X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fthread.cpp;h=d056d2a9fd5883aa3d021a2a667bc99b6dc45789;hp=ca9fe14d8fa48dfee160df9e454fbfadb2013f53;hb=dcd8ce70941e9b8d5180eb43865bb9819e424c19;hpb=43204d9ac210a3a68b7b9785f3089d38412c1375
diff --git a/src/thread.cpp b/src/thread.cpp
index ca9fe14d..d056d2a9 100644
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -1,7 +1,8 @@
/*
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
+ 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
@@ -17,490 +18,178 @@
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 two threads are dedicated to read input from GUI and to mimic a
- // timer, so they run in listener_loop() and timer_loop() respectively.
+/// Thread constructor launch the thread and then wait until it goes to sleep
+/// in idle_loop().
-#if defined(_MSC_VER)
- DWORD WINAPI start_routine(LPVOID thread) {
-#else
- void* start_routine(void* thread) {
-#endif
+Thread::Thread() {
- if (((Thread*)thread)->threadID == MAX_THREADS)
- ((Thread*)thread)->listener_loop();
+ resetCalls = exit = false;
+ maxPly = callsCnt = 0;
+ history.clear();
+ counterMoves.clear();
+ idx = Threads.size(); // Start from 0
- else if (((Thread*)thread)->threadID == MAX_THREADS + 1)
- ((Thread*)thread)->timer_loop();
- else
- ((Thread*)thread)->idle_loop(NULL);
-
- return 0;
- }
-
-} }
-
-
-// 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.
-
-void Thread::wake_up() {
-
- lock_grab(&sleepLock);
- cond_signal(&sleepCond);
- lock_release(&sleepLock);
+ std::unique_lock lk(mutex);
+ searching = true;
+ nativeThread = std::thread(&Thread::idle_loop, this);
+ sleepCondition.wait(lk, [&]{ return !searching; });
}
-// cutoff_occurred() checks whether a beta cutoff has occurred in the current
-// active split point, or in some ancestor of the split point.
+/// Thread destructor wait for thread termination before returning
-bool Thread::cutoff_occurred() const {
+Thread::~Thread() {
- for (SplitPoint* sp = splitPoint; sp; sp = sp->parent)
- if (sp->is_betaCutoff)
- return true;
- return false;
+ mutex.lock();
+ exit = true;
+ sleepCondition.notify_one();
+ mutex.unlock();
+ nativeThread.join();
}
-// 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;
+/// Thread::wait_for_search_finished() wait on sleep condition until not searching
- // 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 Thread::wait_for_search_finished() {
- // 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 !searching; });
}
-// 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() {
+/// Thread::wait() wait on sleep condition until condition is true
- maxThreadsPerSplitPoint = Options["Maximum Number of Threads per Split Point"].value();
- minimumSplitDepth = Options["Minimum Split Depth"].value() * ONE_PLY;
- useSleepingThreads = Options["Use Sleeping Threads"].value();
+void Thread::wait(std::atomic_bool& condition) {
- set_size(Options["Threads"].value());
+ std::unique_lock lk(mutex);
+ sleepCondition.wait(lk, [&]{ return bool(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::start_searching() wake up the thread that will start the search
-void ThreadsManager::set_size(int cnt) {
+void Thread::start_searching(bool resume) {
- assert(cnt > 0 && cnt <= MAX_THREADS);
+ std::unique_lock lk(mutex);
- activeThreads = cnt;
+ if (!resume)
+ searching = true;
- 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;
+ sleepCondition.notify_one();
}
-// init() is called during startup. Initializes locks and condition variables
-// and launches all threads sending them immediately to sleep.
-
-void ThreadsManager::init() {
+/// Thread::idle_loop() is where the thread is parked when it has no work to do
- // Initialize sleep condition used to block waiting for GUI input
- cond_init(&sleepCond);
+void Thread::idle_loop() {
- // 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 + 2; 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));
- }
+ std::unique_lock lk(mutex);
- // 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
+ searching = false;
- // 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 + 2; i++)
- {
- threads[i].is_searching = false;
- threads[i].threadID = i;
-
-#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
-
- if (!ok)
+ while (!searching && !exit)
{
- std::cerr << "Failed to create thread number " << i << std::endl;
- ::exit(EXIT_FAILURE);
+ sleepCondition.notify_one(); // Wake up any waiting thread
+ sleepCondition.wait(lk);
}
- }
-}
+ lk.unlock();
-// exit() is called to cleanly terminate the threads when the program finishes
-
-void ThreadsManager::exit() {
-
- for (int i = 0; i < MAX_THREADS + 2; i++)
- {
- 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
- }
-
- // Now we can safely destroy locks and wait conditions
- lock_destroy(&threads[i].sleepLock);
- cond_destroy(&threads[i].sleepCond);
-
- for (int j = 0; j < MAX_ACTIVE_SPLIT_POINTS; j++)
- lock_destroy(&(threads[i].splitPoints[j].lock));
+ if (!exit)
+ search();
}
-
- lock_destroy(&threadsLock);
- cond_destroy(&sleepCond);
}
-// 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 {
+/// ThreadPool::init() 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.
- assert(master >= 0 && master < activeThreads);
+void ThreadPool::init() {
- for (int i = 0; i < activeThreads; i++)
- if (i != master && threads[i].is_available_to(master))
- return true;
-
- return false;
+ push_back(new MainThread);
+ read_uci_options();
}
-// split_point_finished() checks if all the slave threads of a given split
-// point have finished searching.
-
-bool ThreadsManager::split_point_finished(SplitPoint* sp) const {
-
- for (int i = 0; i < activeThreads; i++)
- if (sp->is_slave[i])
- return false;
-
- return true;
-}
-
-
-// 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))
- {
- 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();
- }
-
- 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--;
+/// ThreadPool::exit() terminate threads before the program exits. Cannot be
+/// done in destructor because threads must be terminated before deleting any
+/// static objects, so while still in main().
- lock_release(&threadsLock);
+void ThreadPool::exit() {
- masterThread.splitPoint = sp->parent;
- pos.set_nodes_searched(pos.nodes_searched() + sp->nodes);
-
- return sp->bestValue;
+ while (size())
+ delete back(), pop_back();
}
-// 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);
-
-
-// Thread::timer_loop() is where the timer thread waits maxPly milliseconds
-// and then calls do_timer_event().
-void Thread::timer_loop() {
-
- while (!do_terminate)
- {
- lock_grab(&sleepLock);
- timed_wait(&sleepCond, &sleepLock, maxPly ? maxPly : INT_MAX);
- lock_release(&sleepLock);
- do_timer_event();
- }
-}
+/// 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() {
-// ThreadsManager::set_timer() is used to set the timer to trigger after msec
-// milliseconds. If msec is 0 then timer is stopped.
+ size_t requested = Options["Threads"];
-void ThreadsManager::set_timer(int msec) {
+ assert(requested > 0);
- Thread& timer = threads[MAX_THREADS + 1];
+ while (size() < requested)
+ push_back(new Thread);
- lock_grab(&timer.sleepLock);
- timer.maxPly = msec;
- cond_signal(&timer.sleepCond); // Wake up and restart the timer
- lock_release(&timer.sleepLock);
+ while (size() > requested)
+ delete back(), pop_back();
}
-// Thread::listener_loop() is where the listener thread, used for I/O, waits for
-// input. When is_searching is false then input is read in sync with main thread
-// (that blocks), otherwise the listener thread reads any input asynchronously
-// and processes the input line calling do_uci_async_cmd().
-
-void Thread::listener_loop() {
-
- std::string cmd;
-
- while (true)
- {
- lock_grab(&sleepLock);
-
- Threads.inputLine = cmd;
- do_sleep = !is_searching;
-
- // 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);
+/// ThreadPool::nodes_searched() return the number of nodes searched
- if (do_terminate)
- return;
+int64_t ThreadPool::nodes_searched() {
- if (!std::getline(std::cin, cmd)) // Block waiting for input
- cmd = "quit";
-
- lock_grab(&sleepLock);
-
- // 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;
-
- do_uci_async_cmd(cmd);
- cmd = ""; // Input has been consumed
- }
-
- lock_release(&sleepLock);
- }
+ int64_t nodes = 0;
+ for (Thread* th : *this)
+ nodes += th->rootPos.nodes_searched();
+ return nodes;
}
-// ThreadsManager::getline() is used by main thread to block and wait for input,
-// the behaviour mimics std::getline().
-
-void ThreadsManager::getline(std::string& cmd) {
+/// ThreadPool::start_thinking() wake up the main thread sleeping in idle_loop()
+/// and start a new search, then return immediately.
- Thread& listener = threads[MAX_THREADS];
+void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits,
+ StateStackPtr& states) {
- lock_grab(&listener.sleepLock);
+ main()->wait_for_search_finished();
- listener.is_searching = false; // Set sync mode
+ Signals.stopOnPonderhit = Signals.stop = false;
- // 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())
+ main()->rootMoves.clear();
+ main()->rootPos = pos;
+ Limits = limits;
+ if (states.get()) // If we don't set a new position, preserve current state
{
- listener.do_sleep = false;
- cond_signal(&listener.sleepCond); // Wake up listener thread
-
- while (!listener.do_sleep)
- cond_wait(&sleepCond, &listener.sleepLock); // Wait for input
+ SetupStates = std::move(states); // Ownership transfer here
+ assert(!states.get());
}
- 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() {
-
- Thread& listener = threads[MAX_THREADS];
-
- lock_grab(&listener.sleepLock);
- listener.is_searching = true;
- listener.do_sleep = false;
- cond_signal(&listener.sleepCond); // Wake up listener thread
- lock_release(&listener.sleepLock);
-}
-
-
-// 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).
-
-void ThreadsManager::stop_listener() {
-
- 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()->start_searching();
}