X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fthread.cpp;h=30177a3915a84c9245644d779ca6fe0d99bc5a2b;hb=HEAD;hp=eb64f7ee372151ec5966d08477f9b9a040b3ef78;hpb=00d9e9fd283b31e63389af091b158dbc3fedfc0e;p=stockfish diff --git a/src/thread.cpp b/src/thread.cpp index eb64f7ee..de8de87d 100644 --- a/src/thread.cpp +++ b/src/thread.cpp @@ -1,7 +1,6 @@ /* 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) 2004-2023 The Stockfish developers (see AUTHORS file) Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -17,244 +16,262 @@ along with this program. If not, see . */ -#include // For std::count -#include +#include "thread.h" +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "evaluate.h" +#include "misc.h" #include "movegen.h" #include "search.h" -#include "thread.h" +#include "syzygy/tbprobe.h" +#include "tt.h" #include "uci.h" -using namespace Search; - -ThreadPool Threads; // Global object +namespace Stockfish { -extern void check_time(); +ThreadPool Threads; // Global object -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) { - - 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; - } +// Constructor launches the thread and waits until it goes to sleep +// in idle_loop(). Note that 'searching' and 'exit' should be already set. +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 +// Destructor wakes up the thread in idle_loop() and waits +// for its termination. Thread should be already waiting. +Thread::~Thread() { -void ThreadBase::notify_one() { + assert(!searching); - std::unique_lock lk(mutex); - sleepCondition.notify_one(); + exit = true; + start_searching(); + stdThread.join(); } -// ThreadBase::wait() set the thread to sleep until 'condition' turns true +// Reset histories, usually before a new game +void Thread::clear() { -void ThreadBase::wait(std::atomic& condition) { + counterMoves.fill(MOVE_NONE); + mainHistory.fill(0); + captureHistory.fill(0); + pawnHistory.fill(0); - std::unique_lock lk(mutex); - sleepCondition.wait(lk, [&]{ return bool(condition); }); + for (bool inCheck : {false, true}) + for (StatsType c : {NoCaptures, Captures}) + for (auto& to : continuationHistory[inCheck][c]) + for (auto& h : to) + h->fill(-71); } -// ThreadBase::wait_while() set the thread to sleep until 'condition' turns false -void ThreadBase::wait_while(std::atomic& condition) { - - std::unique_lock lk(mutex); - sleepCondition.wait(lk, [&]{ return !condition; }); +// Wakes up the thread that will start the search +void Thread::start_searching() { + mutex.lock(); + searching = true; + mutex.unlock(); // Unlock before notifying saves a few CPU-cycles + cv.notify_one(); // Wake up the thread in idle_loop() } -// Thread c'tor makes some init but does not launch any execution thread that -// will be started only when c'tor returns. - -Thread::Thread() { - - searching = false; - maxPly = 0; - history.clear(); - counterMoves.clear(); - idx = Threads.size(); // Starts from 0 -} - - -// 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 TimerThread::idle_loop() { - - while (!exit) - { - std::unique_lock lk(mutex); - - if (!exit) - sleepCondition.wait_for(lk, std::chrono::milliseconds(run ? Resolution : INT_MAX)); - - lk.unlock(); +// Blocks on the condition variable +// until the thread has finished searching. +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 gets parked here, blocked on the +// condition variable, when it has no work to do. void Thread::idle_loop() { - while (!exit) - { - std::unique_lock lk(mutex); + // 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); - while (!searching && !exit) - sleepCondition.wait(lk); + while (true) + { + std::unique_lock lk(mutex); + searching = false; + cv.notify_one(); // Wake up anyone waiting for search finished + cv.wait(lk, [&] { return searching; }); - lk.unlock(); + if (exit) + return; - if (!exit && searching) - search(); - } -} + lk.unlock(); + search(); + } +} -// 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. +// Creates/destroys threads to match the requested number. +// Created and launched threads will immediately go to sleep in idle_loop. +// Upon resizing, threads are recreated to allow for binding if necessary. +void ThreadPool::set(size_t requested) { -void MainThread::idle_loop() { + if (threads.size() > 0) // destroy any existing thread(s) + { + main()->wait_for_search_finished(); - while (!exit) - { - std::unique_lock lk(mutex); + while (threads.size() > 0) + delete threads.back(), threads.pop_back(); + } - thinking = false; + if (requested > 0) // create new thread(s) + { + threads.push_back(new MainThread(0)); - while (!thinking && !exit) - { - sleepCondition.notify_one(); // Wake up the UI thread if needed - sleepCondition.wait(lk); - } + while (threads.size() < requested) + threads.push_back(new Thread(threads.size())); + clear(); - lk.unlock(); + // Reallocate the hash with the new threadpool size + TT.resize(size_t(Options["Hash"])); - if (!exit) - think(); - } + // Init thread number dependent search params. + Search::init(); + } } -// MainThread::join() waits for main thread to finish thinking +// Sets threadPool data to initial values +void ThreadPool::clear() { -void MainThread::join() { + for (Thread* th : threads) + th->clear(); - std::unique_lock lk(mutex); - sleepCondition.wait(lk, [&]{ return !thinking; }); + main()->callsCnt = 0; + main()->bestPreviousScore = VALUE_INFINITE; + main()->bestPreviousAverageScore = VALUE_INFINITE; + main()->previousTimeReduction = 1.0; } -// 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. - -void ThreadPool::init() { - - timer = new_thread(); - push_back(new_thread()); - read_uci_options(); +// Wakes up main thread waiting in idle_loop() and +// returns immediately. Main thread will wake up other threads and start the search. +void ThreadPool::start_thinking(Position& pos, + StateListPtr& states, + const Search::LimitsType& limits, + bool ponderMode) { + + main()->wait_for_search_finished(); + + main()->stopOnPonderhit = stop = false; + increaseDepth = true; + main()->ponder = ponderMode; + Search::Limits = limits; + Search::RootMoves rootMoves; + + 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); + + // After ownership transfer 'states' becomes empty, so if we stop the search + // and call 'go' again without setting a new position states.get() == nullptr. + assert(states.get() || setupStates.get()); + + if (states.get()) + setupStates = std::move(states); // Ownership transfer, states is now empty + + // 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 they are set from + // setupStates->back() later. The rootState is per thread, earlier states are shared + // since they are read-only. + for (Thread* th : threads) + { + th->nodes = th->tbHits = th->nmpMinPly = th->bestMoveChanges = 0; + th->rootDepth = th->completedDepth = 0; + th->rootMoves = rootMoves; + th->rootPos.set(pos.fen(), pos.is_chess960(), &th->rootState, th); + th->rootState = setupStates->back(); + th->rootSimpleEval = Eval::simple_eval(pos, pos.side_to_move()); + } + + main()->start_searching(); } - -// 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; - - for (Thread* th : *this) - delete_thread(th); - - clear(); // Get rid of stale pointers +Thread* ThreadPool::get_best_thread() const { + + Thread* bestThread = threads.front(); + std::map votes; + Value minScore = VALUE_NONE; + + // Find the minimum score of all threads + for (Thread* th : threads) + minScore = std::min(minScore, th->rootMoves[0].score); + + // Vote according to score and depth, and select the best thread + auto thread_value = [minScore](Thread* th) { + return (th->rootMoves[0].score - minScore + 14) * int(th->completedDepth); + }; + + for (Thread* th : threads) + votes[th->rootMoves[0].pv[0]] += thread_value(th); + + for (Thread* th : threads) + if (std::abs(bestThread->rootMoves[0].score) >= VALUE_TB_WIN_IN_MAX_PLY) + { + // Make sure we pick the shortest mate / TB conversion or stave off mate the longest + if (th->rootMoves[0].score > bestThread->rootMoves[0].score) + bestThread = th; + } + else if (th->rootMoves[0].score >= VALUE_TB_WIN_IN_MAX_PLY + || (th->rootMoves[0].score > VALUE_TB_LOSS_IN_MAX_PLY + && (votes[th->rootMoves[0].pv[0]] > votes[bestThread->rootMoves[0].pv[0]] + || (votes[th->rootMoves[0].pv[0]] == votes[bestThread->rootMoves[0].pv[0]] + && thread_value(th) * int(th->rootMoves[0].pv.size() > 2) + > thread_value(bestThread) + * int(bestThread->rootMoves[0].pv.size() > 2))))) + bestThread = th; + + return bestThread; } -// 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() { +// Start non-main threads - size_t requested = Options["Threads"]; +void ThreadPool::start_searching() { - assert(requested > 0); - - while (size() < requested) - push_back(new_thread()); - - while (size() > requested) - { - delete_thread(back()); - pop_back(); - } + for (Thread* th : threads) + if (th != threads.front()) + th->start_searching(); } -// ThreadPool::nodes_searched() returns the number of nodes searched +// Wait for non-main threads -int64_t ThreadPool::nodes_searched() { +void ThreadPool::wait_for_search_finished() const { - int64_t nodes = 0; - for (Thread *th : *this) - nodes += th->rootPos.nodes_searched(); - return nodes; + for (Thread* th : threads) + if (th != threads.front()) + th->wait_for_search_finished(); } - -// ThreadPool::start_thinking() wakes up the main thread sleeping in -// MainThread::idle_loop() and starts a new search, then returns immediately. - -void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits, - StateStackPtr& states) { - main()->join(); - - Signals.stopOnPonderhit = Signals.firstRootMove = false; - Signals.stop = Signals.failedLowAtRoot = false; - - main()->rootMoves.clear(); - main()->rootPos = pos; - Limits = limits; - if (states.get()) // If we don't set a new position, preserve current state - { - SetupStates = std::move(states); // Ownership transfer here - assert(!states.get()); - } - - 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)); - - main()->thinking = true; - main()->notify_one(); // Wake up main thread: 'thinking' must be already set -} +} // namespace Stockfish