X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fthread.cpp;h=3b98ac631985200d835796e9512751a17fdda641;hp=782537d765dd6c567c22883b42764e38cb74a479;hb=15e21911110f9d459c4fef2bb17903d97345d0b9;hpb=cca34e234cc98ed4b61e75a25f8cd0d917c2a3fa diff --git a/src/thread.cpp b/src/thread.cpp index 782537d7..3b98ac63 100644 --- a/src/thread.cpp +++ b/src/thread.cpp @@ -1,7 +1,7 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 Copyright (C) 2004-2008 Tord Romstad (Glaurung author) - Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2008-2014 Marco Costalba, Joona Kiiski, Tord Romstad Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -29,6 +29,8 @@ using namespace Search; ThreadPool Threads; // Global object +extern void check_time(); + namespace { // start_routine() is the C function which is called when a new thread @@ -38,7 +40,7 @@ namespace { // 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() { @@ -57,7 +59,7 @@ namespace { } -// ThreadBase::notify_one() wakes up the thread when there is some work to do +// notify_one() wakes up the thread when there is some work to do void ThreadBase::notify_one() { @@ -67,7 +69,7 @@ void ThreadBase::notify_one() { } -// ThreadBase::wait_for() set the thread to sleep until condition 'b' turns true +// wait_for() set the thread to sleep until condition 'b' turns true void ThreadBase::wait_for(volatile const bool& b) { @@ -77,8 +79,8 @@ void ThreadBase::wait_for(volatile const bool& b) { } -// Thread c'tor just inits data but does not launch any thread of execution that -// instead will be started only upon c'tor returns. +// 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 @@ -86,13 +88,47 @@ Thread::Thread() /* : splitPoints() */ { // Value-initialization bug in MSVC maxPly = splitPointsSize = 0; activeSplitPoint = NULL; activePosition = NULL; - idx = Threads.size(); + idx = Threads.size(); // Starts from 0 +} + + +// 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 { + + for (SplitPoint* sp = activeSplitPoint; sp; sp = sp->parentSplitPoint) + if (sp->cutoff) + return true; + + return false; +} + + +// 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 slave's split point +// stack (the "helpful master concept" in YBWC terminology). + +bool Thread::available_to(const Thread* master) const { + + if (searching) + return false; + + // 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. + const int size = splitPointsSize; + + // No split points means that the thread is available as a slave for any + // other thread otherwise apply the "helpful master" concept if possible. + return !size || splitPoints[size - 1].slavesMask.test(master->idx); } // 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(); +// and then calls check_time(). If msec is 0 thread sleeps until it's woken up. void TimerThread::idle_loop() { @@ -101,18 +137,18 @@ 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() { @@ -124,7 +160,7 @@ 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); } @@ -144,56 +180,21 @@ void MainThread::idle_loop() { } -// 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 { - - for (SplitPoint* sp = activeSplitPoint; sp; sp = sp->parentSplitPoint) - if (sp->cutoff) - return true; - - return false; -} - - -// 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 -// stack (the "helpful master concept" in YBWC terminology). - -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. - int size = splitPointsSize; - - // No split points means that the thread is available as a slave for any - // other thread otherwise apply the "helpful master" concept if possible. - return !size || (splitPoints[size - 1].slavesMask & (1ULL << master->idx)); -} - - // 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 -// engine at this point due to allocation of Endgames in Thread c'tor. +// go immediately to sleep. We cannot use 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() { - sleepWhileIdle = true; timer = new_thread(); push_back(new_thread()); read_uci_options(); } -// exit() cleanly terminates the threads before the program exits +// exit() cleanly terminates the threads before the program exits. Cannot be done in +// d'tor because we have to terminate the threads before to free ThreadPool object. void ThreadPool::exit() { @@ -206,23 +207,20 @@ 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() { - maxThreadsPerSplitPoint = Options["Max Threads per Split Point"]; - minimumSplitDepth = Options["Min Split Depth"] * ONE_PLY; - size_t requested = Options["Threads"]; + minimumSplitDepth = Options["Min Split Depth"] * ONE_PLY; + size_t requested = Options["Threads"]; 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 zero (default) then set best minimum split depth automatically if (!minimumSplitDepth) - minimumSplitDepth = (requested < 8 ? 4 : 7) * ONE_PLY; - else - minimumSplitDepth = std::max(4 * ONE_PLY, minimumSplitDepth); + minimumSplitDepth = requested < 8 ? 4 * ONE_PLY : 7 * ONE_PLY; while (size() < requested) push_back(new_thread()); @@ -235,7 +233,7 @@ void ThreadPool::read_uci_options() { } -// slave_available() tries to find an idle thread which is available as a slave +// available_slave() tries to find an idle thread which is available as a slave // for the thread 'master'. Thread* ThreadPool::available_slave(const Thread* master) const { @@ -257,14 +255,12 @@ Thread* ThreadPool::available_slave(const Thread* master) const { // leave their idle loops and call search(). When all threads have returned from // search() then split() returns. -template void Thread::split(Position& pos, const Stack* ss, Value alpha, Value beta, Value* bestValue, - Move* bestMove, Depth depth, Move threatMove, int moveCount, + Move* bestMove, Depth depth, int moveCount, MovePicker* movePicker, int nodeType, bool cutNode) { assert(pos.pos_is_ok()); - assert(*bestValue <= alpha && alpha < beta && beta <= VALUE_INFINITE); - assert(*bestValue > -VALUE_INFINITE); + assert(-VALUE_INFINITE < *bestValue && *bestValue <= alpha && alpha < beta && beta <= VALUE_INFINITE); assert(depth >= Threads.minimumSplitDepth); assert(searching); assert(splitPointsSize < MAX_SPLITPOINTS_PER_THREAD); @@ -274,11 +270,10 @@ void Thread::split(Position& pos, const Stack* ss, Value alpha, Value beta, Valu sp.masterThread = this; sp.parentSplitPoint = activeSplitPoint; - sp.slavesMask = 1ULL << idx; + sp.slavesMask = 0, sp.slavesMask.set(idx); sp.depth = depth; sp.bestValue = *bestValue; sp.bestMove = *bestMove; - sp.threatMove = threatMove; sp.alpha = alpha; sp.beta = beta; sp.nodeType = nodeType; @@ -296,17 +291,14 @@ void Thread::split(Position& pos, const Stack* ss, Value alpha, Value beta, Valu Threads.mutex.lock(); sp.mutex.lock(); - splitPointsSize++; + sp.allSlavesSearching = true; // Must be set under lock protection + ++splitPointsSize; activeSplitPoint = &sp; activePosition = NULL; - size_t slavesCnt = 1; // This thread is always included - Thread* slave; - - while ( (slave = Threads.available_slave(this)) != NULL - && ++slavesCnt <= Threads.maxThreadsPerSplitPoint && !Fake) + for (Thread* slave; (slave = Threads.available_slave(this)) != NULL; ) { - sp.slavesMask |= 1ULL << slave->idx; + sp.slavesMask.set(slave->idx); slave->activeSplitPoint = &sp; slave->searching = true; // Slave leaves idle_loop() slave->notify_one(); // Could be sleeping @@ -316,27 +308,25 @@ void Thread::split(Position& pos, const Stack* ss, Value alpha, Value beta, Valu // it will instantly launch a search, because its 'searching' flag is set. // The thread will return from the idle loop when all slaves have finished // their work at this split point. - if (slavesCnt > 1 || Fake) - { - sp.mutex.unlock(); - Threads.mutex.unlock(); + sp.mutex.unlock(); + Threads.mutex.unlock(); - Thread::idle_loop(); // Force a call to base class idle_loop() + 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(!searching); - assert(!activePosition); + // 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::available_to(). - Threads.mutex.lock(); - sp.mutex.lock(); - } + // 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::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); @@ -347,11 +337,6 @@ void Thread::split(Position& pos, const Stack* ss, Value alpha, Value beta, Valu Threads.mutex.unlock(); } -// Explicit template instantiations -template void Thread::split(Position&, const Stack*, Value, Value, Value*, Move*, Depth, Move, int, MovePicker*, int, bool); -template void Thread::split< true>(Position&, const Stack*, Value, Value, Value*, Move*, Depth, Move, int, MovePicker*, int, bool); - - // wait_for_think_finished() waits for main thread to go to sleep then returns void ThreadPool::wait_for_think_finished() { @@ -366,8 +351,8 @@ void ThreadPool::wait_for_think_finished() { // start_thinking() wakes up the main thread sleeping in MainThread::idle_loop() // so to start a new search, then returns immediately. -void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits, - const std::vector& searchMoves, StateStackPtr& states) { +void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits, StateStackPtr& states) { + wait_for_think_finished(); SearchTime = Time::now(); // As early as possible @@ -385,8 +370,8 @@ void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits, } for (MoveList it(pos); *it; ++it) - if ( searchMoves.empty() - || std::count(searchMoves.begin(), searchMoves.end(), *it)) + if ( limits.searchmoves.empty() + || std::count(limits.searchmoves.begin(), limits.searchmoves.end(), *it)) RootMoves.push_back(RootMove(*it)); main()->thinking = true;