267 lines
7.5 KiB
C++
267 lines
7.5 KiB
C++
/*
|
|
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
|
|
Copyright (C) 2004-2021 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
|
|
the Free Software Foundation, either version 3 of the License, or
|
|
(at your option) any later version.
|
|
|
|
Stockfish is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#include <cassert>
|
|
|
|
#include <algorithm> // For std::count
|
|
#include "movegen.h"
|
|
#include "search.h"
|
|
#include "thread.h"
|
|
#include "uci.h"
|
|
#include "syzygy/tbprobe.h"
|
|
#include "tt.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 already set.
|
|
|
|
Thread::Thread(size_t n) : idx(n), stdThread(&Thread::idle_loop, this) {
|
|
|
|
wait_for_search_finished();
|
|
}
|
|
|
|
|
|
/// Thread destructor wakes up the thread in idle_loop() and waits
|
|
/// for its termination. Thread should be already waiting.
|
|
|
|
Thread::~Thread() {
|
|
|
|
assert(!searching);
|
|
|
|
exit = true;
|
|
start_searching();
|
|
stdThread.join();
|
|
}
|
|
|
|
|
|
/// Thread::clear() reset histories, usually before a new game
|
|
|
|
void Thread::clear() {
|
|
|
|
counterMoves.fill(MOVE_NONE);
|
|
mainHistory.fill(0);
|
|
lowPlyHistory.fill(0);
|
|
captureHistory.fill(0);
|
|
|
|
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::start_searching() wakes up the thread that will start the search
|
|
|
|
void Thread::start_searching() {
|
|
|
|
std::lock_guard<std::mutex> lk(mutex);
|
|
searching = true;
|
|
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.
|
|
|
|
void Thread::wait_for_search_finished() {
|
|
|
|
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.
|
|
|
|
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
|
|
// NUMA machinery is not needed.
|
|
if (Options["Threads"] > 8)
|
|
WinProcGroup::bindThisThread(idx);
|
|
|
|
while (true)
|
|
{
|
|
std::unique_lock<std::mutex> lk(mutex);
|
|
searching = false;
|
|
cv.notify_one(); // Wake up anyone waiting for search finished
|
|
cv.wait(lk, [&]{ return searching; });
|
|
|
|
if (exit)
|
|
return;
|
|
|
|
lk.unlock();
|
|
|
|
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.
|
|
|
|
void ThreadPool::set(size_t requested) {
|
|
|
|
if (size() > 0) // destroy any existing thread(s)
|
|
{
|
|
main()->wait_for_search_finished();
|
|
|
|
while (size() > 0)
|
|
delete back(), pop_back();
|
|
}
|
|
|
|
if (requested > 0) // create new thread(s)
|
|
{
|
|
push_back(new MainThread(0));
|
|
|
|
while (size() < requested)
|
|
push_back(new Thread(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
|
|
|
|
void ThreadPool::clear() {
|
|
|
|
for (Thread* th : *this)
|
|
th->clear();
|
|
|
|
main()->callsCnt = 0;
|
|
main()->bestPreviousScore = 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.
|
|
|
|
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<LEGAL>(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() == NULL.
|
|
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 : *this)
|
|
{
|
|
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();
|
|
}
|
|
|
|
main()->start_searching();
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
|
|
/// Start non-main threads
|
|
|
|
void ThreadPool::start_searching() {
|
|
|
|
for (Thread* th : *this)
|
|
if (th != front())
|
|
th->start_searching();
|
|
}
|
|
|
|
|
|
/// Wait for non-main threads
|
|
|
|
void ThreadPool::wait_for_search_finished() const {
|
|
|
|
for (Thread* th : *this)
|
|
if (th != front())
|
|
th->wait_for_search_finished();
|
|
}
|
|
|
|
} // namespace Stockfish
|