X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fthread.cpp;h=1336ce077cdeac25abb6fc2811221db3aee1dc38;hp=c9cce8d0c6c2240aea7b92234062d68c7361e63b;hb=588670e8d2ed5735300c5549ef754ceb09f1f461;hpb=1b6b711c444362d442f8362d356f668f676ec5cb diff --git a/src/thread.cpp b/src/thread.cpp index c9cce8d0..1336ce07 100644 --- a/src/thread.cpp +++ b/src/thread.cpp @@ -32,26 +32,23 @@ 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. + // is launched. It is a wrapper to the virtual function idle_loop(). - long start_routine(Thread* th) { (th->*(th->start_fn))(); return 0; } + long start_routine(Thread* th) { th->idle_loop(); 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. +// the the virtual function idle_loop(), going immediately to sleep. -Thread::Thread(Fn fn) : splitPoints() { +Thread::Thread() : splitPoints() { - is_searching = do_exit = false; + searching = exit = false; maxPly = splitPointsCnt = 0; curSplitPoint = NULL; - start_fn = fn; idx = Threads.size(); - do_sleep = (fn != &Thread::main_loop); // Avoid a race with start_searching() - if (!thread_create(handle, start_routine, this)) { std::cerr << "Failed to create thread number " << idx << std::endl; @@ -60,47 +57,49 @@ Thread::Thread(Fn fn) : splitPoints() { } -// Thread d'tor waits for thread termination before to return. +// Thread d'tor waits for thread termination before to return Thread::~Thread() { - assert(do_sleep); - - do_exit = true; // Search must be already finished - wake_up(); + exit = true; // Search must be already finished + notify_one(); thread_join(handle); // Wait for thread termination } -// Thread::timer_loop() is where the timer thread waits maxPly milliseconds and -// then calls check_time(). If maxPly is 0 thread sleeps until is woken up. +// TimerThread::idle_loop() is where the timer thread waits msec milliseconds +// and then calls check_time(). If msec is 0 thread sleeps until is woken up. extern void check_time(); -void Thread::timer_loop() { +void TimerThread::idle_loop() { - while (!do_exit) + while (!exit) { mutex.lock(); - sleepCondition.wait_for(mutex, maxPly ? maxPly : INT_MAX); + + if (!exit) + sleepCondition.wait_for(mutex, msec ? msec : INT_MAX); + mutex.unlock(); - check_time(); + + if (msec) + check_time(); } } -// Thread::main_loop() is where the main thread is parked waiting to be started +// MainThread::idle_loop() is where the main thread is parked waiting to be started // when there is a new search. Main thread will launch all the slave threads. -void Thread::main_loop() { +void MainThread::idle_loop() { while (true) { mutex.lock(); - do_sleep = true; // Always return to sleep after a search - is_searching = false; + thinking = false; - while (do_sleep && !do_exit) + while (!thinking && !exit) { Threads.sleepCondition.notify_one(); // Wake up UI thread if needed sleepCondition.wait(mutex); @@ -108,22 +107,23 @@ void Thread::main_loop() { mutex.unlock(); - if (do_exit) + if (exit) return; - is_searching = true; + searching = true; Search::think(); - assert(is_searching); + assert(searching); + + searching = false; } } -// 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 when there is some search to do -void Thread::wake_up() { +void Thread::notify_one() { mutex.lock(); sleepCondition.notify_one(); @@ -131,19 +131,12 @@ void Thread::wake_up() { } -// 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 -// then return, after which the bestmove and pondermove will be printed. - -void Thread::wait_for_stop_or_ponderhit() { +// Thread::wait_for() set the thread to sleep until condition 'b' turns true - Signals.stopOnPonderhit = true; +void Thread::wait_for(volatile const bool& b) { mutex.lock(); - while (!Signals.stop) sleepCondition.wait(mutex);; + while (!b) sleepCondition.wait(mutex); mutex.unlock(); } @@ -170,7 +163,7 @@ bool Thread::cutoff_occurred() const { bool Thread::is_available_to(Thread* master) const { - if (is_searching) + if (searching) return false; // Make a local copy to be sure doesn't become zero under our feet while @@ -190,8 +183,9 @@ bool Thread::is_available_to(Thread* master) const { void ThreadPool::init() { - timer = new Thread(&Thread::timer_loop); - threads.push_back(new Thread(&Thread::main_loop)); + sleepWhileIdle = true; + timer = new TimerThread(); + threads.push_back(new MainThread()); read_uci_options(); } @@ -216,13 +210,12 @@ void ThreadPool::read_uci_options() { maxThreadsPerSplitPoint = Options["Max Threads per Split Point"]; minimumSplitDepth = Options["Min Split Depth"] * ONE_PLY; - useSleepingThreads = Options["Use Sleeping Threads"]; size_t requested = Options["Threads"]; assert(requested > 0); while (threads.size() < requested) - threads.push_back(new Thread(&Thread::idle_loop)); + threads.push_back(new Thread()); while (threads.size() > requested) { @@ -232,34 +225,6 @@ void ThreadPool::read_uci_options() { } -// wake_up() is called before a new search to start the threads that are waiting -// on the sleep condition and to reset maxPly. When useSleepingThreads is set -// threads will be woken up at split time. - -void ThreadPool::wake_up() const { - - for (size_t i = 0; i < threads.size(); i++) - { - threads[i]->maxPly = 0; - threads[i]->do_sleep = false; - - if (!useSleepingThreads) - threads[i]->wake_up(); - } -} - - -// sleep() is called after the search finishes to ask all the threads but the -// main one to go waiting on a sleep condition. - -void ThreadPool::sleep() const { - - // 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'. @@ -319,7 +284,7 @@ Value ThreadPool::split(Position& pos, Stack* ss, Value alpha, Value beta, sp.nodes = 0; sp.ss = ss; - assert(master->is_searching); + assert(master->searching); master->curSplitPoint = &sp; int slavesCnt = 0; @@ -335,10 +300,8 @@ Value ThreadPool::split(Position& pos, Stack* ss, Value alpha, Value beta, { 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]->searching = true; // Slave leaves idle_loop() + threads[i]->notify_one(); // Could be sleeping if (++slavesCnt + 1 >= maxThreadsPerSplitPoint) // Master is always included break; @@ -355,11 +318,11 @@ Value ThreadPool::split(Position& pos, Stack* ss, Value alpha, Value beta, // their work at this split point. if (slavesCnt || Fake) { - master->idle_loop(); + master->Thread::idle_loop(); // Force a call to base class 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. - assert(!master->is_searching); + assert(!master->searching); } // We have returned from the idle loop, which means that all threads are @@ -368,7 +331,7 @@ Value ThreadPool::split(Position& pos, Stack* ss, Value alpha, Value beta, mutex.lock(); sp.mutex.lock(); - master->is_searching = true; + master->searching = true; master->splitPointsCnt--; master->curSplitPoint = sp.parent; pos.set_nodes_searched(pos.nodes_searched() + sp.nodes); @@ -385,44 +348,30 @@ template Value ThreadPool::split(Position&, Stack*, Value, Value, Value, template Value ThreadPool::split(Position&, Stack*, Value, Value, Value, Move*, Depth, Move, int, MovePicker&, int); -// 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->mutex.lock(); - timer->maxPly = msec; - timer->sleepCondition.notify_one(); // Wake up and restart the timer - timer->mutex.unlock(); -} - - -// wait_for_search_finished() waits for main thread to go to sleep, this means -// search is finished. Then returns. +// wait_for_think_finished() waits for main thread to go to sleep then returns -void ThreadPool::wait_for_search_finished() { +void ThreadPool::wait_for_think_finished() { - Thread* t = main_thread(); + MainThread* t = main_thread(); t->mutex.lock(); - t->sleepCondition.notify_one(); // In case is waiting for stop or ponderhit - while (!t->do_sleep) sleepCondition.wait(t->mutex); + while (t->thinking) sleepCondition.wait(t->mutex); t->mutex.unlock(); } -// start_searching() wakes up the main thread sleeping in main_loop() so to start +// start_thinking() wakes up the main thread sleeping in main_loop() so to start // a new search, then returns immediately. -void ThreadPool::start_searching(const Position& pos, const LimitsType& limits, - const std::vector& searchMoves, StateStackPtr& states) { - wait_for_search_finished(); +void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits, + const std::vector& searchMoves, StateStackPtr& states) { + wait_for_think_finished(); 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(); @@ -431,6 +380,6 @@ void ThreadPool::start_searching(const Position& pos, const LimitsType& limits, 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()->thinking = true; + main_thread()->notify_one(); // Starts main thread }