namespace { extern "C" {
// 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 first
- // and last thread are special. First one is the main search thread while the
- // last one mimics a timer, they run in main_loop() and timer_loop().
+ // is launched. It is a wrapper to member function pointed by start_fn.
- long start_routine(Thread* th) {
-
- if (th->threadID == 0)
- th->main_loop();
-
- else if (th->threadID == MAX_THREADS)
- th->timer_loop();
-
- else
- th->idle_loop(NULL);
-
- return 0;
- }
+ long start_routine(Thread* th) { (th->*(th->start_fn))(); return 0; }
} }
-// Thread c'tor creates and launches the OS thread, that will go immediately to
-// sleep.
+// Thread c'tor starts a newly-created thread of execution that will call
+// the idle loop function pointed by start_fn going immediately to sleep.
-Thread::Thread(int id) {
+Thread::Thread(Fn fn) {
is_searching = do_exit = false;
maxPly = splitPointsCnt = 0;
curSplitPoint = NULL;
- threadID = id;
- do_sleep = (id != 0); // Avoid a race with start_thinking()
+ start_fn = fn;
+ idx = Threads.size();
+
+ do_sleep = (fn != &Thread::main_loop); // Avoid a race with start_searching()
lock_init(sleepLock);
cond_init(sleepCond);
if (!thread_create(handle, start_routine, this))
{
- std::cerr << "Failed to create thread number " << id << std::endl;
+ std::cerr << "Failed to create thread number " << idx << std::endl;
::exit(EXIT_FAILURE);
}
}
-// Thread d'tor will wait for thread termination before to return.
+// Thread d'tor waits for thread termination before to return.
Thread::~Thread() {
// Thread::timer_loop() is where the timer thread waits maxPly milliseconds and
-// then calls do_timer_event(). If maxPly is 0 thread sleeps until is woken up.
+// then calls check_time(). If maxPly is 0 thread sleeps until is woken up.
extern void check_time();
void Thread::timer_loop() {
// Thread::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.
+// or, if "sleeping threads" is used at split time.
void Thread::wake_up() {
Signals.stopOnPonderhit = true;
lock_grab(sleepLock);
-
- while (!Signals.stop)
- cond_wait(sleepCond, sleepLock);
-
+ while (!Signals.stop) cond_wait(sleepCond, sleepLock);
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.
+// Thread::cutoff_occurred() checks whether a beta cutoff has occurred in the
+// current active split point, or in some ancestor of the split point.
bool Thread::cutoff_occurred() const {
}
-// 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
+// Thread::is_available_to() checks whether the thread is available to help the
+// thread 'master' at a split point. An obvious requirement is that thread must
+// be idle. With more than two threads, this is not sufficient: If the thread is
+// the master of some active split point, it is only available as a slave to the
+// slaves which are busy searching the split point at the top of slaves split
// point stack (the "helpful master concept" in YBWC terminology).
-bool Thread::is_available_to(int master) const {
+bool Thread::is_available_to(Thread* master) const {
if (is_searching)
return false;
// 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.
- return !spCnt || (splitPoints[spCnt - 1].slavesMask & (1ULL << master));
+ return !spCnt || (splitPoints[spCnt - 1].slavesMask & (1ULL << master->idx));
+}
+
+
+// init() is called at startup. Initializes lock and condition variable and
+// launches requested threads sending them immediately to sleep. We cannot use
+// a c'tor becuase Threads is a static object and we need a fully initialized
+// engine at this point due to allocation of endgames in Thread c'tor.
+
+void ThreadsManager::init() {
+
+ cond_init(sleepCond);
+ lock_init(splitLock);
+ timer = new Thread(&Thread::timer_loop);
+ threads.push_back(new Thread(&Thread::main_loop));
+ read_uci_options();
+}
+
+
+// d'tor cleanly terminates the threads when the program exits.
+
+ThreadsManager::~ThreadsManager() {
+
+ for (int i = 0; i < size(); i++)
+ delete threads[i];
+
+ delete timer;
+ lock_destroy(splitLock);
+ cond_destroy(sleepCond);
}
useSleepingThreads = Options["Use Sleeping Threads"];
int requested = Options["Threads"];
+ assert(requested > 0);
+
while (size() < requested)
- threads.push_back(new Thread(size()));
+ threads.push_back(new Thread(&Thread::idle_loop));
while (size() > requested)
{
// wake_up() is called before a new search to start the threads that are waiting
-// on the sleep condition. If useSleepingThreads is set threads will be woken up
-// at split time.
+// on the sleep condition and to reset maxPly. When useSleepingThreads is set
+// threads will be woken up at split time.
-void ThreadsManager::wake_up() {
+void ThreadsManager::wake_up() const {
for (int i = 0; i < size(); i++)
{
+ threads[i]->maxPly = 0;
threads[i]->do_sleep = false;
if (!useSleepingThreads)
}
-// sleep() is called after the search to ask threads to wait on sleep condition
-
-void ThreadsManager::sleep() {
-
- for (int i = 0; i < size(); i++)
- threads[i]->do_sleep = true;
-}
-
-
-// init() is called during startup. Initializes locks and condition variables
-// and launches all threads sending them immediately to sleep.
+// sleep() is called after the search finishes to ask all the threads but the
+// main one to go waiting on a sleep condition.
-void ThreadsManager::init() {
+void ThreadsManager::sleep() const {
- cond_init(sleepCond);
- lock_init(splitLock);
- timer = new Thread(MAX_THREADS);
- read_uci_options(); // Creates at least the main thread
-}
-
-
-// exit() is called to cleanly terminate the threads before the program finishes
-
-void ThreadsManager::exit() {
-
- for (int i = 0; i < size(); i++)
- delete threads[i];
-
- delete timer;
- lock_destroy(splitLock);
- cond_destroy(sleepCond);
+ for (int i = 1; i < size(); i++) // Main thread will go to sleep by itself
+ threads[i]->do_sleep = true; // to avoid a race with start_searching()
}
// 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 {
+// a slave for the thread 'master'.
- assert(master >= 0 && master < size());
+bool ThreadsManager::available_slave_exists(Thread* master) const {
for (int i = 0; i < size(); i++)
if (threads[i]->is_available_to(master))
assert(beta <= VALUE_INFINITE);
assert(depth > DEPTH_ZERO);
- int master = pos.thread();
- Thread& masterThread = *threads[master];
+ Thread* master = pos.this_thread();
- if (masterThread.splitPointsCnt >= MAX_SPLITPOINTS_PER_THREAD)
+ if (master->splitPointsCnt >= MAX_SPLITPOINTS_PER_THREAD)
return bestValue;
// Pick the next available split point from the split point stack
- SplitPoint* sp = &masterThread.splitPoints[masterThread.splitPointsCnt++];
+ SplitPoint* sp = &master->splitPoints[master->splitPointsCnt++];
- sp->parent = masterThread.curSplitPoint;
+ sp->parent = master->curSplitPoint;
sp->master = master;
sp->cutoff = false;
- sp->slavesMask = 1ULL << master;
+ sp->slavesMask = 1ULL << master->idx;
sp->depth = depth;
sp->bestMove = *bestMove;
sp->threatMove = threatMove;
sp->nodes = 0;
sp->ss = ss;
- assert(masterThread.is_searching);
+ assert(master->is_searching);
- masterThread.curSplitPoint = sp;
+ master->curSplitPoint = sp;
int slavesCnt = 0;
// Try to allocate available threads and ask them to start searching setting
// their work at this split point.
if (slavesCnt || Fake)
{
- masterThread.idle_loop(sp);
+ master->idle_loop(sp);
// In helpful master concept a master can help only a sub-tree of its split
// point, and because here is all finished is not possible master is booked.
- assert(!masterThread.is_searching);
+ assert(!master->is_searching);
}
// We have returned from the idle loop, which means that all threads are
lock_grab(sp->lock); // To protect sp->nodes
lock_grab(splitLock);
- masterThread.is_searching = true;
- masterThread.splitPointsCnt--;
- masterThread.curSplitPoint = sp->parent;
+ master->is_searching = true;
+ master->splitPointsCnt--;
+ master->curSplitPoint = sp->parent;
pos.set_nodes_searched(pos.nodes_searched() + sp->nodes);
*bestMove = sp->bestMove;
}
-// ThreadsManager::start_thinking() is used by UI thread to wake up the main
-// thread parked in main_loop() and starting a new search. If asyncMode is true
-// then function returns immediately, otherwise caller is blocked waiting for
-// the search to finish.
+// ThreadsManager::wait_for_search_finished() waits for main thread to go to
+// sleep, this means search is finished. Then returns.
-void ThreadsManager::start_thinking(const Position& pos, const LimitsType& limits,
- const std::set<Move>& searchMoves, bool async) {
- Thread& main = *threads.front();
+void ThreadsManager::wait_for_search_finished() {
- lock_grab(main.sleepLock);
-
- // Wait main thread has finished before to launch a new search
- while (!main.do_sleep)
- cond_wait(sleepCond, main.sleepLock);
-
- // Copy input arguments to initialize the search
- RootPosition.copy(pos, 0);
- Limits = limits;
- RootMoves.clear();
-
- // Populate RootMoves with all the legal moves (default) or, if a searchMoves
- // set is given, with the subset of legal moves to search.
- for (MoveList<MV_LEGAL> ml(pos); !ml.end(); ++ml)
- if (searchMoves.empty() || searchMoves.count(ml.move()))
- RootMoves.push_back(RootMove(ml.move()));
-
- // Reset signals before to start the new search
- Signals.stopOnPonderhit = Signals.firstRootMove = false;
- Signals.stop = Signals.failedLowAtRoot = false;
-
- main.do_sleep = false;
- cond_signal(main.sleepCond); // Wake up main thread and start searching
-
- if (!async)
- while (!main.do_sleep)
- cond_wait(sleepCond, main.sleepLock);
-
- lock_release(main.sleepLock);
+ Thread* t = main_thread();
+ lock_grab(t->sleepLock);
+ cond_signal(t->sleepCond); // In case is waiting for stop or ponderhit
+ while (!t->do_sleep) cond_wait(sleepCond, t->sleepLock);
+ lock_release(t->sleepLock);
}
-// ThreadsManager::stop_thinking() is used by UI thread to raise a stop request
-// and to wait for the main thread finishing the search. Needed to wait exiting
-// and terminate the threads after a 'quit' command.
-
-void ThreadsManager::stop_thinking() {
+// ThreadsManager::start_searching() wakes up the main thread sleeping in
+// main_loop() so to start a new search, then returns immediately.
- Thread& main = *threads.front();
+void ThreadsManager::start_searching(const Position& pos, const LimitsType& limits,
+ const std::vector<Move>& searchMoves) {
+ wait_for_search_finished();
- Search::Signals.stop = true;
+ SearchTime.restart(); // As early as possible
- lock_grab(main.sleepLock);
+ Signals.stopOnPonderhit = Signals.firstRootMove = false;
+ Signals.stop = Signals.failedLowAtRoot = false;
- cond_signal(main.sleepCond); // In case is waiting for stop or ponderhit
+ RootPosition.copy(pos, main_thread());
+ Limits = limits;
+ RootMoves.clear();
- while (!main.do_sleep)
- cond_wait(sleepCond, main.sleepLock);
+ for (MoveList<MV_LEGAL> ml(pos); !ml.end(); ++ml)
+ if (searchMoves.empty() || count(searchMoves.begin(), searchMoves.end(), ml.move()))
+ RootMoves.push_back(RootMove(ml.move()));
- lock_release(main.sleepLock);
+ main_thread()->do_sleep = false;
+ main_thread()->wake_up();
}
projects / stockfish / blobdiff