // Wake up main thread: 'thinking' must be already set
+  main()->start_searching();
 }