bool available_thread_exists(int master) const;
bool thread_is_available(int slave, int master) const;
bool thread_should_stop(int threadID) const;
- void wake_sleeping_threads();
- void put_threads_to_sleep();
+ void wake_sleeping_thread(int threadID);
void idle_loop(int threadID, SplitPoint* sp);
template <bool Fake>
friend void poll();
int ActiveThreads;
- volatile bool AllThreadsShouldExit, AllThreadsShouldSleep;
+ volatile bool AllThreadsShouldExit;
Thread threads[MAX_THREADS];
-
- Lock MPLock, WaitLock;
-
-#if !defined(_MSC_VER)
- pthread_cond_t WaitCond;
-#else
- HANDLE SitIdleEvent[MAX_THREADS];
-#endif
-
+ Lock MPLock;
+ WaitCondition WaitCond[MAX_THREADS];
};
Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply);
template <NodeType PvNode>
- inline Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply) {
- return search<PvNode, false>(pos, ss, alpha, beta, depth, ply);
- }
+ Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply);
template <NodeType PvNode>
- Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply);
+ inline Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply) {
+
+ return depth < ONE_PLY ? qsearch<PvNode>(pos, ss, alpha, beta, DEPTH_ZERO, ply)
+ : search<PvNode, false>(pos, ss, alpha, beta, depth, ply);
+ }
template <NodeType PvNode>
Depth extension(const Position& pos, Move m, bool captureOrPromotion, bool moveIsCheck, bool singleEvasion, bool mateThreat, bool* dangerous);
init_eval(ThreadsMgr.active_threads());
}
- // Wake up sleeping threads
- ThreadsMgr.wake_sleeping_threads();
-
// Set thinking time
int myTime = time[pos.side_to_move()];
int myIncrement = increment[pos.side_to_move()];
if (UseLogFile)
LogFile.close();
- ThreadsMgr.put_threads_to_sleep();
-
return !Quit;
}
Key posKey;
Move ttMove, move, excludedMove, threatMove;
Depth ext, newDepth;
+ ValueType vt;
Value bestValue, value, oldAlpha;
Value refinedValue, nullValue, futilityBase, futilityValueScaled; // Non-PV specific
bool isCheck, singleEvasion, singularExtensionNode, moveIsCheck, captureOrPromotion, dangerous;
threatMove = sp->threatMove;
mateThreat = sp->mateThreat;
goto split_point_start;
- }
+ } else {} // Hack to fix icc's "statement is unreachable" warning
// Step 1. Initialize node and poll. Polling can abort search
ThreadsMgr.incrementNodeCounter(threadID);
}
// Step 2. Check for aborted search and immediate draw
- if (AbortSearch || ThreadsMgr.thread_should_stop(threadID))
- return VALUE_DRAW;
-
- if (pos.is_draw() || ply >= PLY_MAX - 1)
+ if ( AbortSearch || ThreadsMgr.thread_should_stop(threadID)
+ || pos.is_draw() || ply >= PLY_MAX - 1)
return VALUE_DRAW;
// Step 3. Mate distance pruning
posKey = excludedMove ? pos.get_exclusion_key() : pos.get_key();
tte = TT.retrieve(posKey);
- ttMove = (tte ? tte->move() : MOVE_NONE);
+ ttMove = tte ? tte->move() : MOVE_NONE;
// At PV nodes, we don't use the TT for pruning, but only for move ordering.
// This is to avoid problems in the following areas:
// * Fifty move rule detection
// * Searching for a mate
// * Printing of full PV line
-
if (!PvNode && tte && ok_to_use_TT(tte, depth, beta, ply))
{
- // Refresh tte entry to avoid aging
- TT.store(posKey, tte->value(), tte->type(), tte->depth(), ttMove, tte->static_value(), tte->static_value_margin());
-
+ TT.refresh(tte);
ss->bestMove = ttMove; // Can be MOVE_NONE
return value_from_tt(tte->value(), ply);
}
pos.do_null_move(st);
(ss+1)->skipNullMove = true;
-
- nullValue = depth-R*ONE_PLY < ONE_PLY ? -qsearch<NonPV>(pos, ss+1, -beta, -alpha, DEPTH_ZERO, ply+1)
- : - search<NonPV>(pos, ss+1, -beta, -alpha, depth-R*ONE_PLY, ply+1);
+ nullValue = -search<NonPV>(pos, ss+1, -beta, -alpha, depth-R*ONE_PLY, ply+1);
(ss+1)->skipNullMove = false;
pos.undo_null_move();
// Initialize a MovePicker object for the current position
// FIXME currently MovePicker() c'tor is needless called also in SplitPoint
- MovePicker mpBase = MovePicker(pos, ttMove, depth, H, ss, (PvNode ? -VALUE_INFINITE : beta));
+ MovePicker mpBase(pos, ttMove, depth, H, ss, (PvNode ? -VALUE_INFINITE : beta));
MovePicker& mp = SpNode ? *sp->mp : mpBase;
CheckInfo ci(pos);
ss->bestMove = MOVE_NONE;
&& (move = mp.get_next_move()) != MOVE_NONE
&& !ThreadsMgr.thread_should_stop(threadID))
{
+ assert(move_is_ok(move));
+
if (SpNode)
{
moveCount = ++sp->moveCount;
lock_release(&(sp->lock));
}
-
- assert(move_is_ok(move));
-
- if (move == excludedMove)
+ else if (move == excludedMove)
continue;
+ else
+ movesSearched[moveCount++] = move;
moveIsCheck = pos.move_is_check(move, ci);
captureOrPromotion = pos.move_is_capture_or_promotion(move);
}
}
- newDepth = depth - ONE_PLY + ext;
-
// Update current move (this must be done after singular extension search)
- movesSearched[moveCount++] = ss->currentMove = move;
+ ss->currentMove = move;
+ newDepth = depth - ONE_PLY + ext;
// Step 12. Futility pruning (is omitted in PV nodes)
if ( !PvNode
// Step extra. pv search (only in PV nodes)
// The first move in list is the expected PV
if (!SpNode && PvNode && moveCount == 1)
- value = newDepth < ONE_PLY ? -qsearch<PV>(pos, ss+1, -beta, -alpha, DEPTH_ZERO, ply+1)
- : - search<PV>(pos, ss+1, -beta, -alpha, newDepth, ply+1);
+ value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, ply+1);
else
{
// Step 14. Reduced depth search
{
alpha = SpNode ? sp->alpha : alpha;
Depth d = newDepth - ss->reduction;
- value = d < ONE_PLY ? -qsearch<NonPV>(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO, ply+1)
- : - search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d, ply+1);
+ value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d, ply+1);
doFullDepthSearch = (value > alpha);
}
if (doFullDepthSearch)
{
alpha = SpNode ? sp->alpha : alpha;
- value = newDepth < ONE_PLY ? -qsearch<NonPV>(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO, ply+1)
- : - search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, ply+1);
+ value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, ply+1);
// Step extra. pv search (only in PV nodes)
// Search only for possible new PV nodes, if instead value >= beta then
// parent node fails low with value <= alpha and tries another move.
if (PvNode && value > alpha && value < beta)
- value = newDepth < ONE_PLY ? -qsearch<PV>(pos, ss+1, -beta, -alpha, DEPTH_ZERO, ply+1)
- : - search<PV>(pos, ss+1, -beta, -alpha, newDepth, ply+1);
+ value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, ply+1);
}
}
if (value > bestValue && !(SpNode && ThreadsMgr.thread_should_stop(threadID)))
{
bestValue = value;
+
+ if (SpNode)
+ sp->bestValue = value;
+
if (value > alpha)
{
if (SpNode && (!PvNode || value >= beta))
sp->stopRequest = true;
if (PvNode && value < beta) // We want always alpha < beta
+ {
alpha = value;
+ if (SpNode)
+ sp->alpha = value;
+ }
if (value == value_mate_in(ply + 1))
ss->mateKiller = move;
ss->bestMove = move;
- }
- if (SpNode)
- {
- sp->bestValue = bestValue;
- sp->alpha = alpha;
- sp->parentSstack->bestMove = ss->bestMove;
+
+ if (SpNode)
+ sp->parentSstack->bestMove = move;
}
}
threatMove, mateThreat, moveCount, &mp, PvNode);
}
- if (SpNode)
- {
- /* Here we have the lock still grabbed */
- sp->slaves[threadID] = 0;
- lock_release(&(sp->lock));
- return bestValue;
- }
-
// Step 19. Check for mate and stalemate
// All legal moves have been searched and if there are
// no legal moves, it must be mate or stalemate.
// If one move was excluded return fail low score.
- if (!moveCount)
+ if (!SpNode && !moveCount)
return excludedMove ? oldAlpha : isCheck ? value_mated_in(ply) : VALUE_DRAW;
// Step 20. Update tables
// If the search is not aborted, update the transposition table,
// history counters, and killer moves.
- if (AbortSearch || ThreadsMgr.thread_should_stop(threadID))
- return bestValue;
+ if (!SpNode && !AbortSearch && !ThreadsMgr.thread_should_stop(threadID))
+ {
+ move = bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove;
+ vt = bestValue <= oldAlpha ? VALUE_TYPE_UPPER
+ : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT;
- ValueType vt = (bestValue <= oldAlpha ? VALUE_TYPE_UPPER : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT);
- move = (bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove);
- TT.store(posKey, value_to_tt(bestValue, ply), vt, depth, move, ss->eval, ss->evalMargin);
+ TT.store(posKey, value_to_tt(bestValue, ply), vt, depth, move, ss->eval, ss->evalMargin);
- // Update killers and history only for non capture moves that fails high
- if ( bestValue >= beta
- && !pos.move_is_capture_or_promotion(move))
- {
+ // Update killers and history only for non capture moves that fails high
+ if ( bestValue >= beta
+ && !pos.move_is_capture_or_promotion(move))
+ {
update_history(pos, move, depth, movesSearched, moveCount);
update_killers(move, ss);
+ }
+ }
+
+ if (SpNode)
+ {
+ // Here we have the lock still grabbed
+ sp->slaves[threadID] = 0;
+ lock_release(&(sp->lock));
}
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
// If we are not thinking, wait for a condition to be signaled
// instead of wasting CPU time polling for work.
- while (AllThreadsShouldSleep || threadID >= ActiveThreads)
+ while ( threadID >= ActiveThreads
+ || threads[threadID].state == THREAD_INITIALIZING
+ || (!sp && threads[threadID].state == THREAD_AVAILABLE))
{
assert(!sp);
assert(threadID != 0);
- threads[threadID].state = THREAD_SLEEPING;
-#if !defined(_MSC_VER)
- lock_grab(&WaitLock);
- if (AllThreadsShouldSleep || threadID >= ActiveThreads)
- pthread_cond_wait(&WaitCond, &WaitLock);
- lock_release(&WaitLock);
-#else
- WaitForSingleObject(SitIdleEvent[threadID], INFINITE);
-#endif
- }
+ if (AllThreadsShouldExit)
+ break;
+
+ lock_grab(&MPLock);
+
+ // Retest condition under lock protection
+ if (!( threadID >= ActiveThreads
+ || threads[threadID].state == THREAD_INITIALIZING
+ || (!sp && threads[threadID].state == THREAD_AVAILABLE)))
+ {
+ lock_release(&MPLock);
+ continue;
+ }
- // If thread has just woken up, mark it as available
- if (threads[threadID].state == THREAD_SLEEPING)
+ // Put thread to sleep
threads[threadID].state = THREAD_AVAILABLE;
+ cond_wait(&WaitCond[threadID], &MPLock);
+ lock_release(&MPLock);
+ }
// If this thread has been assigned work, launch a search
if (threads[threadID].state == THREAD_WORKISWAITING)
{
- assert(!AllThreadsShouldExit && !AllThreadsShouldSleep);
+ assert(!AllThreadsShouldExit);
threads[threadID].state = THREAD_SEARCHING;
if (tsp->pvNode)
search<PV, true>(pos, ss, tsp->alpha, tsp->beta, tsp->depth, tsp->ply);
- else
+ else {
search<NonPV, true>(pos, ss, tsp->alpha, tsp->beta, tsp->depth, tsp->ply);
-
+ }
assert(threads[threadID].state == THREAD_SEARCHING);
threads[threadID].state = THREAD_AVAILABLE;
volatile int i;
bool ok;
-#if !defined(_MSC_VER)
- pthread_t pthread[1];
-#endif
-
// Initialize global locks
lock_init(&MPLock);
- lock_init(&WaitLock);
-#if !defined(_MSC_VER)
- pthread_cond_init(&WaitCond, NULL);
-#else
for (i = 0; i < MAX_THREADS; i++)
- SitIdleEvent[i] = CreateEvent(0, FALSE, FALSE, 0);
-#endif
+ cond_init(&WaitCond[i]);
// Initialize splitPoints[] locks
for (i = 0; i < MAX_THREADS; i++)
// Will be set just before program exits to properly end the threads
AllThreadsShouldExit = false;
- // Threads will be put to sleep as soon as created
- AllThreadsShouldSleep = true;
-
- // All threads except the main thread should be initialized to THREAD_AVAILABLE
+ // Threads will be put all threads to sleep as soon as created
ActiveThreads = 1;
+
+ // All threads except the main thread should be initialized to THREAD_INITIALIZING
threads[0].state = THREAD_SEARCHING;
for (i = 1; i < MAX_THREADS; i++)
- threads[i].state = THREAD_AVAILABLE;
+ threads[i].state = THREAD_INITIALIZING;
// Launch the helper threads
for (i = 1; i < MAX_THREADS; i++)
{
#if !defined(_MSC_VER)
+ pthread_t pthread[1];
ok = (pthread_create(pthread, NULL, init_thread, (void*)(&i)) == 0);
+ pthread_detach(pthread[0]);
#else
ok = (CreateThread(NULL, 0, init_thread, (LPVOID)(&i), 0, NULL) != NULL);
#endif
}
// Wait until the thread has finished launching and is gone to sleep
- while (threads[i].state != THREAD_SLEEPING) {}
+ while (threads[i].state == THREAD_INITIALIZING) {}
}
}
void ThreadsManager::exit_threads() {
- ActiveThreads = MAX_THREADS; // Wake up all the threads
- AllThreadsShouldExit = true; // Let the woken up threads to exit idle_loop()
- AllThreadsShouldSleep = true; // Avoid an assert in wake_sleeping_threads()
- wake_sleeping_threads();
+ AllThreadsShouldExit = true; // Let the woken up threads to exit idle_loop()
- // Wait for thread termination
+ // Wake up all the threads and waits for termination
for (int i = 1; i < MAX_THREADS; i++)
+ {
+ wake_sleeping_thread(i);
while (threads[i].state != THREAD_TERMINATED) {}
+ }
// Now we can safely destroy the locks
for (int i = 0; i < MAX_THREADS; i++)
for (int j = 0; j < MAX_ACTIVE_SPLIT_POINTS; j++)
lock_destroy(&(threads[i].splitPoints[j].lock));
- lock_destroy(&WaitLock);
lock_destroy(&MPLock);
+
+ // Now we can safely destroy the wait conditions
+ for (int i = 0; i < MAX_THREADS; i++)
+ cond_destroy(&WaitCond[i]);
}
// 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 sp_search(). When all threads have returned from sp_search() then
- // split() returns.
+ // 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 <bool Fake>
void ThreadsManager::split(const Position& p, SearchStack* ss, int ply, Value* alpha,
assert(i == master || threads[i].state == THREAD_BOOKED);
threads[i].state = THREAD_WORKISWAITING; // This makes the slave to exit from idle_loop()
+ if (i != master)
+ wake_sleeping_thread(i);
}
// Everything is set up. The master thread enters the idle loop, from
}
- // wake_sleeping_threads() wakes up all sleeping threads when it is time
+ // wake_sleeping_thread() wakes up all sleeping threads when it is time
// to start a new search from the root.
- void ThreadsManager::wake_sleeping_threads() {
-
- assert(AllThreadsShouldSleep);
- assert(ActiveThreads > 0);
-
- AllThreadsShouldSleep = false;
-
- if (ActiveThreads == 1)
- return;
-
-#if !defined(_MSC_VER)
- pthread_mutex_lock(&WaitLock);
- pthread_cond_broadcast(&WaitCond);
- pthread_mutex_unlock(&WaitLock);
-#else
- for (int i = 1; i < MAX_THREADS; i++)
- SetEvent(SitIdleEvent[i]);
-#endif
+ void ThreadsManager::wake_sleeping_thread(int threadID) {
+ lock_grab(&MPLock);
+ cond_signal(&WaitCond[threadID]);
+ lock_release(&MPLock);
}
- // put_threads_to_sleep() makes all the threads go to sleep just before
- // to leave think(), at the end of the search. Threads should have already
- // finished the job and should be idle.
-
- void ThreadsManager::put_threads_to_sleep() {
-
- assert(!AllThreadsShouldSleep);
-
- // This makes the threads to go to sleep
- AllThreadsShouldSleep = true;
- }
-
/// The RootMoveList class
// RootMoveList c'tor