X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fthread.cpp;h=c680393e27752135aa95ea76943233bc539fb83e;hp=86fce6aa0c20020b6c54666c874a5231793d6c9e;hb=HEAD;hpb=377d77dbe922b99ee34d686e4fe180698a9b535a diff --git a/src/thread.cpp b/src/thread.cpp index 86fce6aa..de8de87d 100644 --- a/src/thread.cpp +++ b/src/thread.cpp @@ -1,8 +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) 2015-2017 Marco Costalba, Joona Kiiski, Gary Linscott, 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 @@ -18,206 +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 "uci.h" #include "syzygy/tbprobe.h" +#include "tt.h" +#include "uci.h" -ThreadPool Threads; // Global object +namespace Stockfish { -/// Thread constructor launches the thread and then waits until it goes to sleep -/// in idle_loop(). +ThreadPool Threads; // Global object -Thread::Thread() { - exit = false; - selDepth = 0; - nodes = tbHits = 0; - idx = Threads.size(); // Start from 0 +// 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) { - std::unique_lock lk(mutex); - searching = true; - nativeThread = std::thread(&Thread::idle_loop, this); - sleepCondition.wait(lk, [&]{ return !searching; }); + wait_for_search_finished(); } -/// Thread destructor waits for thread termination before returning - +// Destructor wakes up the thread in idle_loop() and waits +// for its termination. Thread should be already waiting. Thread::~Thread() { - mutex.lock(); - exit = true; - sleepCondition.notify_one(); - mutex.unlock(); - nativeThread.join(); -} - + assert(!searching); -/// Thread::wait_for_search_finished() waits on sleep condition -/// until not searching - -void Thread::wait_for_search_finished() { - - std::unique_lock lk(mutex); - sleepCondition.wait(lk, [&]{ return !searching; }); + exit = true; + start_searching(); + stdThread.join(); } -/// Thread::wait() waits on sleep condition until condition is true +// Reset histories, usually before a new game +void Thread::clear() { -void Thread::wait(std::atomic_bool& 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); } -/// Thread::start_searching() wakes up the thread that will start the search - -void Thread::start_searching(bool resume) { +// 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() +} - std::unique_lock lk(mutex); - if (!resume) - searching = true; +// Blocks on the condition variable +// until the thread has finished searching. +void Thread::wait_for_search_finished() { - sleepCondition.notify_one(); + 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() { - WinProcGroup::bindThisThread(idx); + // 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 (!exit) - { - std::unique_lock lk(mutex); + while (true) + { + std::unique_lock lk(mutex); + searching = false; + cv.notify_one(); // Wake up anyone waiting for search finished + cv.wait(lk, [&] { return searching; }); - searching = false; + if (exit) + return; - while (!searching && !exit) - { - sleepCondition.notify_one(); // Wake up any waiting thread - sleepCondition.wait(lk); - } + lk.unlock(); - lk.unlock(); - - if (!exit) - search(); - } + search(); + } } +// 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) { -/// ThreadPool::init() creates and launches requested threads that will go -/// immediately to sleep. We cannot use a constructor because Threads is a -/// static object and we need a fully initialized engine at this point due to -/// allocation of Endgames in the Thread constructor. + if (threads.size() > 0) // destroy any existing thread(s) + { + main()->wait_for_search_finished(); -void ThreadPool::init() { + while (threads.size() > 0) + delete threads.back(), threads.pop_back(); + } - push_back(new MainThread()); - read_uci_options(); -} + if (requested > 0) // create new thread(s) + { + threads.push_back(new MainThread(0)); + while (threads.size() < requested) + threads.push_back(new Thread(threads.size())); + clear(); -/// ThreadPool::exit() terminates threads before the program exits. Cannot be -/// done in destructor because threads must be terminated before deleting any -/// static objects while still in main(). + // Reallocate the hash with the new threadpool size + TT.resize(size_t(Options["Hash"])); -void ThreadPool::exit() { - - while (size()) - delete back(), pop_back(); + // Init thread number dependent search params. + Search::init(); + } } -/// ThreadPool::read_uci_options() updates internal threads parameters from the -/// corresponding UCI options and creates/destroys threads to match requested -/// number. Thread objects are dynamically allocated. - -void ThreadPool::read_uci_options() { - - size_t requested = Options["Threads"]; - - assert(requested > 0); +// Sets threadPool data to initial values +void ThreadPool::clear() { - while (size() < requested) - push_back(new Thread()); + for (Thread* th : threads) + th->clear(); - while (size() > requested) - delete back(), pop_back(); + main()->callsCnt = 0; + main()->bestPreviousScore = VALUE_INFINITE; + main()->bestPreviousAverageScore = VALUE_INFINITE; + main()->previousTimeReduction = 1.0; } -/// ThreadPool::nodes_searched() returns the number of nodes searched - -uint64_t ThreadPool::nodes_searched() const { - - uint64_t nodes = 0; - for (Thread* th : *this) - nodes += th->nodes.load(std::memory_order_relaxed); - return nodes; +// 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::tb_hits() returns the number of TB hits - -uint64_t ThreadPool::tb_hits() const { - - uint64_t hits = 0; - for (Thread* th : *this) - hits += th->tbHits.load(std::memory_order_relaxed); - return hits; +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::start_thinking() wakes up the main thread sleeping in idle_loop() -/// and starts a new search, then returns immediately. - -void ThreadPool::start_thinking(Position& pos, StateListPtr& states, - const Search::LimitsType& limits) { - - main()->wait_for_search_finished(); - - stopOnPonderhit = stop = false; - Search::Limits = limits; - Search::RootMoves rootMoves; +// Start non-main threads - for (const auto& m : MoveList(pos)) - if ( limits.searchmoves.empty() - || std::count(limits.searchmoves.begin(), limits.searchmoves.end(), m)) - rootMoves.push_back(Search::RootMove(m)); +void ThreadPool::start_searching() { - if (!rootMoves.empty()) - Tablebases::filter_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() == NULL. - assert(states.get() || setupStates.get()); - - if (states.get()) - setupStates = std::move(states); // Ownership transfer, states is now empty + for (Thread* th : threads) + if (th != threads.front()) + th->start_searching(); +} - StateInfo tmp = setupStates->back(); - for (Thread* th : Threads) - { - th->nodes = 0; - th->tbHits = 0; - th->rootDepth = DEPTH_ZERO; - th->rootMoves = rootMoves; - th->rootPos.set(pos.fen(), pos.is_chess960(), &setupStates->back(), th); - } +// Wait for non-main threads - setupStates->back() = tmp; // Restore st->previous, cleared by Position::set() +void ThreadPool::wait_for_search_finished() const { - main()->start_searching(); + for (Thread* th : threads) + if (th != threads.front()) + th->wait_for_search_finished(); } + +} // namespace Stockfish