X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fthread.cpp;h=f2a2c821151aa0219d525be1779e83d86c9dd2d1;hp=9f5a13f8624dac701d3827ee0d2beefca76e8cf4;hb=32d3a07c6710e84d78999cb69c6a866b0bfff482;hpb=b978eb05dcce5eb874bb45e30af854d332b9738f diff --git a/src/thread.cpp b/src/thread.cpp index 9f5a13f8..f2a2c821 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; } @@ -49,7 +49,8 @@ Thread::Thread(Fn fn) { curSplitPoint = NULL; start_fn = fn; threadID = Threads.size(); - do_sleep = (threadID != 0); // Avoid a race with start_thinking() + + do_sleep = (fn != &Thread::main_loop); // Avoid a race with start_thinking() lock_init(sleepLock); cond_init(sleepCond); @@ -65,7 +66,7 @@ Thread::Thread(Fn fn) { } -// 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() { @@ -161,8 +162,8 @@ void Thread::wait_for_stop_or_ponderhit() { } -// 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 { @@ -174,12 +175,12 @@ 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 { @@ -196,6 +197,34 @@ bool Thread::is_available_to(int master) const { } +// 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); +} + + // 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 @@ -222,10 +251,10 @@ 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++) { @@ -238,42 +267,16 @@ void ThreadsManager::wake_up() { } -// sleep() is called after the search to ask all the threads but the main to go -// waiting on a 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 = 1; i < size(); i++) // Main thread will go to sleep by itself threads[i]->do_sleep = true; // to avoid a race with start_thinking() } -// 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); -} - - // available_slave_exists() tries to find an idle thread which is available as // a slave for the thread with threadID 'master'. @@ -413,7 +416,7 @@ 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 +// 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. @@ -423,25 +426,20 @@ void ThreadsManager::start_thinking(const Position& pos, const LimitsType& limit lock_grab(main.sleepLock); - // Wait main thread has finished before to launch a new search while (!main.do_sleep) - cond_wait(sleepCond, main.sleepLock); + cond_wait(sleepCond, main.sleepLock); // Wait main thread has finished + + 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 @@ -454,8 +452,8 @@ void ThreadsManager::start_thinking(const Position& pos, const LimitsType& limit // 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. +// and to wait for the main thread finishing the search. We cannot return before +// main has finished to avoid a crash in case of a 'quit' command. void ThreadsManager::stop_thinking() {