X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fthread.cpp;h=6eb00d63a649b463d6dc1edea86ee3fe51f6b72a;hp=c76b4b707e9f97dfe641670de06021b982481287;hb=56d5504f6548b69ce6faaa271a8b55f3773db70c;hpb=9c9205860c5ab0e4f3180298e3f7082be259772c

diff --git a/src/thread.cpp b/src/thread.cpp
index c76b4b70..6eb00d63 100644
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -2,6 +2,7 @@
   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) 2015-2019 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
@@ -17,218 +18,202 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#include <algorithm> // For std::count
 #include <cassert>
 
+#include <algorithm> // For std::count
 #include "movegen.h"
 #include "search.h"
 #include "thread.h"
 #include "uci.h"
-
-using namespace Search;
+#include "syzygy/tbprobe.h"
+#include "tt.h"
 
 ThreadPool Threads; // Global object
 
-namespace {
-
- // Helpers to launch a thread after creation and joining before delete. Outside the
- // Thread constructor and destructor because the object must be fully initialized
- // when start_routine (and hence virtual idle_loop) is called and when joining.
-
- template<typename T> 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) {
+/// Thread constructor launches the thread and waits until it goes to sleep
+/// in idle_loop(). Note that 'searching' and 'exit' should be already set.
 
-   th->mutex.lock();
-   th->exit = true; // Search must be already finished
-   th->mutex.unlock();
-
-   th->notify_one();
-   th->join(); // Wait for thread termination
-   delete th;
- }
+Thread::Thread(size_t n) : idx(n), stdThread(&Thread::idle_loop, this) {
 
+  wait_for_search_finished();
 }
 
 
-// ThreadBase::notify_one() wakes up the thread when there is some work to do
+/// Thread destructor wakes up the thread in idle_loop() and waits
+/// for its termination. Thread should be already waiting.
+
+Thread::~Thread() {
 
-void ThreadBase::notify_one() {
+  assert(!searching);
 
-  std::unique_lock<Mutex> lk(mutex);
-  sleepCondition.notify_one();
+  exit = true;
+  start_searching();
+  stdThread.join();
 }
 
+/// Thread::bestMoveCount(Move move) return best move counter for the given root move
 
-// ThreadBase::wait() set the thread to sleep until 'condition' turns true
+int Thread::best_move_count(Move move) {
 
-void ThreadBase::wait(std::atomic_bool& condition) {
+  auto rm = std::find(rootMoves.begin() + pvIdx,
+                      rootMoves.begin() + pvLast, move);
 
-  std::unique_lock<Mutex> lk(mutex);
-  sleepCondition.wait(lk, [&]{ return bool(condition); });
+  return rm != rootMoves.begin() + pvLast ? rm->bestMoveCount : 0;
 }
 
+/// Thread::clear() reset histories, usually before a new game
 
-// ThreadBase::wait_while() set the thread to sleep until 'condition' turns false
-void ThreadBase::wait_while(std::atomic_bool& condition) {
-
-  std::unique_lock<Mutex> lk(mutex);
-  sleepCondition.wait(lk, [&]{ return !condition; });
-}
-
+void Thread::clear() {
 
-// Thread constructor makes some init but does not launch any execution thread,
-// which will be started only when the constructor returns.
+  counterMoves.fill(MOVE_NONE);
+  mainHistory.fill(0);
+  captureHistory.fill(0);
 
-Thread::Thread() {
+  for (bool inCheck : { false, true })
+    for (StatsType c : { NoCaptures, Captures })
+      for (auto& to : continuationHistory[inCheck][c])
+        for (auto& h : to)
+          h->fill(0);
 
-  searching = resetCallsCnt = false;
-  maxPly = callsCnt = 0;
-  history.clear();
-  counterMoves.clear();
-  idx = Threads.size(); // Starts from 0
+  for (bool inCheck : { false, true })
+    for (StatsType c : { NoCaptures, Captures })
+      continuationHistory[inCheck][c][NO_PIECE][0]->fill(Search::CounterMovePruneThreshold - 1);
 }
 
+/// Thread::start_searching() wakes up the thread that will start the search
 
-// Thread::idle_loop() is where the thread is parked when it has no work to do
+void Thread::start_searching() {
 
-void Thread::idle_loop() {
+  std::lock_guard<std::mutex> lk(mutex);
+  searching = true;
+  cv.notify_one(); // Wake up the thread in idle_loop()
+}
 
-  while (!exit)
-  {
-      std::unique_lock<Mutex> lk(mutex);
 
-      while (!searching && !exit)
-          sleepCondition.wait(lk);
+/// Thread::wait_for_search_finished() blocks on the condition variable
+/// until the thread has finished searching.
 
-      lk.unlock();
+void Thread::wait_for_search_finished() {
 
-      if (!exit && searching)
-          search();
-  }
+  std::unique_lock<std::mutex> lk(mutex);
+  cv.wait(lk, [&]{ return !searching; });
 }
 
 
-// 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.
+/// Thread::idle_loop() is where the thread is parked, blocked on the
+/// condition variable, when it has no work to do.
 
-void MainThread::idle_loop() {
+void Thread::idle_loop() {
 
-  while (!exit)
-  {
-      std::unique_lock<Mutex> lk(mutex);
+  // If OS already scheduled us on a different group than 0 then don't overwrite
+  // the choice, eventually we are one of many one-threaded processes running on
+  // some Windows NUMA hardware, for instance in fishtest. To make it simple,
+  // just check if running threads are below a threshold, in this case all this
+  // NUMA machinery is not needed.
+  if (Options["Threads"] > 8)
+      WinProcGroup::bindThisThread(idx);
 
-      thinking = false;
+  while (true)
+  {
+      std::unique_lock<std::mutex> lk(mutex);
+      searching = false;
+      cv.notify_one(); // Wake up anyone waiting for search finished
+      cv.wait(lk, [&]{ return searching; });
 
-      while (!thinking && !exit)
-      {
-          sleepCondition.notify_one(); // Wake up the UI thread if needed
-          sleepCondition.wait(lk);
-      }
+      if (exit)
+          return;
 
       lk.unlock();
 
-      if (!exit)
-          think();
+      search();
   }
 }
 
+/// ThreadPool::set() creates/destroys threads to match the requested number.
+/// Created and launched threads will immediately go to sleep in idle_loop.
+/// Upon resizing, threads are recreated to allow for binding if necessary.
 
-// MainThread::join() waits for main thread to finish thinking
+void ThreadPool::set(size_t requested) {
 
-void MainThread::join() {
+  if (size() > 0) { // destroy any existing thread(s)
+      main()->wait_for_search_finished();
 
-  std::unique_lock<Mutex> lk(mutex);
-  sleepCondition.wait(lk, [&]{ return !thinking; });
-}
+      while (size() > 0)
+          delete back(), pop_back();
+  }
 
+  if (requested > 0) { // create new thread(s)
+      push_back(new MainThread(0));
 
-// 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.
+      while (size() < requested)
+          push_back(new Thread(size()));
+      clear();
 
-void ThreadPool::init() {
+      // Reallocate the hash with the new threadpool size
+      TT.resize(Options["Hash"]);
 
-  push_back(new_thread<MainThread>());
-  read_uci_options();
+      // Init thread number dependent search params.
+      Search::init();
+  }
 }
 
+/// ThreadPool::clear() sets threadPool data to initial values.
 
-// ThreadPool::exit() terminates the threads before the program exits. Cannot be
-// done in destructor because threads must be terminated before freeing us.
-
-void ThreadPool::exit() {
+void ThreadPool::clear() {
 
   for (Thread* th : *this)
-      delete_thread(th);
+      th->clear();
 
-  clear(); // Get rid of stale pointers
+  main()->callsCnt = 0;
+  main()->previousScore = VALUE_INFINITE;
+  main()->previousTimeReduction = 1.0;
 }
 
+/// ThreadPool::start_thinking() wakes up main thread waiting in idle_loop() and
+/// returns immediately. Main thread will wake up other threads and start the search.
 
-// 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 ThreadPool::read_uci_options() {
-
-  size_t requested  = Options["Threads"];
-
-  assert(requested > 0);
-
-  while (size() < requested)
-      push_back(new_thread<Thread>());
-
-  while (size() > requested)
-  {
-      delete_thread(back());
-      pop_back();
-  }
-}
+void ThreadPool::start_thinking(Position& pos, StateListPtr& states,
+                                const Search::LimitsType& limits, bool ponderMode) {
 
+  main()->wait_for_search_finished();
 
-// ThreadPool::nodes_searched() returns the number of nodes searched
+  main()->stopOnPonderhit = stop = false;
+  main()->ponder = ponderMode;
+  Search::Limits = limits;
+  Search::RootMoves rootMoves;
 
-int64_t ThreadPool::nodes_searched() {
-
-  int64_t nodes = 0;
-  for (Thread *th : *this)
-      nodes += th->rootPos.nodes_searched();
-  return nodes;
-}
+  for (const auto& m : MoveList<LEGAL>(pos))
+      if (   limits.searchmoves.empty()
+          || std::count(limits.searchmoves.begin(), limits.searchmoves.end(), m))
+          rootMoves.emplace_back(m);
 
+  if (!rootMoves.empty())
+      Tablebases::rank_root_moves(pos, rootMoves);
 
-// ThreadPool::start_thinking() wakes up the main thread sleeping in
-// MainThread::idle_loop() and starts a new search, then returns immediately.
+  // 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());
 
-void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits,
-                                StateStackPtr& states) {
-  main()->join();
+  if (states.get())
+      setupStates = std::move(states); // Ownership transfer, states is now empty
 
-  Signals.stopOnPonderhit = Signals.firstRootMove = false;
-  Signals.stop = Signals.failedLowAtRoot = false;
+  // We use Position::set() to set root position across threads. But there are
+  // some StateInfo fields (previous, pliesFromNull, capturedPiece) that cannot
+  // be deduced from a fen string, so set() clears them and to not lose the info
+  // we need to backup and later restore setupStates->back(). Note that setupStates
+  // is shared by threads but is accessed in read-only mode.
+  StateInfo tmp = setupStates->back();
 
-  main()->rootMoves.clear();
-  main()->rootPos = pos;
-  Limits = limits;
-  if (states.get()) // If we don't set a new position, preserve current state
+  for (Thread* th : *this)
   {
-      SetupStates = std::move(states); // Ownership transfer here
-      assert(!states.get());
+      th->nodes = th->tbHits = th->nmpMinPly = 0;
+      th->rootDepth = th->completedDepth = 0;
+      th->rootMoves = rootMoves;
+      th->rootPos.set(pos.fen(), pos.is_chess960(), &setupStates->back(), th);
   }
 
-  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));
+  setupStates->back() = tmp;
 
-  main()->thinking = true;
-  main()->notify_one(); // Wake up main thread: 'thinking' must be already set
+  main()->start_searching();
 }