X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fthread.cpp;h=bd20361daff658cd31a9e955fe585d3473a1c7e4;hp=80765cdeba0a981e2bbe21120e1694f355c5040c;hb=5cbcff55cc3a2ff78dd83e7a3f94c5414946f82c;hpb=50a7200b18e96a6f0e2c2ee7fda017ea6f2f1c1f diff --git a/src/thread.cpp b/src/thread.cpp index 80765cde..bd20361d 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) 2008-2012 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 @@ -19,59 +19,116 @@ #include // For std::count #include -#include // For memset -#include #include "movegen.h" #include "search.h" #include "thread.h" -#include "ucioption.h" +#include "uci.h" using namespace Search; ThreadPool Threads; // Global object -namespace { extern "C" { +extern void check_time(); + +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(). - 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 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); // Will go to sleep + return 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 + delete th; + } + +} + -} } +// notify_one() wakes up the thread when there is some work to do +void ThreadBase::notify_one() { + + mutex.lock(); + sleepCondition.notify_one(); + mutex.unlock(); +} -// Thread c'tor starts a newly-created thread of execution that will call -// the the virtual function idle_loop(), going immediately to sleep. + +// 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; - idx = Threads.size(); + activePosition = NULL; + idx = Threads.size(); // Starts from 0 +} - if (!thread_create(handle, start_routine, this)) - { - std::cerr << "Failed to create thread number " << idx << std::endl; - ::exit(EXIT_FAILURE); - } + +// 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 d'tor waits for thread termination before to return +// 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). -Thread::~Thread() { +bool Thread::available_to(const Thread* master) const { - exit = true; // Search must be already finished - notify_one(); - thread_join(handle); // Wait for thread termination + 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() { @@ -80,18 +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() { @@ -103,7 +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); } @@ -123,117 +180,66 @@ 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. - -bool Thread::cutoff_occurred() const { - - for (SplitPoint* sp = activeSplitPoint; sp; sp = sp->parentSplitPoint) - if (sp->cutoff) - return true; - - return false; -} - - -// 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 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(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 TimerThread(); - push_back(new MainThread()); + 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() { - delete timer; // As first because check_time() accesses threads data + delete_thread(timer); // As first because check_time() accesses threads data for (iterator it = begin(); it != end(); ++it) - delete *it; + delete_thread(*it); } // 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); + // If zero (default) then set best minimum split depth automatically + if (!minimumSplitDepth) + minimumSplitDepth = requested < 8 ? 4 * ONE_PLY : 7 * ONE_PLY; + while (size() < requested) - push_back(new Thread()); + push_back(new_thread()); while (size() > requested) { - delete back(); + delete_thread(back()); pop_back(); } } -// 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(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; @@ -249,14 +255,12 @@ Thread* ThreadPool::available_slave(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, Stack* ss, Value alpha, Value beta, Value* bestValue, - Move* bestMove, Depth depth, Move threatMove, int moveCount, - MovePicker* movePicker, int nodeType) { +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()); - 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); @@ -266,14 +270,14 @@ void Thread::split(Position& pos, Stack* ss, Value alpha, Value beta, Value* bes 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; + sp.cutNode = cutNode; sp.movePicker = movePicker; sp.moveCount = moveCount; sp.pos = &pos; @@ -281,54 +285,50 @@ void Thread::split(Position& pos, Stack* ss, Value alpha, Value beta, Value* bes sp.cutoff = false; sp.ss = ss; - memset(sp.slavesPositions, 0, sizeof(sp.slavesPositions)); - // Try to allocate available threads and ask them to start searching setting // 'searching' flag. This must be done under lock protection to avoid concurrent // allocation of the same slave by another master. 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 } - sp.mutex.unlock(); - Threads.mutex.unlock(); - // Everything is set up. The master thread enters the idle loop, from which // 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) - { - Thread::idle_loop(); // Force a call to base class idle_loop() + sp.mutex.unlock(); + Threads.mutex.unlock(); - // 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); - } + Thread::idle_loop(); // Force a call to base class idle_loop() + + // 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); *bestMove = sp.bestMove; *bestValue = sp.bestValue; @@ -337,16 +337,11 @@ void Thread::split(Position& pos, Stack* ss, Value alpha, Value beta, Value* bes Threads.mutex.unlock(); } -// Explicit template instantiations -template void Thread::split(Position&, Stack*, Value, Value, Value*, Move*, Depth, Move, int, MovePicker*, int); -template void Thread::split< true>(Position&, Stack*, Value, Value, Value*, Move*, Depth, Move, int, MovePicker*, int); - - // 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(); @@ -356,8 +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 @@ -365,16 +360,20 @@ void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits, Signals.stopOnPonderhit = Signals.firstRootMove = false; Signals.stop = Signals.failedLowAtRoot = false; + RootMoves.clear(); RootPos = pos; Limits = limits; - SetupStates = states; // Ownership transfer here - RootMoves.clear(); + if (states.get()) // If we don't set a new position, preserve current state + { + SetupStates = states; // Ownership transfer here + assert(!states.get()); + } - for (MoveList ml(pos); !ml.end(); ++ml) - if ( searchMoves.empty() - || std::count(searchMoves.begin(), searchMoves.end(), ml.move())) - RootMoves.push_back(RootMove(ml.move())); + for (MoveList it(pos); *it; ++it) + if ( limits.searchmoves.empty() + || std::count(limits.searchmoves.begin(), limits.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 }