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
#include "thread.h"
#include "uci.h"
-using namespace Search;
-
ThreadPool Threads; // Global object
-namespace {
-
- // 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;
- }
+/// Thread constructor launches the thread and then waits until it goes to sleep
+/// in idle_loop().
- 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); });
-}
-
-
-// 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; });
+ sleepCondition.wait(lk, [&]{ return !searching; });
}
-// Thread constructor makes some init but does not launch any execution thread,
-// which will be started only when the constructor returns.
+/// Thread::wait() waits on sleep condition until condition is true
-Thread::Thread() {
+void Thread::wait(std::atomic_bool& condition) {
- 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() {
+void Thread::start_searching(bool resume) {
- while (!exit)
- {
- std::unique_lock<Mutex> lk(mutex);
+ std::unique_lock<Mutex> lk(mutex);
- if (!exit)
- sleepCondition.wait_for(lk, std::chrono::milliseconds(run ? Resolution : INT_MAX));
+ if (!resume)
+ searching = true;
- lk.unlock();
-
- 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() {
{
std::unique_lock<Mutex> lk(mutex);
- while (!searching && !exit)
- sleepCondition.wait(lk);
-
- 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;
+ searching = 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();
+void ThreadPool::start_thinking(const Position& pos, StateListPtr& states,
+ const Search::LimitsType& limits) {
- Signals.stopOnPonderhit = Signals.firstRootMove = false;
- Signals.stop = Signals.failedLowAtRoot = false;
+ main()->wait_for_search_finished();
- main()->rootMoves.clear();
- main()->rootPos = pos;
- Limits = limits;
- if (states.get()) // If we don't set a new position, preserve current state
- {
- SetupStates = std::move(states); // Ownership transfer here
- assert(!states.get());
- }
+ Search::Signals.stopOnPonderhit = Search::Signals.stop = false;
+ Search::Limits = limits;
+ Search::RootMoves rootMoves;
for (const auto& m : MoveList<LEGAL>(pos))
if ( limits.searchmoves.empty()
|| std::count(limits.searchmoves.begin(), limits.searchmoves.end(), m))
- main()->rootMoves.push_back(RootMove(m));
+ rootMoves.push_back(Search::RootMove(m));
+
+ // After ownership transfer 'states' becomes empty, so if we stop the search
+ // and call 'go' again without setting a new position states.get() == NULL.
+ assert(states.get() || setupStates.get());
+
+ if (states.get())
+ setupStates = std::move(states); // Ownership transfer, states is now empty
+
+ StateInfo tmp = setupStates->back();
+
+ for (Thread* th : Threads)
+ {
+ th->maxPly = 0;
+ th->rootDepth = DEPTH_ZERO;
+ th->rootMoves = rootMoves;
+ th->rootPos.set(pos.fen(), pos.is_chess960(), &setupStates->back(), th);
+ }
+
+ setupStates->back() = tmp; // Restore st->previous, cleared by Position::set()
- main()->thinking = true;
- main()->notify_one(); // Wake up main thread: 'thinking' must be already set
+ main()->start_searching();
}
projects / stockfish / blobdiff