/*
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) 2004-2020 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
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-#include <algorithm> // For std::count
#include <cassert>
+#include <algorithm> // For std::count
#include "movegen.h"
#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 {
+/// Thread constructor launches the thread and waits until it goes to sleep
+/// in idle_loop(). Note that 'searching' and 'exit' should be already set.
- // Helpers to launch a thread after creation and joining before delete. Outside the
- // Thread constructor and destructor because the object must be fully initialized
- // when start_routine (and hence virtual idle_loop) is called and when joining.
+Thread::Thread(size_t n) : idx(n), stdThread(&Thread::idle_loop, this) {
- template<typename T> T* new_thread() {
- std::thread* th = new T;
- *th = std::thread(&T::idle_loop, (T*)th); // Will go to sleep
- return (T*)th;
- }
+ wait_for_search_finished();
+}
- void delete_thread(ThreadBase* th) {
- th->mutex.lock();
- th->exit = true; // Search must be already finished
- th->mutex.unlock();
+/// Thread destructor wakes up the thread in idle_loop() and waits
+/// for its termination. Thread should be already waiting.
- th->notify_one();
- th->join(); // Wait for thread termination
- delete th;
- }
+Thread::~Thread() {
-}
+ assert(!searching);
+ exit = true;
+ start_searching();
+ stdThread.join();
+}
-// ThreadBase::notify_one() wakes up the thread when there is some work to do
-void ThreadBase::notify_one() {
+/// Thread::bestMoveCount(Move move) return best move counter for the given root move
- std::unique_lock<Mutex> lk(mutex);
- sleepCondition.notify_one();
-}
+int Thread::best_move_count(Move move) const {
+ auto rm = std::find(rootMoves.begin() + pvIdx,
+ rootMoves.begin() + pvLast, move);
-// ThreadBase::wait() set the thread to sleep until 'condition' turns true
+ return rm != rootMoves.begin() + pvLast ? rm->bestMoveCount : 0;
+}
-void ThreadBase::wait(std::atomic<bool>& condition) {
- std::unique_lock<Mutex> lk(mutex);
- sleepCondition.wait(lk, [&]{ return bool(condition); });
-}
+/// Thread::clear() reset histories, usually before a new game
+void Thread::clear() {
-// ThreadBase::wait_while() set the thread to sleep until 'condition' turns false
-void ThreadBase::wait_while(std::atomic<bool>& condition) {
+ counterMoves.fill(MOVE_NONE);
+ mainHistory.fill(0);
+ lowPlyHistory.fill(0);
+ captureHistory.fill(0);
- std::unique_lock<Mutex> lk(mutex);
- sleepCondition.wait(lk, [&]{ return !condition; });
+ for (bool inCheck : { false, true })
+ for (StatsType c : { NoCaptures, Captures })
+ {
+ for (auto& to : continuationHistory[inCheck][c])
+ for (auto& h : to)
+ h->fill(0);
+ continuationHistory[inCheck][c][NO_PIECE][0]->fill(Search::CounterMovePruneThreshold - 1);
+ }
}
-// Thread constructor makes some init but does not launch any execution thread,
-// which will be started only when the constructor returns.
+/// Thread::start_searching() wakes up the thread that will start the search
-Thread::Thread() {
+void Thread::start_searching() {
- searching = false;
- maxPly = 0;
- history.clear();
- counterMoves.clear();
- idx = Threads.size(); // Starts from 0
+ std::lock_guard<std::mutex> lk(mutex);
+ searching = true;
+ cv.notify_one(); // Wake up the thread in idle_loop()
}
-// 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() {
+/// Thread::wait_for_search_finished() blocks on the condition variable
+/// until the thread has finished searching.
- while (!exit)
- {
- std::unique_lock<Mutex> lk(mutex);
-
- if (!exit)
- sleepCondition.wait_for(lk, std::chrono::milliseconds(run ? Resolution : INT_MAX));
-
- lk.unlock();
+void Thread::wait_for_search_finished() {
- if (!exit && run)
- check_time();
- }
+ std::unique_lock<std::mutex> 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)
+ // 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 (true)
{
- std::unique_lock<Mutex> lk(mutex);
+ std::unique_lock<std::mutex> lk(mutex);
+ searching = false;
+ cv.notify_one(); // Wake up anyone waiting for search finished
+ cv.wait(lk, [&]{ return searching; });
- while (!searching && !exit)
- sleepCondition.wait(lk);
+ if (exit)
+ return;
lk.unlock();
- if (!exit && searching)
- search();
+ search();
}
}
+/// ThreadPool::set() 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.
-// 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 ThreadPool::set(size_t requested) {
-void MainThread::idle_loop() {
+ if (size() > 0) { // destroy any existing thread(s)
+ main()->wait_for_search_finished();
- while (!exit)
- {
- std::unique_lock<Mutex> lk(mutex);
+ while (size() > 0)
+ delete back(), pop_back();
+ }
- thinking = false;
+ if (requested > 0) { // create new thread(s)
+ push_back(new MainThread(0));
- while (!thinking && !exit)
- {
- sleepCondition.notify_one(); // Wake up the UI thread if needed
- sleepCondition.wait(lk);
- }
+ while (size() < requested)
+ push_back(new Thread(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
-
-void MainThread::join() {
+/// ThreadPool::clear() sets threadPool data to initial values
- std::unique_lock<Mutex> lk(mutex);
- sleepCondition.wait(lk, [&]{ return !thinking; });
-}
-
-
-// ThreadPool::init() is called at startup to create and launch 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.
+void ThreadPool::clear() {
-void ThreadPool::init() {
+ for (Thread* th : *this)
+ th->clear();
- timer = new_thread<TimerThread>();
- push_back(new_thread<MainThread>());
- read_uci_options();
+ main()->callsCnt = 0;
+ main()->bestPreviousScore = VALUE_INFINITE;
+ main()->previousTimeReduction = 1.0;
}
-// ThreadPool::exit() terminates the threads before the program exits. Cannot be
-// done in destructor because threads must be terminated before freeing us.
-
-void ThreadPool::exit() {
-
- delete_thread(timer); // As first because check_time() accesses threads data
- timer = nullptr;
+/// 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.
- for (Thread* th : *this)
- delete_thread(th);
-
- clear(); // Get rid of stale pointers
-}
+void ThreadPool::start_thinking(Position& pos, StateListPtr& states,
+ const Search::LimitsType& limits, bool ponderMode) {
+ main()->wait_for_search_finished();
-// 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.
+ main()->stopOnPonderhit = stop = false;
+ increaseDepth = true;
+ main()->ponder = ponderMode;
+ Search::Limits = limits;
+ Search::RootMoves rootMoves;
-void ThreadPool::read_uci_options() {
+ for (const auto& m : MoveList<LEGAL>(pos))
+ if ( limits.searchmoves.empty()
+ || std::count(limits.searchmoves.begin(), limits.searchmoves.end(), m))
+ rootMoves.emplace_back(m);
- size_t requested = Options["Threads"];
+ if (!rootMoves.empty())
+ Tablebases::rank_root_moves(pos, rootMoves);
- assert(requested > 0);
+ // 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());
- while (size() < requested)
- push_back(new_thread<Thread>());
+ if (states.get())
+ setupStates = std::move(states); // Ownership transfer, states is now empty
- while (size() > requested)
+ // 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 : *this)
{
- delete_thread(back());
- pop_back();
+ 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();
}
-}
-
-// ThreadPool::nodes_searched() returns the number of nodes searched
-
-int64_t ThreadPool::nodes_searched() {
+ main()->start_searching();
+}
- int64_t nodes = 0;
- for (Thread *th : *this)
- nodes += th->rootPos.nodes_searched();
- return nodes;
+Thread* ThreadPool::get_best_thread() const {
+
+ Thread* bestThread = front();
+ std::map<Move, int64_t> votes;
+ Value minScore = VALUE_NONE;
+
+ // Find minimum score of all threads
+ for (Thread* th: *this)
+ minScore = std::min(minScore, th->rootMoves[0].score);
+
+ // Vote according to score and depth, and select the best thread
+ for (Thread* th : *this)
+ {
+ votes[th->rootMoves[0].pv[0]] +=
+ (th->rootMoves[0].score - minScore + 14) * int(th->completedDepth);
+
+ if (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]]))
+ bestThread = th;
+ }
+
+ return bestThread;
}
-// ThreadPool::start_thinking() wakes up the main thread sleeping in
-// MainThread::idle_loop() and starts a new search, then returns immediately.
+/// Start non-main threads
+
+void ThreadPool::start_searching() {
-void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits,
- StateStackPtr& states) {
- main()->join();
+ for (Thread* th : *this)
+ if (th != front())
+ th->start_searching();
+}
- 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());
- }
+/// Wait for non-main threads
- for (const auto& m : MoveList<LEGAL>(pos))
- if ( limits.searchmoves.empty()
- || std::count(limits.searchmoves.begin(), limits.searchmoves.end(), m))
- main()->rootMoves.push_back(RootMove(m));
+void ThreadPool::wait_for_search_finished() const {
- main()->thinking = true;
- main()->notify_one(); // Wake up main thread: 'thinking' must be already set
+ for (Thread* th : *this)
+ if (th != front())
+ th->wait_for_search_finished();
}
projects / stockfish / blobdiff