X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fthread.cpp;h=b11447dfc175f41180fc3d2a265c215ad79b8372;hp=7b9a4f327823a4e0e60bcf9492d972ea0ccaa16d;hb=81cd7d787ef2b9d914c9c09ddbed59dffb78ec77;hpb=b1f57e92cea7bd36126ef8c26928d8991b74baef diff --git a/src/thread.cpp b/src/thread.cpp index 7b9a4f32..b11447df 100644 --- a/src/thread.cpp +++ b/src/thread.cpp @@ -27,27 +27,22 @@ using namespace Search; -ThreadsManager Threads; // Global object -THREAD_LOCAL Thread* this_thread; // Thread local variable +ThreadPool 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. - long start_routine(Thread* th) { - - this_thread = th; // Save pointer into thread local storage - (th->*(th->start_fn))(); - return 0; - } + long start_routine(Thread* th) { (th->*(th->start_fn))(); return 0; } } } + // Thread c'tor starts a newly-created thread of execution that will call // the idle loop function pointed by start_fn going immediately to sleep. -Thread::Thread(Fn fn) { +Thread::Thread(Fn fn) : splitPoints() { is_searching = do_exit = false; maxPly = splitPointsCnt = 0; @@ -57,12 +52,6 @@ Thread::Thread(Fn fn) { do_sleep = (fn != &Thread::main_loop); // Avoid a race with start_searching() - lock_init(sleepLock); - cond_init(sleepCond); - - for (int j = 0; j < MAX_SPLITPOINTS_PER_THREAD; j++) - lock_init(splitPoints[j].lock); - if (!thread_create(handle, start_routine, this)) { std::cerr << "Failed to create thread number " << idx << std::endl; @@ -78,15 +67,8 @@ Thread::~Thread() { assert(do_sleep); do_exit = true; // Search must be already finished - wake_up(); - + notify_one(); thread_join(handle); // Wait for thread termination - - lock_destroy(sleepLock); - cond_destroy(sleepCond); - - for (int j = 0; j < MAX_SPLITPOINTS_PER_THREAD; j++) - lock_destroy(splitPoints[j].lock); } @@ -98,9 +80,9 @@ void Thread::timer_loop() { while (!do_exit) { - lock_grab(sleepLock); - timed_wait(sleepCond, sleepLock, maxPly ? maxPly : INT_MAX); - lock_release(sleepLock); + mutex.lock(); + sleepCondition.wait_for(mutex, maxPly ? maxPly : INT_MAX); + mutex.unlock(); check_time(); } } @@ -113,18 +95,18 @@ void Thread::main_loop() { while (true) { - lock_grab(sleepLock); + mutex.lock(); do_sleep = true; // Always return to sleep after a search is_searching = false; while (do_sleep && !do_exit) { - cond_signal(Threads.sleepCond); // Wake up UI thread if needed - cond_wait(sleepCond, sleepLock); + Threads.sleepCondition.notify_one(); // Wake up UI thread if needed + sleepCondition.wait(mutex); } - lock_release(sleepLock); + mutex.unlock(); if (do_exit) return; @@ -132,35 +114,35 @@ void Thread::main_loop() { is_searching = true; Search::think(); + + assert(is_searching); } } -// Thread::wake_up() wakes up the thread, normally at the beginning of the search -// or, if "sleeping threads" is used at split time. +// Thread::notify_one() wakes up the thread, normally at the beginning of the +// search or, if "sleeping threads" is used at split time. -void Thread::wake_up() { +void Thread::notify_one() { - lock_grab(sleepLock); - cond_signal(sleepCond); - lock_release(sleepLock); + mutex.lock(); + sleepCondition.notify_one(); + mutex.unlock(); } -// Thread::wait_for_stop_or_ponderhit() is called when the maximum depth is -// reached while the program is pondering. The point is to work around a wrinkle -// in the UCI protocol: When pondering, the engine is not allowed to give a -// "bestmove" before the GUI sends it a "stop" or "ponderhit" command. We simply -// wait here until one of these commands (that raise StopRequest) is sent and +// Thread::wait_for_stop() is called when the maximum depth is reached while +// the program is pondering. The point is to work around a wrinkle in the UCI +// protocol: When pondering, the engine is not allowed to give a "bestmove" +// before the GUI sends it a "stop" or "ponderhit" command. We simply wait here +// until one of these commands (that raise Signals.stop) is sent and // then return, after which the bestmove and pondermove will be printed. -void Thread::wait_for_stop_or_ponderhit() { - - Signals.stopOnPonderhit = true; +void Thread::wait_for_stop() { - lock_grab(sleepLock); - while (!Signals.stop) cond_wait(sleepCond, sleepLock); - lock_release(sleepLock); + mutex.lock(); + while (!Signals.stop) sleepCondition.wait(mutex); + mutex.unlock(); } @@ -204,27 +186,22 @@ bool Thread::is_available_to(Thread* master) const { // 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() { +void ThreadPool::init() { - cond_init(sleepCond); - lock_init(splitLock); timer = new Thread(&Thread::timer_loop); threads.push_back(new Thread(&Thread::main_loop)); - this_thread = main_thread(); // Use main thread's resources read_uci_options(); } -// d'tor cleanly terminates the threads when the program exits. +// exit() cleanly terminates the threads before the program exits. -ThreadsManager::~ThreadsManager() { +void ThreadPool::exit() { - for (int i = 0; i < size(); i++) - delete threads[i]; + delete timer; // As first becuase check_time() accesses threads data - delete timer; - lock_destroy(splitLock); - cond_destroy(sleepCond); + for (size_t i = 0; i < threads.size(); i++) + delete threads[i]; } @@ -233,19 +210,19 @@ ThreadsManager::~ThreadsManager() { // objects are dynamically allocated to avoid creating in advance all possible // threads, with included pawns and material tables, if only few are used. -void ThreadsManager::read_uci_options() { +void ThreadPool::read_uci_options() { maxThreadsPerSplitPoint = Options["Max Threads per Split Point"]; minimumSplitDepth = Options["Min Split Depth"] * ONE_PLY; useSleepingThreads = Options["Use Sleeping Threads"]; - int requested = Options["Threads"]; + size_t requested = Options["Threads"]; assert(requested > 0); - while (size() < requested) + while (threads.size() < requested) threads.push_back(new Thread(&Thread::idle_loop)); - while (size() > requested) + while (threads.size() > requested) { delete threads.back(); threads.pop_back(); @@ -257,15 +234,15 @@ void ThreadsManager::read_uci_options() { // on the sleep condition and to reset maxPly. When useSleepingThreads is set // threads will be woken up at split time. -void ThreadsManager::wake_up() const { +void ThreadPool::wake_up() const { - for (int i = 0; i < size(); i++) + for (size_t i = 0; i < threads.size(); i++) { threads[i]->maxPly = 0; threads[i]->do_sleep = false; if (!useSleepingThreads) - threads[i]->wake_up(); + threads[i]->notify_one(); } } @@ -273,19 +250,20 @@ void ThreadsManager::wake_up() const { // 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() const { +void ThreadPool::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_searching() + // Main thread will go to sleep by itself to avoid a race with start_searching() + for (size_t i = 1; i < threads.size(); i++) + threads[i]->do_sleep = true; } // available_slave_exists() tries to find an idle thread which is available as // a slave for the thread 'master'. -bool ThreadsManager::available_slave_exists(Thread* master) const { +bool ThreadPool::available_slave_exists(Thread* master) const { - for (int i = 0; i < size(); i++) + for (size_t i = 0; i < threads.size(); i++) if (threads[i]->is_available_to(master)) return true; @@ -293,6 +271,16 @@ bool ThreadsManager::available_slave_exists(Thread* master) const { } +// set_timer() is used to set the timer to trigger after msec milliseconds. +// If msec is 0 then timer is stopped. + +void ThreadPool::set_timer(int msec) { + + timer->maxPly = msec; + timer->notify_one(); // Wake up and restart the timer +} + + // split() does the actual work of distributing the work at a node between // several available threads. If it does not succeed in splitting the node // (because no idle threads are available, or because we have no unused split @@ -303,9 +291,10 @@ bool ThreadsManager::available_slave_exists(Thread* master) const { // search(). When all threads have returned from search() then split() returns. template -Value ThreadsManager::split(Position& pos, Stack* ss, Value alpha, Value beta, - Value bestValue, Move* bestMove, Depth depth, - Move threatMove, int moveCount, MovePicker* mp, int nodeType) { +Value ThreadPool::split(Position& pos, Stack* ss, Value alpha, Value beta, + Value bestValue, Move* bestMove, Depth depth, Move threatMove, + int moveCount, MovePicker& mp, int nodeType) { + assert(pos.pos_is_ok()); assert(bestValue > -VALUE_INFINITE); assert(bestValue <= alpha); @@ -313,67 +302,68 @@ Value ThreadsManager::split(Position& pos, Stack* ss, Value alpha, Value beta, assert(beta <= VALUE_INFINITE); assert(depth > DEPTH_ZERO); - Thread* master = this_thread; + Thread* master = pos.this_thread(); if (master->splitPointsCnt >= MAX_SPLITPOINTS_PER_THREAD) return bestValue; // Pick the next available split point from the split point stack - SplitPoint* sp = &master->splitPoints[master->splitPointsCnt++]; - - sp->parent = master->curSplitPoint; - sp->master = master; - sp->cutoff = false; - sp->slavesMask = 1ULL << master->idx; - sp->depth = depth; - sp->bestMove = *bestMove; - sp->threatMove = threatMove; - sp->alpha = alpha; - sp->beta = beta; - sp->nodeType = nodeType; - sp->bestValue = bestValue; - sp->mp = mp; - sp->moveCount = moveCount; - sp->pos = &pos; - sp->nodes = 0; - sp->ss = ss; + SplitPoint& sp = master->splitPoints[master->splitPointsCnt]; + + sp.parent = master->curSplitPoint; + sp.master = master; + sp.cutoff = false; + sp.slavesMask = 1ULL << master->idx; + sp.depth = depth; + sp.bestMove = *bestMove; + sp.threatMove = threatMove; + sp.alpha = alpha; + sp.beta = beta; + sp.nodeType = nodeType; + sp.bestValue = bestValue; + sp.mp = ∓ + sp.moveCount = moveCount; + sp.pos = &pos; + sp.nodes = 0; + sp.ss = ss; assert(master->is_searching); - master->curSplitPoint = sp; + master->curSplitPoint = &sp; int slavesCnt = 0; // Try to allocate available threads and ask them to start searching setting // is_searching flag. This must be done under lock protection to avoid concurrent // allocation of the same slave by another master. - lock_grab(sp->lock); - lock_grab(splitLock); + mutex.lock(); + sp.mutex.lock(); - for (int i = 0; i < size() && !Fake; ++i) + for (size_t i = 0; i < threads.size() && !Fake; ++i) if (threads[i]->is_available_to(master)) { - sp->slavesMask |= 1ULL << i; - threads[i]->curSplitPoint = sp; + sp.slavesMask |= 1ULL << i; + threads[i]->curSplitPoint = &sp; threads[i]->is_searching = true; // Slave leaves idle_loop() if (useSleepingThreads) - threads[i]->wake_up(); + threads[i]->notify_one(); if (++slavesCnt + 1 >= maxThreadsPerSplitPoint) // Master is always included break; } - lock_release(splitLock); - lock_release(sp->lock); + master->splitPointsCnt++; + + sp.mutex.unlock(); + mutex.unlock(); // Everything is set up. The master thread enters the idle loop, from which // it will instantly launch a search, because its is_searching flag is set. - // We pass the split point as a parameter to the idle loop, which means that - // the thread will return from the idle loop when all slaves have finished + // The thread will return from the idle loop when all slaves have finished // their work at this split point. if (slavesCnt || Fake) { - master->idle_loop(sp); + master->idle_loop(); // In helpful master concept a master can help only a sub-tree of its split // point, and because here is all finished is not possible master is booked. @@ -383,71 +373,59 @@ Value ThreadsManager::split(Position& pos, Stack* ss, Value alpha, Value beta, // We have returned from the idle loop, which means that all threads are // finished. Note that setting is_searching and decreasing splitPointsCnt is // done under lock protection to avoid a race with Thread::is_available_to(). - lock_grab(sp->lock); // To protect sp->nodes - lock_grab(splitLock); + mutex.lock(); + sp.mutex.lock(); master->is_searching = true; master->splitPointsCnt--; - master->curSplitPoint = sp->parent; - pos.set_nodes_searched(pos.nodes_searched() + sp->nodes); - *bestMove = sp->bestMove; + master->curSplitPoint = sp.parent; + pos.set_nodes_searched(pos.nodes_searched() + sp.nodes); + *bestMove = sp.bestMove; - lock_release(splitLock); - lock_release(sp->lock); + sp.mutex.unlock(); + mutex.unlock(); - return sp->bestValue; + return sp.bestValue; } // Explicit template instantiations -template Value ThreadsManager::split(Position&, Stack*, Value, Value, Value, Move*, Depth, Move, int, MovePicker*, int); -template Value ThreadsManager::split(Position&, Stack*, Value, Value, Value, Move*, Depth, Move, int, MovePicker*, int); - - -// ThreadsManager::set_timer() is used to set the timer to trigger after msec -// milliseconds. If msec is 0 then timer is stopped. - -void ThreadsManager::set_timer(int msec) { - - lock_grab(timer->sleepLock); - timer->maxPly = msec; - cond_signal(timer->sleepCond); // Wake up and restart the timer - lock_release(timer->sleepLock); -} +template Value ThreadPool::split(Position&, Stack*, Value, Value, Value, Move*, Depth, Move, int, MovePicker&, int); +template Value ThreadPool::split(Position&, Stack*, Value, Value, Value, Move*, Depth, Move, int, MovePicker&, int); -// ThreadsManager::wait_for_search_finished() waits for main thread to go to -// sleep, this means search is finished. Then returns. +// 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() { +void ThreadPool::wait_for_search_finished() { Thread* t = main_thread(); - lock_grab(t->sleepLock); - cond_signal(t->sleepCond); // In case is waiting for stop or ponderhit - while (!t->do_sleep) cond_wait(sleepCond, t->sleepLock); - lock_release(t->sleepLock); + t->mutex.lock(); + while (!t->do_sleep) sleepCondition.wait(t->mutex); + t->mutex.unlock(); } -// ThreadsManager::start_searching() wakes up the main thread sleeping in -// main_loop() so to start a new search, then returns immediately. +// start_searching() wakes up the main thread sleeping in main_loop() so to start +// a new search, then returns immediately. -void ThreadsManager::start_searching(const Position& pos, const LimitsType& limits, - const std::vector& searchMoves) { +void ThreadPool::start_searching(const Position& pos, const LimitsType& limits, + const std::vector& searchMoves, StateStackPtr& states) { wait_for_search_finished(); - SearchTime.restart(); // As early as possible + SearchTime = Time::now(); // As early as possible Signals.stopOnPonderhit = Signals.firstRootMove = false; Signals.stop = Signals.failedLowAtRoot = false; - RootPosition = pos; + RootPos = pos; Limits = limits; + SetupStates = states; // Ownership transfer here RootMoves.clear(); - for (MoveList ml(pos); !ml.end(); ++ml) + for (MoveList ml(pos); !ml.end(); ++ml) if (searchMoves.empty() || count(searchMoves.begin(), searchMoves.end(), ml.move())) RootMoves.push_back(RootMove(ml.move())); main_thread()->do_sleep = false; - main_thread()->wake_up(); + main_thread()->notify_one(); }