X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fthread.cpp;h=631834da4b9f60c159facb502b5f7e2c0ac3fe04;hp=d67b9fcdef16ba6f5cd0f40c3bb7bb33078665d6;hb=ce159b16b9483f83b9e96ac6bf3d6e2ba7e5619c;hpb=c483ffc773c012b49f4ea2f5bd1d788c1f0dc4ac diff --git a/src/thread.cpp b/src/thread.cpp index d67b9fcd..631834da 100644 --- a/src/thread.cpp +++ b/src/thread.cpp @@ -32,7 +32,7 @@ ThreadsManager 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 member function pointed by start_fn. long start_routine(Thread* th) { (th->*(th->start_fn))(); return 0; } @@ -48,8 +48,9 @@ Thread::Thread(Fn fn) { maxPly = splitPointsCnt = 0; curSplitPoint = NULL; start_fn = fn; - threadID = Threads.size(); - do_sleep = (threadID != 0); // Avoid a race with start_thinking() + idx = Threads.size(); + + do_sleep = (fn != &Thread::main_loop); // Avoid a race with start_searching() lock_init(sleepLock); cond_init(sleepCond); @@ -59,13 +60,13 @@ Thread::Thread(Fn fn) { if (!thread_create(handle, start_routine, this)) { - std::cerr << "Failed to create thread number " << threadID << std::endl; + std::cerr << "Failed to create thread number " << idx << std::endl; ::exit(EXIT_FAILURE); } } -// Thread d'tor will wait for thread termination before to return. +// Thread d'tor waits for thread termination before to return. Thread::~Thread() { @@ -85,7 +86,7 @@ Thread::~Thread() { // 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() { @@ -131,7 +132,7 @@ 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() { @@ -153,16 +154,13 @@ 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 { @@ -174,14 +172,14 @@ 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 +// Thread::is_available_to() checks whether the thread is available to help the +// thread '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 +// slaves which are busy searching the split point at the top of slaves split // point stack (the "helpful master concept" in YBWC terminology). -bool Thread::is_available_to(int master) const { +bool Thread::is_available_to(Thread* master) const { if (is_searching) return false; @@ -192,7 +190,35 @@ bool Thread::is_available_to(int master) const { // No active split points means that the thread is available as a slave for any // other thread otherwise apply the "helpful master" concept if possible. - return !spCnt || (splitPoints[spCnt - 1].slavesMask & (1ULL << master)); + return !spCnt || (splitPoints[spCnt - 1].slavesMask & (1ULL << master->idx)); +} + + +// 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::init() { + + cond_init(sleepCond); + lock_init(splitLock); + timer = new Thread(&Thread::timer_loop); + threads.push_back(new Thread(&Thread::main_loop)); + read_uci_options(); +} + + +// d'tor cleanly terminates the threads when the program exits. + +ThreadsManager::~ThreadsManager() { + + for (int i = 0; i < size(); i++) + delete threads[i]; + + delete timer; + lock_destroy(splitLock); + cond_destroy(sleepCond); } @@ -222,13 +248,14 @@ void ThreadsManager::read_uci_options() { // wake_up() is called before a new search to start the threads that are waiting -// on the sleep condition. If useSleepingThreads is set threads will be woken up -// at split time. +// on the sleep condition and to reset maxPly. When useSleepingThreads is set +// threads will be woken up at split time. -void ThreadsManager::wake_up() { +void ThreadsManager::wake_up() const { for (int i = 0; i < size(); i++) { + threads[i]->maxPly = 0; threads[i]->do_sleep = false; if (!useSleepingThreads) @@ -237,47 +264,20 @@ void ThreadsManager::wake_up() { } -// sleep() is called after the search to ask threads to wait on sleep condition +// 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() { +void ThreadsManager::sleep() const { - for (int i = 0; i < size(); i++) - threads[i]->do_sleep = true; -} - - -// init() is called during startup. Initializes locks and condition variables -// and launches all threads sending them immediately to sleep. - -void ThreadsManager::init() { - - cond_init(sleepCond); - lock_init(splitLock); - timer = new Thread(&Thread::timer_loop); - threads.push_back(new Thread(&Thread::main_loop)); - read_uci_options(); -} - - -// exit() is called to cleanly terminate the threads before the program finishes - -void ThreadsManager::exit() { - - for (int i = 0; i < size(); i++) - delete threads[i]; - - delete timer; - 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() } // available_slave_exists() tries to find an idle thread which is available as -// a slave for the thread with threadID 'master'. +// a slave for the thread 'master'. -bool ThreadsManager::available_slave_exists(int master) const { - - assert(master >= 0 && master < size()); +bool ThreadsManager::available_slave_exists(Thread* master) const { for (int i = 0; i < size(); i++) if (threads[i]->is_available_to(master)) @@ -307,19 +307,19 @@ Value ThreadsManager::split(Position& pos, Stack* ss, Value alpha, Value beta, assert(beta <= VALUE_INFINITE); assert(depth > DEPTH_ZERO); - int master = pos.thread(); - Thread& masterThread = *threads[master]; + Thread* master = pos.this_thread(); - if (masterThread.splitPointsCnt >= MAX_SPLITPOINTS_PER_THREAD) + if (master->splitPointsCnt >= MAX_SPLITPOINTS_PER_THREAD) return bestValue; // Pick the next available split point from the split point stack - SplitPoint* sp = &masterThread.splitPoints[masterThread.splitPointsCnt++]; + SplitPoint* sp = &master->splitPoints[master->splitPointsCnt]; - sp->parent = masterThread.curSplitPoint; + sp->parent = master->curSplitPoint; sp->master = master; sp->cutoff = false; - sp->slavesMask = 1ULL << master; + sp->slavesMask = 1ULL << master->idx; + sp->allSlavesRunning = true; sp->depth = depth; sp->bestMove = *bestMove; sp->threatMove = threatMove; @@ -333,9 +333,9 @@ Value ThreadsManager::split(Position& pos, Stack* ss, Value alpha, Value beta, sp->nodes = 0; sp->ss = ss; - assert(masterThread.is_searching); + assert(master->is_searching); - masterThread.curSplitPoint = sp; + master->curSplitPoint = sp; int slavesCnt = 0; // Try to allocate available threads and ask them to start searching setting @@ -358,6 +358,8 @@ Value ThreadsManager::split(Position& pos, Stack* ss, Value alpha, Value beta, break; } + master->splitPointsCnt++; + lock_release(splitLock); lock_release(sp->lock); @@ -368,11 +370,11 @@ Value ThreadsManager::split(Position& pos, Stack* ss, Value alpha, Value beta, // their work at this split point. if (slavesCnt || Fake) { - masterThread.idle_loop(sp); + master->idle_loop(sp); // 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(!masterThread.is_searching); + assert(!master->is_searching); } // We have returned from the idle loop, which means that all threads are @@ -381,9 +383,9 @@ Value ThreadsManager::split(Position& pos, Stack* ss, Value alpha, Value beta, lock_grab(sp->lock); // To protect sp->nodes lock_grab(splitLock); - masterThread.is_searching = true; - masterThread.splitPointsCnt--; - masterThread.curSplitPoint = sp->parent; + master->is_searching = true; + master->splitPointsCnt--; + master->curSplitPoint = sp->parent; pos.set_nodes_searched(pos.nodes_searched() + sp->nodes); *bestMove = sp->bestMove; @@ -410,63 +412,39 @@ void ThreadsManager::set_timer(int msec) { } -// 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 -// 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.front(); - - lock_grab(main.sleepLock); - - // Wait main thread has finished before to launch a new search - while (!main.do_sleep) - cond_wait(sleepCond, main.sleepLock); - - // 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 +// ThreadsManager::wait_for_search_finished() waits for main thread to go to +// sleep, this means search is finished. Then returns. - if (!async) - while (!main.do_sleep) - cond_wait(sleepCond, main.sleepLock); +void ThreadsManager::wait_for_search_finished() { - lock_release(main.sleepLock); + 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); } -// 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. +// ThreadsManager::start_searching() wakes up the main thread sleeping in +// main_loop() so to start a new search, then returns immediately. -void ThreadsManager::stop_thinking() { +void ThreadsManager::start_searching(const Position& pos, const LimitsType& limits, + const std::vector& searchMoves) { + wait_for_search_finished(); - Thread& main = *threads.front(); + SearchTime.restart(); // As early as possible - Search::Signals.stop = true; - - lock_grab(main.sleepLock); + Signals.stopOnPonderhit = Signals.firstRootMove = false; + Signals.stop = Signals.failedLowAtRoot = false; - cond_signal(main.sleepCond); // In case is waiting for stop or ponderhit + RootPosition = pos; + Limits = limits; + RootMoves.clear(); - while (!main.do_sleep) - cond_wait(sleepCond, main.sleepLock); + for (MoveList ml(pos); !ml.end(); ++ml) + if (searchMoves.empty() || count(searchMoves.begin(), searchMoves.end(), ml.move())) + RootMoves.push_back(RootMove(ml.move())); - lock_release(main.sleepLock); + main_thread()->do_sleep = false; + main_thread()->wake_up(); }