/*
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
+ 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
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-#include <algorithm> // For std::count
-#include <cassert>
+#include "thread.h"
+#include <algorithm>
+#include <cassert>
+#include <cstdlib>
+#include <deque>
+#include <initializer_list>
+#include <map>
+#include <memory>
+#include <utility>
+
+#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"
+
+namespace Stockfish {
ThreadPool Threads; // Global object
-/// Thread constructor launches the thread and waits until it goes to sleep
-/// in idle_loop(). Note that 'searching' and 'exit' should be alredy set.
+// Thread 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) {
}
-/// Thread destructor wakes up the thread in idle_loop() and waits
-/// for its termination. Thread should be already waiting.
+// Thread destructor wakes up the thread in idle_loop() and waits
+// for its termination. Thread should be already waiting.
Thread::~Thread() {
}
-/// Thread::clear() reset histories, usually before a new game
+// Thread::clear() reset histories, usually before a new game
void Thread::clear() {
mainHistory.fill(0);
captureHistory.fill(0);
- for (auto& to : contHistory)
- for (auto& h : to)
- h.fill(0);
-
- contHistory[NO_PIECE][0].fill(Search::CounterMovePruneThreshold - 1);
+ 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() {
+// Thread::start_searching() wakes up the thread that will start the search
- std::lock_guard<Mutex> lk(mutex);
+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::wait_for_search_finished() blocks on the condition variable
-/// until the thread has finished searching.
+// Thread::wait_for_search_finished() blocks on the condition variable
+// until the thread has finished searching.
void Thread::wait_for_search_finished() {
- std::unique_lock<Mutex> lk(mutex);
+ std::unique_lock<std::mutex> lk(mutex);
cv.wait(lk, [&]{ return !searching; });
}
-/// Thread::idle_loop() is where the thread is parked, blocked on the
-/// condition variable, 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() {
// 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
+ // just check if running threads are below a threshold, in this case, all this
// NUMA machinery is not needed.
- if (Options["Threads"] >= 8)
+ 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; });
}
}
-/// ThreadPool::set() creates/destroys threads to match the requested number.
-/// Created and launced threads wil go immediately to sleep in idle_loop.
-/// Upon resizing, threads are recreated to allow for binding if necessary.
+// 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.
void ThreadPool::set(size_t requested) {
- if (size() > 0) { // destroy any existing thread(s)
+ if (threads.size() > 0) // destroy any existing thread(s)
+ {
main()->wait_for_search_finished();
- while (size() > 0)
- delete back(), pop_back();
+ while (threads.size() > 0)
+ delete threads.back(), threads.pop_back();
}
- if (requested > 0) { // create new thread(s)
- push_back(new MainThread(0));
+ if (requested > 0) // create new thread(s)
+ {
+ threads.push_back(new MainThread(0));
- while (size() < requested)
- push_back(new Thread(size()));
+ while (threads.size() < requested)
+ threads.push_back(new Thread(threads.size()));
clear();
+
+ // Reallocate the hash with the new threadpool size
+ TT.resize(size_t(Options["Hash"]));
+
+ // Init thread number dependent search params.
+ Search::init();
}
}
-/// ThreadPool::clear() sets threadPool data to initial values.
+
+// ThreadPool::clear() sets threadPool data to initial values
void ThreadPool::clear() {
- for (Thread* th : *this)
+ for (Thread* th : threads)
th->clear();
main()->callsCnt = 0;
- main()->previousScore = VALUE_INFINITE;
- main()->previousTimeReduction = 1;
+ main()->bestPreviousScore = VALUE_INFINITE;
+ main()->bestPreviousAverageScore = 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::start_thinking() 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();
- stopOnPonderhit = stop = false;
- ponder = ponderMode;
+ main()->stopOnPonderhit = stop = false;
+ increaseDepth = true;
+ main()->ponder = ponderMode;
Search::Limits = limits;
Search::RootMoves rootMoves;
rootMoves.emplace_back(m);
if (!rootMoves.empty())
- Tablebases::filter_root_moves(pos, rootMoves);
+ 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() == NULL.
+ // and call 'go' again without setting a new position states.get() == nullptr.
assert(states.get() || setupStates.get());
if (states.get())
// 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();
-
- for (Thread* th : *this)
+ // 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 = 0;
- th->rootDepth = th->completedDepth = DEPTH_ZERO;
+ 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(), &setupStates->back(), th);
- th->nmp_ply = 0;
- th->pair = -1;
+ 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());
}
- setupStates->back() = tmp;
-
main()->start_searching();
}
+
+Thread* ThreadPool::get_best_thread() const {
+
+ Thread* bestThread = threads.front();
+ std::map<Move, int64_t> 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 (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;
+}
+
+
+// Start non-main threads
+
+void ThreadPool::start_searching() {
+
+ for (Thread* th : threads)
+ if (th != threads.front())
+ th->start_searching();
+}
+
+
+// Wait for non-main threads
+
+void ThreadPool::wait_for_search_finished() const {
+
+ for (Thread* th : threads)
+ if (th != threads.front())
+ th->wait_for_search_finished();
+}
+
+} // namespace Stockfish
projects / stockfish / blobdiff