X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fthread.cpp;h=1336ce077cdeac25abb6fc2811221db3aee1dc38;hp=49a598f1d41da631a8416794686af24ff8f77079;hb=00d9e9fd283b31e63389af091b158dbc3fedfc0e;hpb=2617aa415e94eeccf4a7e77aec0f55cebb351366
diff --git a/src/thread.cpp b/src/thread.cpp
index 49a598f1..eb64f7ee 100644
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -1,7 +1,7 @@
/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, 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
@@ -17,443 +17,244 @@
along with this program. If not, see .
*/
-#include
+#include // For std::count
+#include
+#include "movegen.h"
+#include "search.h"
#include "thread.h"
-#include "ucioption.h"
+#include "uci.h"
-ThreadsManager Threads; // Global object definition
+using namespace Search;
-namespace { extern "C" {
+ThreadPool Threads; // Global object
- // start_routine() is the C function which is called when a new thread
- // is launched. It simply calls idle_loop() of the supplied thread. The
- // last thread is dedicated to I/O and so runs in listener_loop().
+extern void check_time();
-#if defined(_MSC_VER)
- DWORD WINAPI start_routine(LPVOID thread) {
-#else
- void* start_routine(void* thread) {
-#endif
+namespace {
- if (((Thread*)thread)->threadID == MAX_THREADS)
- ((Thread*)thread)->listener_loop();
- else
- ((Thread*)thread)->idle_loop(NULL);
+ // Helpers to launch a thread after creation and joining before delete. Must be
+ // outside Thread c'tor and d'tor because the object must be fully initialized
+ // when start_routine (and hence virtual idle_loop) is called and when joining.
- return 0;
- }
-
-} }
+ template T* new_thread() {
+ std::thread* th = new T;
+ *th = std::thread(&T::idle_loop, (T*)th); // Will go to sleep
+ return (T*)th;
+ }
+ void delete_thread(ThreadBase* th) {
-// wake_up() wakes up the thread, normally at the beginning of the search or,
-// if "sleeping threads" is used, when there is some work to do.
+ th->mutex.lock();
+ th->exit = true; // Search must be already finished
+ th->mutex.unlock();
-void Thread::wake_up() {
+ th->notify_one();
+ th->join(); // Wait for thread termination
+ delete th;
+ }
- lock_grab(&sleepLock);
- cond_signal(&sleepCond);
- lock_release(&sleepLock);
}
-// cutoff_occurred() checks whether a beta cutoff has occurred in the current
-// active split point, or in some ancestor of the split point.
+// ThreadBase::notify_one() wakes up the thread when there is some work to do
-bool Thread::cutoff_occurred() const {
+void ThreadBase::notify_one() {
- for (SplitPoint* sp = splitPoint; sp; sp = sp->parent)
- if (sp->is_betaCutoff)
- return true;
- return false;
+ std::unique_lock lk(mutex);
+ sleepCondition.notify_one();
}
-// is_available_to() checks whether the thread is available to help the thread with
-// threadID "master" at a split point. An obvious requirement is that thread must be
-// idle. With more than two threads, this is not by itself sufficient: If the thread
-// is the master of some active split point, it is only available as a slave to the
-// threads which are busy searching the split point at the top of "slave"'s split
-// point stack (the "helpful master concept" in YBWC terminology).
-
-bool Thread::is_available_to(int master) const {
-
- if (is_searching)
- return false;
+// ThreadBase::wait() set the thread to sleep until 'condition' turns true
- // Make a local copy to be sure doesn't become zero under our feet while
- // testing next condition and so leading to an out of bound access.
- int localActiveSplitPoints = activeSplitPoints;
+void ThreadBase::wait(std::atomic& condition) {
- // No active split points means that the thread is available as a slave for any
- // other thread otherwise apply the "helpful master" concept if possible.
- if ( !localActiveSplitPoints
- || splitPoints[localActiveSplitPoints - 1].is_slave[master])
- return true;
-
- return false;
+ std::unique_lock lk(mutex);
+ sleepCondition.wait(lk, [&]{ return bool(condition); });
}
-// read_uci_options() updates number of active threads and other internal
-// parameters according to the UCI options values. It is called before
-// to start a new search.
-
-void ThreadsManager::read_uci_options() {
-
- maxThreadsPerSplitPoint = Options["Maximum Number of Threads per Split Point"].value();
- minimumSplitDepth = Options["Minimum Split Depth"].value() * ONE_PLY;
- useSleepingThreads = Options["Use Sleeping Threads"].value();
+// ThreadBase::wait_while() set the thread to sleep until 'condition' turns false
+void ThreadBase::wait_while(std::atomic& condition) {
- set_size(Options["Threads"].value());
+ std::unique_lock lk(mutex);
+ sleepCondition.wait(lk, [&]{ return !condition; });
}
-// set_size() changes the number of active threads and raises do_sleep flag for
-// all the unused threads that will go immediately to sleep.
+// Thread c'tor makes some init but does not launch any execution thread that
+// will be started only when c'tor returns.
-void ThreadsManager::set_size(int cnt) {
+Thread::Thread() {
- assert(cnt > 0 && cnt <= MAX_THREADS);
-
- activeThreads = cnt;
-
- for (int i = 0; i < MAX_THREADS; i++)
- if (i < activeThreads)
- {
- // Dynamically allocate pawn and material hash tables according to the
- // number of active threads. This avoids preallocating memory for all
- // possible threads if only few are used as, for instance, on mobile
- // devices where memory is scarce and allocating for MAX_THREADS could
- // even result in a crash.
- threads[i].pawnTable.init();
- threads[i].materialTable.init();
-
- threads[i].do_sleep = false;
- }
- else
- threads[i].do_sleep = true;
+ searching = false;
+ maxPly = 0;
+ history.clear();
+ counterMoves.clear();
+ idx = Threads.size(); // Starts from 0
}
-// init() is called during startup. Initializes locks and condition variables
-// and launches all threads sending them immediately to sleep.
+// 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 ThreadsManager::init() {
+void TimerThread::idle_loop() {
- // Initialize sleep condition used to block waiting for GUI input
- cond_init(&sleepCond);
-
- // Initialize threads lock, used when allocating slaves during splitting
- lock_init(&threadsLock);
-
- // Initialize sleep and split point locks
- for (int i = 0; i <= MAX_THREADS; i++)
+ while (!exit)
{
- lock_init(&threads[i].sleepLock);
- cond_init(&threads[i].sleepCond);
-
- for (int j = 0; j < MAX_ACTIVE_SPLIT_POINTS; j++)
- lock_init(&(threads[i].splitPoints[j].lock));
- }
-
- // Initialize main thread's associated data
- threads[0].is_searching = true;
- threads[0].threadID = 0;
- set_size(1); // This makes all the threads but the main to go to sleep
+ std::unique_lock lk(mutex);
- // Create and launch all the threads but the main that is already running,
- // threads will go immediately to sleep.
- for (int i = 1; i <= MAX_THREADS; i++)
- {
- threads[i].is_searching = false;
- threads[i].threadID = i;
+ if (!exit)
+ sleepCondition.wait_for(lk, std::chrono::milliseconds(run ? Resolution : INT_MAX));
-#if defined(_MSC_VER)
- threads[i].handle = CreateThread(NULL, 0, start_routine, (LPVOID)&threads[i], 0, NULL);
- bool ok = (threads[i].handle != NULL);
-#else
- bool ok = (pthread_create(&threads[i].handle, NULL, start_routine, (void*)&threads[i]) == 0);
-#endif
+ lk.unlock();
- if (!ok)
- {
- std::cerr << "Failed to create thread number " << i << std::endl;
- ::exit(EXIT_FAILURE);
- }
+ if (!exit && run)
+ check_time();
}
}
-// exit() is called to cleanly terminate the threads when the program finishes
+// Thread::idle_loop() is where the thread is parked when it has no work to do
-void ThreadsManager::exit() {
+void Thread::idle_loop() {
- for (int i = 0; i <= MAX_THREADS; i++)
+ while (!exit)
{
- if (i != 0)
- {
- threads[i].do_terminate = true;
- threads[i].wake_up();
-
- // Wait for slave termination
-#if defined(_MSC_VER)
- WaitForSingleObject(threads[i].handle, 0);
- CloseHandle(threads[i].handle);
-#else
- pthread_join(threads[i].handle, NULL);
-#endif
- }
+ std::unique_lock lk(mutex);
- // Now we can safely destroy locks and wait conditions
- lock_destroy(&threads[i].sleepLock);
- cond_destroy(&threads[i].sleepCond);
+ while (!searching && !exit)
+ sleepCondition.wait(lk);
- for (int j = 0; j < MAX_ACTIVE_SPLIT_POINTS; j++)
- lock_destroy(&(threads[i].splitPoints[j].lock));
- }
+ lk.unlock();
- lock_destroy(&threadsLock);
- cond_destroy(&sleepCond);
+ if (!exit && searching)
+ search();
+ }
}
-// available_slave_exists() tries to find an idle thread which is available as
-// a slave for the thread with threadID "master".
-
-bool ThreadsManager::available_slave_exists(int master) const {
-
- assert(master >= 0 && master < activeThreads);
+// 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.
- for (int i = 0; i < activeThreads; i++)
- if (i != master && threads[i].is_available_to(master))
- return true;
+void MainThread::idle_loop() {
- return false;
-}
+ while (!exit)
+ {
+ std::unique_lock lk(mutex);
+ thinking = false;
-// split() does the actual work of distributing the work at a node between
-// several available threads. If it does not succeed in splitting the
-// node (because no idle threads are available, or because we have no unused
-// split point objects), the function immediately returns. If splitting is
-// possible, a SplitPoint object is initialized with all the data that must be
-// copied to the helper threads and we tell our helper threads that they have
-// been assigned work. This will cause them to instantly leave their idle loops and
-// call search().When all threads have returned from search() then split() returns.
-
-template
-Value ThreadsManager::split(Position& pos, SearchStack* ss, Value alpha, Value beta,
- Value bestValue, Depth depth, Move threatMove,
- int moveCount, MovePicker* mp, int nodeType) {
- assert(pos.pos_is_ok());
- assert(bestValue >= -VALUE_INFINITE);
- assert(bestValue <= alpha);
- assert(alpha < beta);
- assert(beta <= VALUE_INFINITE);
- assert(depth > DEPTH_ZERO);
- assert(pos.thread() >= 0 && pos.thread() < activeThreads);
- assert(activeThreads > 1);
-
- int i, master = pos.thread();
- Thread& masterThread = threads[master];
-
- // If we already have too many active split points, don't split
- if (masterThread.activeSplitPoints >= MAX_ACTIVE_SPLIT_POINTS)
- return bestValue;
-
- // Pick the next available split point object from the split point stack
- SplitPoint* sp = masterThread.splitPoints + masterThread.activeSplitPoints;
-
- // Initialize the split point object
- sp->parent = masterThread.splitPoint;
- sp->master = master;
- sp->is_betaCutoff = false;
- sp->depth = depth;
- sp->threatMove = threatMove;
- sp->alpha = alpha;
- sp->beta = beta;
- sp->nodeType = nodeType;
- sp->bestValue = bestValue;
- sp->mp = mp;
- sp->moveCount = moveCount;
- sp->pos = &pos;
- sp->nodes = 0;
- sp->ss = ss;
- for (i = 0; i < activeThreads; i++)
- sp->is_slave[i] = false;
-
- // If we are here it means we are not available
- assert(masterThread.is_searching);
-
- int workersCnt = 1; // At least the master is included
-
- // Try to allocate available threads and ask them to start searching setting
- // the state to Thread::WORKISWAITING, this must be done under lock protection
- // to avoid concurrent allocation of the same slave by another master.
- lock_grab(&threadsLock);
-
- for (i = 0; !Fake && i < activeThreads && workersCnt < maxThreadsPerSplitPoint; i++)
- if (i != master && threads[i].is_available_to(master))
+ while (!thinking && !exit)
{
- workersCnt++;
- sp->is_slave[i] = true;
- threads[i].splitPoint = sp;
-
- // This makes the slave to exit from idle_loop()
- threads[i].is_searching = true;
-
- if (useSleepingThreads)
- threads[i].wake_up();
+ sleepCondition.notify_one(); // Wake up the UI thread if needed
+ sleepCondition.wait(lk);
}
- lock_release(&threadsLock);
-
- // We failed to allocate even one slave, return
- if (!Fake && workersCnt == 1)
- return bestValue;
-
- masterThread.splitPoint = sp;
- masterThread.activeSplitPoints++;
-
- // Everything is set up. The master thread enters the idle loop, from which
- // it will instantly launch a search, because its is_searching flag is set.
- // We pass the split point as a parameter to the idle loop, which means that
- // the thread will return from the idle loop when all slaves have finished
- // their work at this split point.
- masterThread.idle_loop(sp);
-
- // In helpful master concept a master can help only a sub-tree, and
- // because here is all finished is not possible master is booked.
- assert(!masterThread.is_searching);
-
- // We have returned from the idle loop, which means that all threads are
- // finished. Note that changing state and decreasing activeSplitPoints is done
- // under lock protection to avoid a race with Thread::is_available_to().
- lock_grab(&threadsLock);
-
- masterThread.is_searching = true;
- masterThread.activeSplitPoints--;
+ lk.unlock();
- lock_release(&threadsLock);
-
- masterThread.splitPoint = sp->parent;
- pos.set_nodes_searched(pos.nodes_searched() + sp->nodes);
-
- return sp->bestValue;
+ if (!exit)
+ think();
+ }
}
-// Explicit template instantiations
-template Value ThreadsManager::split(Position&, SearchStack*, Value, Value, Value, Depth, Move, int, MovePicker*, int);
-template Value ThreadsManager::split(Position&, SearchStack*, Value, Value, Value, Depth, Move, int, MovePicker*, int);
+// MainThread::join() waits for main thread to finish thinking
-// Thread::listner_loop() is where the last thread, used for IO, waits for input.
-// Input is read in sync with main thread (that blocks) when is_searching is set
-// to false, otherwise IO thread reads any input asynchronously and processes
-// the input line calling do_uci_async_cmd().
+void MainThread::join() {
-void Thread::listener_loop() {
+ std::unique_lock lk(mutex);
+ sleepCondition.wait(lk, [&]{ return !thinking; });
+}
- std::string cmd;
- while (true)
- {
- lock_grab(&sleepLock);
+// ThreadPool::init() is called at startup to create and launch requested threads,
+// that will go immediately to sleep. We cannot use a c'tor because Threads is a
+// static object and we need a fully initialized engine at this point due to
+// allocation of Endgames in Thread c'tor.
- Threads.inputLine = cmd;
- do_sleep = !is_searching;
+void ThreadPool::init() {
- // Here the thread is parked in sync mode after a line has been read
- while (do_sleep && !do_terminate) // Catches spurious wake ups
- {
- cond_signal(&Threads.sleepCond); // Wake up main thread
- cond_wait(&sleepCond, &sleepLock); // Sleep here
- }
-
- lock_release(&sleepLock);
+ timer = new_thread();
+ push_back(new_thread());
+ read_uci_options();
+}
- if (do_terminate)
- return;
- if (!std::getline(std::cin, cmd)) // Block waiting for input
- cmd = "quit";
+// ThreadPool::exit() terminates the threads before the program exits. Cannot be
+// done in d'tor because threads must be terminated before freeing us.
- lock_grab(&sleepLock);
+void ThreadPool::exit() {
- // If we are in async mode then process the command now
- if (is_searching)
- {
- // Command "quit" is the last one received by the GUI, so park the
- // thread waiting for exiting.
- if (cmd == "quit")
- is_searching = false;
+ delete_thread(timer); // As first because check_time() accesses threads data
+ timer = nullptr;
- Threads.do_uci_async_cmd(cmd);
- cmd = ""; // Input has been consumed
- }
+ for (Thread* th : *this)
+ delete_thread(th);
- lock_release(&sleepLock);
- }
+ clear(); // Get rid of stale pointers
}
-// ThreadsManager::getline() is used by main thread to block and wait for input,
-// the behaviour mimics std::getline().
+// 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.
-void ThreadsManager::getline(std::string& cmd) {
+void ThreadPool::read_uci_options() {
- Thread& listener = threads[MAX_THREADS];
+ size_t requested = Options["Threads"];
- lock_grab(&listener.sleepLock);
+ assert(requested > 0);
- listener.is_searching = false; // Set sync mode
+ while (size() < requested)
+ push_back(new_thread());
- // If there is already some input to grab then skip without to wake up the
- // listener. This can happen if after we send the "bestmove", the GUI sends
- // a command that the listener buffers in inputLine before going to sleep.
- if (inputLine.empty())
+ while (size() > requested)
{
- listener.do_sleep = false;
- cond_signal(&listener.sleepCond); // Wake up listener thread
-
- while (!listener.do_sleep)
- cond_wait(&sleepCond, &listener.sleepLock); // Wait for input
+ delete_thread(back());
+ pop_back();
}
-
- cmd = inputLine;
- inputLine = ""; // Input has been consumed
-
- lock_release(&listener.sleepLock);
}
-// ThreadsManager::start_listener() is called at the beginning of the search to
-// swith from sync behaviour (default) to async and so be able to read from UCI
-// while other threads are searching. This avoids main thread polling for input.
-
-void ThreadsManager::start_listener() {
+// ThreadPool::nodes_searched() returns the number of nodes searched
- Thread& listener = threads[MAX_THREADS];
+int64_t ThreadPool::nodes_searched() {
- lock_grab(&listener.sleepLock);
- listener.is_searching = true;
- listener.do_sleep = false;
- cond_signal(&listener.sleepCond); // Wake up listener thread
- lock_release(&listener.sleepLock);
+ int64_t nodes = 0;
+ for (Thread *th : *this)
+ nodes += th->rootPos.nodes_searched();
+ return nodes;
}
-// ThreadsManager::stop_listener() is called before to send "bestmove" to GUI to
-// return to in-sync behaviour. This is needed because while in async mode any
-// command is discarded without being processed (except for a very few ones).
+// ThreadPool::start_thinking() wakes up the main thread sleeping in
+// MainThread::idle_loop() and starts a new search, then returns immediately.
+
+void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits,
+ StateStackPtr& states) {
+ main()->join();
-void ThreadsManager::stop_listener() {
+ 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());
+ }
- Thread& listener = threads[MAX_THREADS];
+ for (const auto& m : MoveList(pos))
+ if ( limits.searchmoves.empty()
+ || std::count(limits.searchmoves.begin(), limits.searchmoves.end(), m))
+ main()->rootMoves.push_back(RootMove(m));
- lock_grab(&listener.sleepLock);
- listener.is_searching = false;
- lock_release(&listener.sleepLock);
+ main()->thinking = true;
+ main()->notify_one(); // Wake up main thread: 'thinking' must be already set
}