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) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
#include "search.h"
#include "thread.h"
#include "uci.h"
-
-using namespace Search;
+#include "syzygy/tbprobe.h"
ThreadPool Threads; // Global object
-// Thread constructor makes some init and launches the thread that will go to
-// sleep in idle_loop().
+/// Thread constructor launches the thread and then waits until it goes to sleep
+/// in idle_loop().
Thread::Thread() {
- searching = true; // Avoid a race with start_thinking()
- exit = resetCalls = false;
+ resetCalls = exit = false;
maxPly = callsCnt = 0;
- history.clear();
- counterMoves.clear();
- idx = Threads.size(); // Starts from 0
- std::thread::operator=(std::thread(&Thread::idle_loop, this));
+ tbHits = 0;
+ idx = Threads.size(); // Start from 0
+
+ std::unique_lock<Mutex> lk(mutex);
+ searching = true;
+ nativeThread = std::thread(&Thread::idle_loop, this);
+ sleepCondition.wait(lk, [&]{ return !searching; });
}
-// Thread destructor waits for thread termination before deleting
+/// Thread destructor waits for thread termination before returning
Thread::~Thread() {
mutex.lock();
- exit = true; // Search must be already finished
+ exit = true;
+ sleepCondition.notify_one();
mutex.unlock();
-
- notify_one();
- std::thread::join(); // Wait for thread termination
+ nativeThread.join();
}
-// Thread::join() waits for the thread to finish searching
-void Thread::join() {
+/// Thread::wait_for_search_finished() waits on sleep condition
+/// until not searching
+
+void Thread::wait_for_search_finished() {
std::unique_lock<Mutex> lk(mutex);
sleepCondition.wait(lk, [&]{ return !searching; });
}
-// Thread::notify_one() wakes up the thread when there is some work to do
+/// Thread::wait() waits on sleep condition until condition is true
-void Thread::notify_one() {
+void Thread::wait(std::atomic_bool& condition) {
std::unique_lock<Mutex> lk(mutex);
- sleepCondition.notify_one();
+ sleepCondition.wait(lk, [&]{ return bool(condition); });
}
-// Thread::wait() set the thread to sleep until 'condition' turns true
+/// Thread::start_searching() wakes up the thread that will start the search
-void Thread::wait(std::atomic_bool& condition) {
+void Thread::start_searching(bool resume) {
std::unique_lock<Mutex> lk(mutex);
- sleepCondition.wait(lk, [&]{ return bool(condition); });
+
+ if (!resume)
+ searching = true;
+
+ sleepCondition.notify_one();
}
-// 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 when it has no work to do
void Thread::idle_loop() {
+ WinProcGroup::bindThisThread(idx);
+
while (!exit)
{
std::unique_lock<Mutex> lk(mutex);
while (!searching && !exit)
{
- sleepCondition.notify_one(); // Wake up main thread if needed
+ sleepCondition.notify_one(); // Wake up any waiting thread
sleepCondition.wait(lk);
}
lk.unlock();
- if (!exit && searching)
+ if (!exit)
search();
}
}
-// 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.
+/// 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.
void ThreadPool::init() {
- push_back(new MainThread);
+ push_back(new MainThread());
read_uci_options();
}
-// ThreadPool::exit() terminates the threads before the program exits. Cannot be
-// done in destructor because threads must be terminated before freeing us.
+/// 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().
void ThreadPool::exit() {
- for (Thread* th : *this)
- delete th;
-
- clear(); // Get rid of stale pointers
+ while (size())
+ delete back(), pop_back();
}
-// 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.
+/// 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"];
+ size_t requested = Options["Threads"];
assert(requested > 0);
while (size() < requested)
- push_back(new Thread);
+ push_back(new Thread());
while (size() > requested)
- {
- delete back();
- pop_back();
- }
+ delete back(), pop_back();
}
-// ThreadPool::nodes_searched() returns the number of nodes searched
+/// ThreadPool::nodes_searched() returns the number of nodes searched
-int64_t ThreadPool::nodes_searched() {
+uint64_t ThreadPool::nodes_searched() const {
- int64_t nodes = 0;
- for (Thread *th : *this)
+ uint64_t nodes = 0;
+ for (Thread* th : *this)
nodes += th->rootPos.nodes_searched();
return nodes;
}
-// ThreadPool::start_thinking() wakes up the main thread sleeping in
-// MainThread::idle_loop() and starts a new search, then returns immediately.
+/// ThreadPool::tb_hits() returns the number of TB hits
-void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits,
- StateStackPtr& states) {
- for (Thread* th : Threads)
- th->join();
+uint64_t ThreadPool::tb_hits() const {
- Signals.stopOnPonderhit = Signals.firstRootMove = false;
- Signals.stop = Signals.failedLowAtRoot = false;
+ uint64_t hits = 0;
+ for (Thread* th : *this)
+ hits += th->tbHits;
+ return hits;
+}
- 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());
- }
+
+/// 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();
+
+ Search::Signals.stopOnPonderhit = Search::Signals.stop = false;
+ 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))
- main()->rootMoves.push_back(RootMove(m));
+ rootMoves.push_back(Search::RootMove(m));
+
+ 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
+
+ StateInfo tmp = setupStates->back();
+
+ for (Thread* th : Threads)
+ {
+ th->maxPly = 0;
+ th->tbHits = 0;
+ th->rootDepth = DEPTH_ZERO;
+ th->rootMoves = rootMoves;
+ th->rootPos.set(pos.fen(), pos.is_chess960(), &setupStates->back(), th);
+ }
+
+ setupStates->back() = tmp; // Restore st->previous, cleared by Position::set()
- main()->searching = true;
- main()->notify_one(); // Wake up main thread: 'searching' must be already set
+ main()->start_searching();
}
projects / stockfish / blobdiff