X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fthread.cpp;h=65d01d9100a874e19db9addea3772bafa735dd69;hp=1913aee43ca62601a68000392cad4e844c779fb0;hb=3aa471f2a9cb1cccd37c27906dd386b9724e32ab;hpb=f01b53c37400e676fdf13d52323bc7bb65502e90 diff --git a/src/thread.cpp b/src/thread.cpp index 1913aee4..65d01d91 100644 --- a/src/thread.cpp +++ b/src/thread.cpp @@ -32,29 +32,61 @@ ThreadsManager Threads; // Global object namespace { extern "C" { // start_routine() is the C function which is called when a new thread - // is launched. It simply calls idle_loop() of the supplied thread. The first - // and last thread are special. First one is the main search thread while the - // last one mimics a timer, they run in main_loop() and timer_loop(). + // is launched. It is a wrapper to member function pointed by start_fn. - long start_routine(Thread* th) { + long start_routine(Thread* th) { (th->*(th->start_fn))(); return 0; } - if (th->threadID == 0) - th->main_loop(); +} } + + +// 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) { + + is_searching = do_exit = false; + maxPly = splitPointsCnt = 0; + curSplitPoint = NULL; + start_fn = fn; + threadID = Threads.size(); - else if (th->threadID == MAX_THREADS) - th->timer_loop(); + do_sleep = (fn != &Thread::main_loop); // Avoid a race with start_searching() - else - th->idle_loop(NULL); + lock_init(sleepLock); + cond_init(sleepCond); + + for (int j = 0; j < MAX_SPLITPOINTS_PER_THREAD; j++) + lock_init(splitPoints[j].lock); - return 0; + if (!thread_create(handle, start_routine, this)) + { + std::cerr << "Failed to create thread number " << threadID << std::endl; + ::exit(EXIT_FAILURE); } +} -} } + +// 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(); + + 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); +} // Thread::timer_loop() is where the timer thread waits maxPly milliseconds and -// then calls do_timer_event(). If maxPly is 0 thread sleeps until is woken up. +// then calls check_time(). If maxPly is 0 thread sleeps until is woken up. extern void check_time(); void Thread::timer_loop() { @@ -100,11 +132,12 @@ void Thread::main_loop() { // Thread::wake_up() wakes up the thread, normally at the beginning of the search -// or, if "sleeping threads" is used, when there is some work to do. +// or, if "sleeping threads" is used at split time. void Thread::wake_up() { lock_grab(sleepLock); + do_sleep = false; cond_signal(sleepCond); lock_release(sleepLock); } @@ -122,16 +155,13 @@ void Thread::wait_for_stop_or_ponderhit() { Signals.stopOnPonderhit = true; lock_grab(sleepLock); - - while (!Signals.stop) - cond_wait(sleepCond, sleepLock); - + while (!Signals.stop) cond_wait(sleepCond, sleepLock); lock_release(sleepLock); } -// cutoff_occurred() checks whether a beta cutoff has occurred in the current -// active split point, or in some ancestor of the split point. +// Thread::cutoff_occurred() checks whether a beta cutoff has occurred in the +// current active split point, or in some ancestor of the split point. bool Thread::cutoff_occurred() const { @@ -143,12 +173,12 @@ bool Thread::cutoff_occurred() const { } -// is_available_to() checks whether the thread is available to help the thread with -// threadID "master" at a split point. An obvious requirement is that thread must be -// idle. With more than two threads, this is not by itself sufficient: If the thread -// is the master of some active split point, it is only available as a slave to the -// threads which are busy searching the split point at the top of "slave"'s split -// point stack (the "helpful master concept" in YBWC terminology). +// Thread::is_available_to() checks whether the thread is available to help the +// thread with threadID "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 active split point, it is only available as a +// slave to the threads which are busy searching the split point at the top of +// "slave"'s split point stack (the "helpful master concept" in YBWC terminology). bool Thread::is_available_to(int master) const { @@ -165,104 +195,82 @@ bool Thread::is_available_to(int master) const { } -// read_uci_options() updates internal threads parameters from the corresponding -// UCI options. It is called before to start a new search. +// init() is called at startup. Initializes lock and condition variable and +// launches requested threads sending them immediately to sleep. We cannot use +// 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::read_uci_options() { - - maxThreadsPerSplitPoint = Options["Max Threads per Split Point"]; - minimumSplitDepth = Options["Min Split Depth"] * ONE_PLY; - useSleepingThreads = Options["Use Sleeping Threads"]; - activeThreads = Options["Threads"]; +void ThreadsManager::init() { - // Dynamically allocate pawn and material hash tables according to the - // number of active threads. This avoids preallocating memory for all - // possible threads if only few are used. - for (int i = 0; i < MAX_THREADS; i++) - if (i < activeThreads) - { - threads[i].pawnTable.init(); - threads[i].materialTable.init(); - threads[i].maxPly = 0; - } + cond_init(sleepCond); + lock_init(splitLock); + timer = new Thread(&Thread::timer_loop); + threads.push_back(new Thread(&Thread::main_loop)); + read_uci_options(); } -void ThreadsManager::wake_up() { - - for (int i = 0; i < activeThreads; i++) - { - threads[i].do_sleep = false; - threads[i].wake_up(); - } -} +// d'tor cleanly terminates the threads when the program exits. +ThreadsManager::~ThreadsManager() { -void ThreadsManager::sleep() { + for (int i = 0; i < size(); i++) + delete threads[i]; - for (int i = 0; i < activeThreads; i++) - threads[i].do_sleep = true; + delete timer; + lock_destroy(splitLock); + cond_destroy(sleepCond); } -// init() is called during startup. Initializes locks and condition variables -// and launches all threads sending them immediately to sleep. +// 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 in advance all possible +// threads, with included pawns and material tables, if only few are used. -void ThreadsManager::init() { +void ThreadsManager::read_uci_options() { - 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"]; - cond_init(sleepCond); - lock_init(splitLock); + assert(requested > 0); - // Allocate main thread tables to call evaluate() also when not searching - threads[0].pawnTable.init(); - threads[0].materialTable.init(); + while (size() < requested) + threads.push_back(new Thread(&Thread::idle_loop)); - // Create and launch all the threads, threads will go immediately to sleep - for (int i = 0; i <= MAX_THREADS; i++) + while (size() > requested) { - threads[i].is_searching = false; - threads[i].do_sleep = (i != 0); // Avoid a race with start_thinking() - threads[i].threadID = i; - - lock_init(threads[i].sleepLock); - cond_init(threads[i].sleepCond); - - for (int j = 0; j < MAX_SPLITPOINTS_PER_THREAD; j++) - lock_init(threads[i].splitPoints[j].lock); - - if (!thread_create(threads[i].handle, start_routine, threads[i])) - { - std::cerr << "Failed to create thread number " << i << std::endl; - ::exit(EXIT_FAILURE); - } + delete threads.back(); + threads.pop_back(); } } -// exit() is called to cleanly terminate the threads when the program finishes +// 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 ThreadsManager::exit() { +void ThreadsManager::wake_up() const { - for (int i = 0; i <= MAX_THREADS; i++) + for (int i = 0; i < size(); i++) { - assert(threads[i].do_sleep); + threads[i]->maxPly = 0; - threads[i].do_exit = true; // Search must be already finished - threads[i].wake_up(); + if (!useSleepingThreads) + threads[i]->wake_up(); + } +} - thread_join(threads[i].handle); // Wait for thread termination - lock_destroy(threads[i].sleepLock); - cond_destroy(threads[i].sleepCond); +// sleep() is called after the search finishes to ask all the threads but the +// main one to go waiting on a sleep condition. - for (int j = 0; j < MAX_SPLITPOINTS_PER_THREAD; j++) - lock_destroy(threads[i].splitPoints[j].lock); - } +void ThreadsManager::sleep() const { - lock_destroy(splitLock); - cond_destroy(sleepCond); + 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() } @@ -271,10 +279,10 @@ void ThreadsManager::exit() { bool ThreadsManager::available_slave_exists(int master) const { - assert(master >= 0 && master < activeThreads); + assert(master >= 0 && master < size()); - for (int i = 0; i < activeThreads; i++) - if (threads[i].is_available_to(master)) + for (int i = 0; i < size(); i++) + if (threads[i]->is_available_to(master)) return true; return false; @@ -300,11 +308,9 @@ Value ThreadsManager::split(Position& pos, Stack* ss, Value alpha, Value beta, assert(alpha < beta); assert(beta <= VALUE_INFINITE); assert(depth > DEPTH_ZERO); - assert(pos.thread() >= 0 && pos.thread() < activeThreads); - assert(activeThreads > 1); int master = pos.thread(); - Thread& masterThread = threads[master]; + Thread& masterThread = *threads[master]; if (masterThread.splitPointsCnt >= MAX_SPLITPOINTS_PER_THREAD) return bestValue; @@ -340,15 +346,15 @@ Value ThreadsManager::split(Position& pos, Stack* ss, Value alpha, Value beta, lock_grab(sp->lock); lock_grab(splitLock); - for (int i = 0; i < activeThreads && !Fake; i++) - if (threads[i].is_available_to(master)) + for (int i = 0; i < size() && !Fake; ++i) + if (threads[i]->is_available_to(master)) { sp->slavesMask |= 1ULL << i; - threads[i].curSplitPoint = sp; - threads[i].is_searching = true; // Slave leaves idle_loop() + threads[i]->curSplitPoint = sp; + threads[i]->is_searching = true; // Slave leaves idle_loop() if (useSleepingThreads) - threads[i].wake_up(); + threads[i]->wake_up(); if (++slavesCnt + 1 >= maxThreadsPerSplitPoint) // Master is always included break; @@ -399,72 +405,47 @@ template Value ThreadsManager::split(Position&, Stack*, Value, Value, Valu void ThreadsManager::set_timer(int msec) { - Thread& timer = threads[MAX_THREADS]; + lock_grab(timer->sleepLock); + timer->maxPly = msec; + cond_signal(timer->sleepCond); // Wake up and restart the timer + lock_release(timer->sleepLock); +} + - lock_grab(timer.sleepLock); - timer.maxPly = msec; - cond_signal(timer.sleepCond); // Wake up and restart the timer - lock_release(timer.sleepLock); +// ThreadsManager::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() { + + Thread* main = threads[0]; + lock_grab(main->sleepLock); + while (!main->do_sleep) cond_wait(sleepCond, main->sleepLock); + lock_release(main->sleepLock); } -// ThreadsManager::start_thinking() is used by UI thread to wake up the main -// thread parked in main_loop() and starting a new search. If asyncMode is true +// ThreadsManager::start_searching() is used by UI thread to wake up the main +// thread parked in main_loop() and starting a new search. If async is true // then function returns immediately, otherwise caller is blocked waiting for // the search to finish. -void ThreadsManager::start_thinking(const Position& pos, const LimitsType& limits, - const std::set& searchMoves, bool async) { - Thread& main = threads[0]; - - lock_grab(main.sleepLock); +void ThreadsManager::start_searching(const Position& pos, const LimitsType& limits, + const std::set& searchMoves, bool async) { + wait_for_search_finished(); - // Wait main thread has finished before to launch a new search - while (!main.do_sleep) - cond_wait(sleepCond, main.sleepLock); + Signals.stopOnPonderhit = Signals.firstRootMove = false; + Signals.stop = Signals.failedLowAtRoot = false; - // Copy input arguments to initialize the search RootPosition.copy(pos, 0); Limits = limits; RootMoves.clear(); - // Populate RootMoves with all the legal moves (default) or, if a searchMoves - // set is given, with the subset of legal moves to search. for (MoveList ml(pos); !ml.end(); ++ml) if (searchMoves.empty() || searchMoves.count(ml.move())) RootMoves.push_back(RootMove(ml.move())); - // Reset signals before to start the new search - Signals.stopOnPonderhit = Signals.firstRootMove = false; - Signals.stop = Signals.failedLowAtRoot = false; - - main.do_sleep = false; - cond_signal(main.sleepCond); // Wake up main thread and start searching + threads[0]->wake_up(); // Start main thread if (!async) - while (!main.do_sleep) - cond_wait(sleepCond, main.sleepLock); - - lock_release(main.sleepLock); -} - - -// ThreadsManager::stop_thinking() is used by UI thread to raise a stop request -// and to wait for the main thread finishing the search. Needed to wait exiting -// and terminate the threads after a 'quit' command. - -void ThreadsManager::stop_thinking() { - - Thread& main = threads[0]; - - Search::Signals.stop = true; - - lock_grab(main.sleepLock); - - cond_signal(main.sleepCond); // In case is waiting for stop or ponderhit - - while (!main.do_sleep) - cond_wait(sleepCond, main.sleepLock); - - lock_release(main.sleepLock); + wait_for_search_finished(); }