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::Thread(int id) {
+// 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(Fn fn) {
- threadID = id;
- do_sleep = (id != 0); // Avoid a race with start_thinking()
is_searching = do_exit = false;
maxPly = splitPointsCnt = 0;
curSplitPoint = NULL;
+ start_fn = fn;
+ threadID = 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 " << threadID << std::endl;
::exit(EXIT_FAILURE);
}
}
+// Thread d'tor waits for thread termination before to return.
+
Thread::~Thread() {
assert(do_sleep);
// 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() {
lock_grab(sleepLock);
+ do_sleep = false;
cond_signal(sleepCond);
lock_release(sleepLock);
}
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
-// point stack (the "helpful master concept" in YBWC terminology).
+// Thread::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 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 {
}
+// 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);
+}
+
+
// read_uci_options() updates internal threads parameters from the corresponding
-// UCI options. It is called before to start a new search.
+// UCI options and creates/destroys threads to match the requested number. Thread
+// objects are dynamically allocated to avoid creating in advance all possible
+// threads, with included pawns and material tables, if only few are used.
void ThreadsManager::read_uci_options() {
maxThreadsPerSplitPoint = Options["Max Threads per Split Point"];
minimumSplitDepth = Options["Min Split Depth"] * ONE_PLY;
useSleepingThreads = Options["Use Sleeping Threads"];
- activeThreads = Options["Threads"];
-
- // Dynamically allocate Thread object according to the number of
- // active threads. This avoids preallocating memory for all possible
- // threads if only few are used.
- for (int i = 0; i < MAX_THREADS; i++)
- if (i < activeThreads && !threads[i])
- threads[i] = new Thread(i);
- else if (i >= activeThreads && threads[i])
- {
- delete threads[i];
- threads[i] = NULL;
- }
-}
+ int requested = Options["Threads"];
+ assert(requested > 0);
-void ThreadsManager::wake_up() {
+ while (size() < requested)
+ threads.push_back(new Thread(&Thread::idle_loop));
- for (int i = 0; i < activeThreads; i++)
+ while (size() > requested)
{
- threads[i]->do_sleep = false;
- threads[i]->wake_up();
+ delete threads.back();
+ threads.pop_back();
}
}
-void ThreadsManager::sleep() {
-
- for (int i = 0; i < activeThreads; i++)
- threads[i]->do_sleep = true;
-}
+// wake_up() is called before a new search to start the threads that are waiting
+// on the sleep condition and to reset maxPly. When useSleepingThreads is set
+// threads will be woken up at split time.
+void ThreadsManager::wake_up() const {
-// init() is called during startup. Initializes locks and condition variables
-// and launches all threads sending them immediately to sleep.
-
-void ThreadsManager::init() {
+ for (int i = 0; i < size(); i++)
+ {
+ threads[i]->maxPly = 0;
- cond_init(sleepCond);
- lock_init(splitLock);
- timer = new Thread(MAX_THREADS);
- read_uci_options(); // Creates at least main thread
+ if (!useSleepingThreads)
+ threads[i]->wake_up();
+ }
}
-// exit() is called to cleanly terminate the threads when the program finishes
+// 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::exit() {
+void ThreadsManager::sleep() const {
- for (int i = 0; i < MAX_THREADS; i++)
- if (threads[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()
}
bool ThreadsManager::available_slave_exists(int master) const {
- assert(master >= 0 && master < activeThreads);
+ assert(master >= 0 && master < size());
- for (int i = 0; i < activeThreads; i++)
+ for (int i = 0; i < size(); i++)
if (threads[i]->is_available_to(master))
return true;
assert(alpha < beta);
assert(beta <= VALUE_INFINITE);
assert(depth > DEPTH_ZERO);
- assert(pos.thread() >= 0 && pos.thread() < activeThreads);
- assert(activeThreads > 1);
int master = pos.thread();
Thread& masterThread = *threads[master];
lock_grab(sp->lock);
lock_grab(splitLock);
- for (int i = 0; i < activeThreads && !Fake; i++)
+ for (int i = 0; i < size() && !Fake; ++i)
if (threads[i]->is_available_to(master))
{
sp->slavesMask |= 1ULL << i;
}
-// 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
+// ThreadsManager::wait_for_search_finished() waits for main thread to go to
+// sleep, this means search is finished. Then returns.
+
+void ThreadsManager::wait_for_search_finished() {
+
+ Thread* main = threads[0];
+ lock_grab(main->sleepLock);
+ while (!main->do_sleep) cond_wait(sleepCond, main->sleepLock);
+ lock_release(main->sleepLock);
+}
+
+
+// ThreadsManager::start_searching() is used by UI thread to wake up the main
+// thread parked in main_loop() and starting a new search. If async is true
// then function returns immediately, otherwise caller is blocked waiting for
// the search to finish.
-void ThreadsManager::start_thinking(const Position& pos, const LimitsType& limits,
- const std::set<Move>& searchMoves, bool async) {
- Thread& main = *threads[0];
-
- lock_grab(main.sleepLock);
+void ThreadsManager::start_searching(const Position& pos, const LimitsType& limits,
+ const std::set<Move>& searchMoves, bool async) {
+ wait_for_search_finished();
- // Wait main thread has finished before to launch a new search
- while (!main.do_sleep)
- cond_wait(sleepCond, main.sleepLock);
+ Signals.stopOnPonderhit = Signals.firstRootMove = false;
+ Signals.stop = Signals.failedLowAtRoot = false;
- // 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
+ threads[0]->wake_up(); // Start main thread
if (!async)
- while (!main.do_sleep)
- cond_wait(sleepCond, main.sleepLock);
-
- lock_release(main.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() {
-
- Thread& main = *threads[0];
-
- Search::Signals.stop = true;
-
- lock_grab(main.sleepLock);
-
- cond_signal(main.sleepCond); // In case is waiting for stop or ponderhit
-
- while (!main.do_sleep)
- cond_wait(sleepCond, main.sleepLock);
-
- lock_release(main.sleepLock);
+ wait_for_search_finished();
}
projects / stockfish / blobdiff