X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fthread.cpp;h=42c259685e4620da901778bce753d73cb723f1fa;hp=dd8c398cecf2932abcfc73ef57d97e9160eb026a;hb=bc3b148d5712ef9ea00e74d3ff5aea10a4d3cabe;hpb=307a5a4f63169fd215860dc478dcf2a9db2c46e8 diff --git a/src/thread.cpp b/src/thread.cpp index dd8c398c..42c25968 100644 --- a/src/thread.cpp +++ b/src/thread.cpp @@ -2,6 +2,7 @@ Stockfish, a UCI chess playing engine derived from Glaurung 2.1 Copyright (C) 2004-2008 Tord Romstad (Glaurung author) Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, 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 @@ -24,238 +25,179 @@ #include "search.h" #include "thread.h" #include "uci.h" - -using namespace Search; +#include "syzygy/tbprobe.h" +#include "tt.h" ThreadPool Threads; // Global object -extern void check_time(); - -namespace { - - // Helpers to launch a thread after creation and joining before delete. Must be - // outside Thread c'tor and d'tor because the object must be fully initialized - // when start_routine (and hence virtual idle_loop) is called and when joining. - - template T* new_thread() { - std::thread* th = new T; - *th = std::thread(&T::idle_loop, (T*)th); // Will go to sleep - return (T*)th; - } - void delete_thread(ThreadBase* th) { +/// Thread constructor launches the thread and waits until it goes to sleep +/// in idle_loop(). Note that 'searching' and 'exit' should be alredy set. - th->mutex.lock(); - th->exit = true; // Search must be already finished - th->mutex.unlock(); - - th->notify_one(); - th->join(); // Wait for thread termination - delete th; - } +Thread::Thread(size_t n) : idx(n), stdThread(&Thread::idle_loop, this) { + wait_for_search_finished(); } -// ThreadBase::notify_one() wakes up the thread when there is some work to do - -void ThreadBase::notify_one() { +/// Thread destructor wakes up the thread in idle_loop() and waits +/// for its termination. Thread should be already waiting. - std::unique_lock lk(mutex); - sleepCondition.notify_one(); -} +Thread::~Thread() { + assert(!searching); -// ThreadBase::wait() set the thread to sleep until 'condition' turns true - -void ThreadBase::wait(volatile const bool& condition) { - - std::unique_lock lk(mutex); - sleepCondition.wait(lk, [&]{ return condition; }); + exit = true; + start_searching(); + stdThread.join(); } -// ThreadBase::wait_while() set the thread to sleep until 'condition' turns false - -void ThreadBase::wait_while(volatile const bool& condition) { - - std::unique_lock lk(mutex); - sleepCondition.wait(lk, [&]{ return !condition; }); -} +/// Thread::clear() reset histories, usually before a new game +void Thread::clear() { -// Thread c'tor makes some init but does not launch any execution thread that -// will be started only when c'tor returns. + counterMoves.fill(MOVE_NONE); + mainHistory.fill(0); + captureHistory.fill(0); -Thread::Thread() /* : splitPoints() */ { // Initialization of non POD broken in MSVC + for (auto& to : continuationHistory) + for (auto& h : to) + h->fill(0); - searching = false; - maxPly = 0; - history.clear(); - counterMoves.clear(); - idx = Threads.size(); // Starts from 0 + continuationHistory[NO_PIECE][0]->fill(Search::CounterMovePruneThreshold - 1); } +/// Thread::start_searching() wakes up the thread that will start the search -// TimerThread::idle_loop() is where the timer thread waits Resolution milliseconds -// and then calls check_time(). When not searching, thread sleeps until it's woken up. +void Thread::start_searching() { -void TimerThread::idle_loop() { + std::lock_guard lk(mutex); + searching = true; + cv.notify_one(); // Wake up the thread in idle_loop() +} - while (!exit) - { - std::unique_lock lk(mutex); - if (!exit) - sleepCondition.wait_for(lk, std::chrono::milliseconds(run ? Resolution : INT_MAX)); +/// Thread::wait_for_search_finished() blocks on the condition variable +/// until the thread has finished searching. - lk.unlock(); +void Thread::wait_for_search_finished() { - if (!exit && run) - check_time(); - } + std::unique_lock lk(mutex); + cv.wait(lk, [&]{ return !searching; }); } -// Thread::idle_loop() is where the thread is parked when it has no work to do +/// Thread::idle_loop() is where the thread is parked, blocked on the +/// condition variable, when it has no work to do. void Thread::idle_loop() { - while (!exit) - { - std::unique_lock lk(mutex); - - while (!searching && !exit) - sleepCondition.wait(lk); - - lk.unlock(); - - if (!exit && searching) - search(); - } -} + // If OS already scheduled us on a different group than 0 then don't overwrite + // the choice, eventually we are one of many one-threaded processes running on + // some Windows NUMA hardware, for instance in fishtest. To make it simple, + // just check if running threads are below a threshold, in this case all this + // NUMA machinery is not needed. + if (Options["Threads"] > 8) + WinProcGroup::bindThisThread(idx); - -// MainThread::idle_loop() is where the main thread is parked waiting to be started -// when there is a new search. The main thread will launch all the slave threads. - -void MainThread::idle_loop() { - - while (!exit) + while (true) { std::unique_lock lk(mutex); + searching = false; + cv.notify_one(); // Wake up anyone waiting for search finished + cv.wait(lk, [&]{ return searching; }); - thinking = false; - - while (!thinking && !exit) - { - sleepCondition.notify_one(); // Wake up the UI thread if needed - sleepCondition.wait(lk); - } + if (exit) + return; lk.unlock(); - if (!exit) - think(); + search(); } } +/// ThreadPool::set() creates/destroys threads to match the requested number. +/// Created and launched threads will go immediately to sleep in idle_loop. +/// Upon resizing, threads are recreated to allow for binding if necessary. -// MainThread::join() waits for main thread to finish thinking +void ThreadPool::set(size_t requested) { -void MainThread::join() { - - std::unique_lock lk(mutex); - sleepCondition.wait(lk, [&]{ return !thinking; }); -} + if (size() > 0) { // destroy any existing thread(s) + main()->wait_for_search_finished(); + while (size() > 0) + delete back(), pop_back(); + } -// ThreadPool::init() is called at startup to create and launch requested threads, -// that will 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. + if (requested > 0) { // create new thread(s) + push_back(new MainThread(0)); -void ThreadPool::init() { + while (size() < requested) + push_back(new Thread(size())); + clear(); + } - timer = new_thread(); - push_back(new_thread()); - read_uci_options(); + // Reallocate the hash with the new threadpool size + TT.resize(Options["Hash"]); } +/// ThreadPool::clear() sets threadPool data to initial values. -// ThreadPool::exit() terminates the threads before the program exits. Cannot be -// done in d'tor because threads must be terminated before freeing us. - -void ThreadPool::exit() { - - delete_thread(timer); // As first because check_time() accesses threads data - timer = nullptr; +void ThreadPool::clear() { for (Thread* th : *this) - delete_thread(th); + th->clear(); - clear(); // Get rid of stale pointers + main()->callsCnt = 0; + main()->previousScore = VALUE_INFINITE; + main()->previousTimeReduction = 1.0; } +/// ThreadPool::start_thinking() wakes up main thread waiting in idle_loop() and +/// returns immediately. Main thread will wake up other threads and start the search. -// ThreadPool::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 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() { - - size_t requested = Options["Threads"]; - - assert(requested > 0); +void ThreadPool::start_thinking(Position& pos, StateListPtr& states, + const Search::LimitsType& limits, bool ponderMode) { - while (size() < requested) - push_back(new_thread()); - - while (size() > requested) - { - delete_thread(back()); - pop_back(); - } -} + main()->wait_for_search_finished(); + stopOnPonderhit = stop = false; + ponder = ponderMode; + Search::Limits = limits; + Search::RootMoves rootMoves; -// ThreadPool::nodes_searched() returns the number of nodes searched - -int64_t ThreadPool::nodes_searched() { - - int64_t nodes = 0; - for (Thread *th : *this) - nodes += th->rootPos.nodes_searched(); - return nodes; -} + for (const auto& m : MoveList(pos)) + if ( limits.searchmoves.empty() + || std::count(limits.searchmoves.begin(), limits.searchmoves.end(), m)) + rootMoves.emplace_back(m); + if (!rootMoves.empty()) + Tablebases::rank_root_moves(pos, rootMoves); -// ThreadPool::start_thinking() wakes up the main thread sleeping in -// MainThread::idle_loop() and starts a new search, then returns immediately. + // After ownership transfer 'states' becomes empty, so if we stop the search + // and call 'go' again without setting a new position states.get() == NULL. + assert(states.get() || setupStates.get()); -void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits, - StateStackPtr& states) { - main()->join(); + if (states.get()) + setupStates = std::move(states); // Ownership transfer, states is now empty - Signals.stopOnPonderhit = Signals.firstRootMove = false; - Signals.stop = Signals.failedLowAtRoot = false; + // We use Position::set() to set root position across threads. But there are + // some StateInfo fields (previous, pliesFromNull, capturedPiece) that cannot + // be deduced from a fen string, so set() clears them and to not lose the info + // we need to backup and later restore setupStates->back(). Note that setupStates + // is shared by threads but is accessed in read-only mode. + StateInfo tmp = setupStates->back(); - main()->rootMoves.clear(); - main()->rootPos = pos; - Limits = limits; - if (states.get()) // If we don't set a new position, preserve current state + for (Thread* th : *this) { - SetupStates = std::move(states); // Ownership transfer here - assert(!states.get()); + th->nodes = th->tbHits = th->nmpMinPly = 0; + th->rootDepth = th->completedDepth = DEPTH_ZERO; + th->rootMoves = rootMoves; + th->rootPos.set(pos.fen(), pos.is_chess960(), &setupStates->back(), th); } - for (const auto& m : MoveList(pos)) - if ( limits.searchmoves.empty() - || std::count(limits.searchmoves.begin(), limits.searchmoves.end(), m)) - main()->rootMoves.push_back(RootMove(m)); + setupStates->back() = tmp; - main()->thinking = true; - main()->notify_one(); // Wake up main thread: 'thinking' must be already set + main()->start_searching(); }