X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fthread.cpp;h=eb991f65abdead61f07403a70de375913a5a478d;hp=25ef1853c03755762db7645771ffdccfb599ff26;hb=f196c1bad8928b502c0ad1abd86c35ab53d3468e;hpb=4d46d29efe4ee496bda2aa7ea83184d502944852 diff --git a/src/thread.cpp b/src/thread.cpp index 25ef1853..eb991f65 100644 --- a/src/thread.cpp +++ b/src/thread.cpp @@ -34,20 +34,20 @@ namespace { // start_routine() is the C function which is called when a new thread // is launched. It is a wrapper to the virtual function idle_loop(). - extern "C" { long start_routine(Thread* th) { th->idle_loop(); return 0; } } + extern "C" { long start_routine(ThreadBase* th) { th->idle_loop(); return 0; } } // Helpers to launch a thread after creation and joining before delete. Must be - // outside Thread c'tor and d'tor because object shall be fully initialized + // outside Thread c'tor and d'tor because the object will be fully initialized // when start_routine (and hence virtual idle_loop) is called and when joining. template T* new_thread() { T* th = new T(); - thread_create(th->handle, start_routine, th); + thread_create(th->handle, start_routine, th); // Will go to sleep return th; } - void delete_thread(Thread* th) { + void delete_thread(ThreadBase* th) { th->exit = true; // Search must be already finished th->notify_one(); thread_join(th->handle); // Wait for thread termination @@ -57,12 +57,32 @@ namespace { } -// Thread c'tor starts a newly-created thread of execution that will call -// the the virtual function idle_loop(), going immediately to sleep. +// ThreadBase::notify_one() wakes up the thread when there is some work to do + +void ThreadBase::notify_one() { + + mutex.lock(); + sleepCondition.notify_one(); + mutex.unlock(); +} + + +// ThreadBase::wait_for() set the thread to sleep until condition 'b' turns true + +void ThreadBase::wait_for(volatile const bool& b) { + + mutex.lock(); + while (!b) sleepCondition.wait(mutex); + mutex.unlock(); +} + + +// Thread c'tor just inits data and does not launch any execution thread. +// Such a thread will only be started when c'tor returns. Thread::Thread() /* : splitPoints() */ { // Value-initialization bug in MSVC - searching = exit = false; + searching = false; maxPly = splitPointsSize = 0; activeSplitPoint = NULL; activePosition = NULL; @@ -71,7 +91,7 @@ Thread::Thread() /* : splitPoints() */ { // Value-initialization bug in MSVC // 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. +// and then calls check_time(). If msec is 0 thread sleeps until it's woken up. extern void check_time(); void TimerThread::idle_loop() { @@ -81,18 +101,18 @@ void TimerThread::idle_loop() { mutex.lock(); if (!exit) - sleepCondition.wait_for(mutex, msec ? msec : INT_MAX); + sleepCondition.wait_for(mutex, run ? Resolution : INT_MAX); mutex.unlock(); - if (msec) + if (run) check_time(); } } // 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. +// when there is a new search. The main thread will launch all the slave threads. void MainThread::idle_loop() { @@ -104,7 +124,7 @@ void MainThread::idle_loop() { while (!thinking && !exit) { - Threads.sleepCondition.notify_one(); // Wake up UI thread if needed + Threads.sleepCondition.notify_one(); // Wake up the UI thread if needed sleepCondition.wait(mutex); } @@ -124,26 +144,6 @@ void MainThread::idle_loop() { } -// Thread::notify_one() wakes up the thread when there is some search to do - -void Thread::notify_one() { - - mutex.lock(); - sleepCondition.notify_one(); - mutex.unlock(); -} - - -// Thread::wait_for() set the thread to sleep until condition 'b' turns true - -void Thread::wait_for(volatile const bool& b) { - - mutex.lock(); - while (!b) sleepCondition.wait(mutex); - mutex.unlock(); -} - - // Thread::cutoff_occurred() checks whether a beta cutoff has occurred in the // current active split point, or in some ancestor of the split point. @@ -157,20 +157,20 @@ bool Thread::cutoff_occurred() const { } -// Thread::is_available_to() checks whether the thread is available to help the +// Thread::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 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 +// 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(Thread* master) const { +bool Thread::available_to(const Thread* master) const { if (searching) return false; - // Make a local copy to be sure doesn't become zero under our feet while - // testing next condition and so leading to an out of bound access. + // Make a local copy to be sure it doesn't become zero under our feet while + // testing next condition and so leading to an out of bounds access. int size = splitPointsSize; // No split points means that the thread is available as a slave for any @@ -181,7 +181,7 @@ bool Thread::is_available_to(Thread* master) const { // init() is called at startup to create and launch requested threads, that will // go immediately to sleep due to 'sleepWhileIdle' set to true. We cannot use -// a c'tor becuase Threads is a static object and we need a fully initialized +// a c'tor because 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 ThreadPool::init() { @@ -206,8 +206,9 @@ void ThreadPool::exit() { // 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. +// objects are dynamically allocated to avoid creating all possible threads +// in advance (which include pawns and material tables), even if only a few +// are to be used. void ThreadPool::read_uci_options() { @@ -217,6 +218,13 @@ void ThreadPool::read_uci_options() { assert(requested > 0); + // Value 0 has a special meaning: We determine the optimal minimum split depth + // automatically. Anyhow the minimumSplitDepth should never be under 4 plies. + if (!minimumSplitDepth) + minimumSplitDepth = (requested < 8 ? 4 : 7) * ONE_PLY; + else + minimumSplitDepth = std::max(4 * ONE_PLY, minimumSplitDepth); + while (size() < requested) push_back(new_thread()); @@ -231,10 +239,10 @@ void ThreadPool::read_uci_options() { // slave_available() tries to find an idle thread which is available as a slave // for the thread 'master'. -Thread* ThreadPool::available_slave(Thread* master) const { +Thread* ThreadPool::available_slave(const Thread* master) const { for (const_iterator it = begin(); it != end(); ++it) - if ((*it)->is_available_to(master)) + if ((*it)->available_to(master)) return *it; return NULL; @@ -251,8 +259,8 @@ Thread* ThreadPool::available_slave(Thread* master) const { // search() then split() returns. template -void Thread::split(Position& pos, Stack* ss, Value alpha, Value beta, Value* bestValue, - Move* bestMove, Depth depth, Move threatMove, int moveCount, +void Thread::split(Position& pos, const Stack* ss, Value alpha, Value beta, Value* bestValue, + Move* bestMove, Depth depth, int moveCount, MovePicker* movePicker, int nodeType, bool cutNode) { assert(pos.pos_is_ok()); @@ -271,7 +279,6 @@ void Thread::split(Position& pos, Stack* ss, Value alpha, Value beta, Value* bes sp.depth = depth; sp.bestValue = *bestValue; sp.bestMove = *bestMove; - sp.threatMove = threatMove; sp.alpha = alpha; sp.beta = beta; sp.nodeType = nodeType; @@ -289,7 +296,7 @@ void Thread::split(Position& pos, Stack* ss, Value alpha, Value beta, Value* bes Threads.mutex.lock(); sp.mutex.lock(); - splitPointsSize++; + ++splitPointsSize; activeSplitPoint = &sp; activePosition = NULL; @@ -316,20 +323,21 @@ void Thread::split(Position& pos, Stack* ss, Value alpha, Value beta, Value* bes 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. + // In the helpful master concept, a master can help only a sub-tree of its + // split point and because everything is finished here, it's not possible + // for the master to be booked. assert(!searching); assert(!activePosition); // We have returned from the idle loop, which means that all threads are // finished. Note that setting 'searching' and decreasing splitPointsSize is - // done under lock protection to avoid a race with Thread::is_available_to(). + // done under lock protection to avoid a race with Thread::available_to(). Threads.mutex.lock(); sp.mutex.lock(); } searching = true; - splitPointsSize--; + --splitPointsSize; activeSplitPoint = sp.parentSplitPoint; activePosition = &pos; pos.set_nodes_searched(pos.nodes_searched() + sp.nodes); @@ -341,15 +349,15 @@ void Thread::split(Position& pos, Stack* ss, Value alpha, Value beta, Value* bes } // Explicit template instantiations -template void Thread::split(Position&, Stack*, Value, Value, Value*, Move*, Depth, Move, int, MovePicker*, int, bool); -template void Thread::split< true>(Position&, Stack*, Value, Value, Value*, Move*, Depth, Move, int, MovePicker*, int, bool); +template void Thread::split(Position&, const Stack*, Value, Value, Value*, Move*, Depth, int, MovePicker*, int, bool); +template void Thread::split< true>(Position&, const Stack*, Value, Value, Value*, Move*, Depth, int, MovePicker*, int, bool); // wait_for_think_finished() waits for main thread to go to sleep then returns void ThreadPool::wait_for_think_finished() { - MainThread* t = main_thread(); + MainThread* t = main(); t->mutex.lock(); while (t->thinking) sleepCondition.wait(t->mutex); t->mutex.unlock(); @@ -382,6 +390,6 @@ void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits, || std::count(searchMoves.begin(), searchMoves.end(), *it)) RootMoves.push_back(RootMove(*it)); - main_thread()->thinking = true; - main_thread()->notify_one(); // Starts main thread + main()->thinking = true; + main()->notify_one(); // Starts main thread }