diff --git a/src/benchmark.cpp b/src/benchmark.cpp index 5c4c4e36..8f3e6ae1 100644 --- a/src/benchmark.cpp +++ b/src/benchmark.cpp @@ -156,9 +156,10 @@ void benchmark(const Position& current, istream& is) { else { Search::StateStackPtr st; + limits.startTime = now(); Threads.start_thinking(pos, limits, st); Threads.main()->join(); - nodes += Search::RootPos.nodes_searched(); + nodes += Threads.nodes_searched(); } } diff --git a/src/movepick.cpp b/src/movepick.cpp index 7cf3e607..ed7c3800 100644 --- a/src/movepick.cpp +++ b/src/movepick.cpp @@ -238,8 +238,8 @@ void MovePicker::generate_next_stage() { /// a new pseudo legal move every time it is called, until there are no more moves /// left. It picks the move with the biggest value from a list of generated moves /// taking care not to return the ttMove if it has already been searched. -template<> -Move MovePicker::next_move() { + +Move MovePicker::next_move() { Move move; @@ -320,10 +320,3 @@ Move MovePicker::next_move() { } } } - - -/// Version of next_move() to use at split point nodes where the move is grabbed -/// from the split point's shared MovePicker object. This function is not thread -/// safe so must be lock protected by the caller. -template<> -Move MovePicker::next_move() { return ss->splitPoint->movePicker->next_move(); } diff --git a/src/movepick.h b/src/movepick.h index b488313a..d3bca28a 100644 --- a/src/movepick.h +++ b/src/movepick.h @@ -92,7 +92,7 @@ public: MovePicker(const Position&, Move, const HistoryStats&, const CounterMovesHistoryStats&, Value); MovePicker(const Position&, Move, Depth, const HistoryStats&, const CounterMovesHistoryStats&, Move, Search::Stack*); - template Move next_move(); + Move next_move(); private: template void score(); diff --git a/src/search.cpp b/src/search.cpp index 4988dc8e..3bcb7ef3 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -39,8 +39,6 @@ namespace Search { volatile SignalsType Signals; LimitsType Limits; - RootMoveVector RootMoves; - Position RootPos; StateStackPtr SetupStates; } @@ -128,21 +126,17 @@ namespace { Move pv[3]; }; - size_t PVIdx; EasyMoveManager EasyMove; double BestMoveChanges; Value DrawValue[COLOR_NB]; - HistoryStats History; CounterMovesHistoryStats CounterMovesHistory; - MovesStats Countermoves; - template + template Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode); template Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth); - void id_loop(Position& pos); Value value_to_tt(Value v, int ply); Value value_from_tt(Value v, int ply); void update_pv(Move* pv, Move move, Move* childPv); @@ -185,9 +179,13 @@ void Search::init() { void Search::reset () { TT.clear(); - History.clear(); CounterMovesHistory.clear(); - Countermoves.clear(); + + for (Thread* th : Threads) + { + th->History.clear(); + th->Countermoves.clear(); + } } @@ -221,14 +219,14 @@ uint64_t Search::perft(Position& pos, Depth depth) { template uint64_t Search::perft(Position& pos, Depth depth); -/// Search::think() is the external interface to Stockfish's search, and is -/// called by the main thread when the program receives the UCI 'go' command. It -/// searches from RootPos and at the end prints the "bestmove" to output. +/// MainThread::think() is called by the main thread when the program receives +/// the UCI 'go' command. It searches from root position and at the end prints +/// the "bestmove" to output. -void Search::think() { +void MainThread::think() { - Color us = RootPos.side_to_move(); - Time.init(Limits, us, RootPos.game_ply(), now()); + Color us = rootPos.side_to_move(); + Time.init(Limits, us, rootPos.game_ply()); int contempt = Options["Contempt"] * PawnValueEg / 100; // From centipawns DrawValue[ us] = VALUE_DRAW - Value(contempt); @@ -247,21 +245,21 @@ void Search::think() { TB::ProbeDepth = DEPTH_ZERO; } - if (RootMoves.empty()) + if (rootMoves.empty()) { - RootMoves.push_back(RootMove(MOVE_NONE)); + rootMoves.push_back(RootMove(MOVE_NONE)); sync_cout << "info depth 0 score " - << UCI::value(RootPos.checkers() ? -VALUE_MATE : VALUE_DRAW) + << UCI::value(rootPos.checkers() ? -VALUE_MATE : VALUE_DRAW) << sync_endl; } else { - if (TB::Cardinality >= RootPos.count(WHITE) - + RootPos.count(BLACK)) + if (TB::Cardinality >= rootPos.count(WHITE) + + rootPos.count(BLACK)) { // If the current root position is in the tablebases then RootMoves // contains only moves that preserve the draw or win. - TB::RootInTB = Tablebases::root_probe(RootPos, RootMoves, TB::Score); + TB::RootInTB = Tablebases::root_probe(rootPos, rootMoves, TB::Score); if (TB::RootInTB) TB::Cardinality = 0; // Do not probe tablebases during the search @@ -269,7 +267,7 @@ void Search::think() { else // If DTZ tables are missing, use WDL tables as a fallback { // Filter out moves that do not preserve a draw or win - TB::RootInTB = Tablebases::root_probe_wdl(RootPos, RootMoves, TB::Score); + TB::RootInTB = Tablebases::root_probe_wdl(rootPos, rootMoves, TB::Score); // Only probe during search if winning if (TB::Score <= VALUE_DRAW) @@ -278,7 +276,7 @@ void Search::think() { if (TB::RootInTB) { - TB::Hits = RootMoves.size(); + TB::Hits = rootMoves.size(); if (!TB::UseRule50) TB::Score = TB::Score > VALUE_DRAW ? VALUE_MATE - MAX_PLY - 1 @@ -290,21 +288,35 @@ void Search::think() { for (Thread* th : Threads) { th->maxPly = 0; - th->notify_one(); // Wake up all the threads + th->depth = DEPTH_ZERO; + th->searching = true; + if (th != this) + { + th->rootPos = Position(rootPos, th); + th->rootMoves = rootMoves; + th->notify_one(); // Wake up the thread and start searching + } } Threads.timer->run = true; Threads.timer->notify_one(); // Start the recurring timer - id_loop(RootPos); // Let's start searching ! + search(true); // Let's start searching! + // Stop the threads and the timer + Signals.stop = true; Threads.timer->run = false; + + // Wait until all threads have finished + for (Thread* th : Threads) + if (th != this) + th->wait_while(th->searching); } // When playing in 'nodes as time' mode, subtract the searched nodes from // the available ones before to exit. if (Limits.npmsec) - Time.availableNodes += Limits.inc[us] - RootPos.nodes_searched(); + Time.availableNodes += Limits.inc[us] - Threads.nodes_searched(); // When we reach the maximum depth, we can arrive here without a raise of // Signals.stop. However, if we are pondering or in an infinite search, @@ -314,196 +326,218 @@ void Search::think() { if (!Signals.stop && (Limits.ponder || Limits.infinite)) { Signals.stopOnPonderhit = true; - RootPos.this_thread()->wait_for(Signals.stop); + wait(Signals.stop); } - sync_cout << "bestmove " << UCI::move(RootMoves[0].pv[0], RootPos.is_chess960()); + sync_cout << "bestmove " << UCI::move(rootMoves[0].pv[0], rootPos.is_chess960()); - if (RootMoves[0].pv.size() > 1 || RootMoves[0].extract_ponder_from_tt(RootPos)) - std::cout << " ponder " << UCI::move(RootMoves[0].pv[1], RootPos.is_chess960()); + if (rootMoves[0].pv.size() > 1 || rootMoves[0].extract_ponder_from_tt(rootPos)) + std::cout << " ponder " << UCI::move(rootMoves[0].pv[1], rootPos.is_chess960()); std::cout << sync_endl; } -namespace { +// Thread::search() is the main iterative deepening loop. It calls search() +// repeatedly with increasing depth until the allocated thinking time has been +// consumed, user stops the search, or the maximum search depth is reached. - // id_loop() is the main iterative deepening loop. It calls search() repeatedly - // with increasing depth until the allocated thinking time has been consumed, - // user stops the search, or the maximum search depth is reached. +void Thread::search(bool isMainThread) { - void id_loop(Position& pos) { + Stack* ss = stack + 2; // To allow referencing (ss-2) and (ss+2) + Value bestValue, alpha, beta, delta; + Move easyMove = MOVE_NONE; - Stack stack[MAX_PLY+4], *ss = stack+2; // To allow referencing (ss-2) and (ss+2) - Depth depth; - Value bestValue, alpha, beta, delta; + std::memset(ss-2, 0, 5 * sizeof(Stack)); - Move easyMove = EasyMove.get(pos.key()); - EasyMove.clear(); + bestValue = delta = alpha = -VALUE_INFINITE; + beta = VALUE_INFINITE; - std::memset(ss-2, 0, 5 * sizeof(Stack)); - - depth = DEPTH_ZERO; - BestMoveChanges = 0; - bestValue = delta = alpha = -VALUE_INFINITE; - beta = VALUE_INFINITE; - - TT.new_search(); - - size_t multiPV = Options["MultiPV"]; - Skill skill(Options["Skill Level"]); - - // When playing with strength handicap enable MultiPV search that we will - // use behind the scenes to retrieve a set of possible moves. - if (skill.enabled()) - multiPV = std::max(multiPV, (size_t)4); - - multiPV = std::min(multiPV, RootMoves.size()); - - // Iterative deepening loop until requested to stop or target depth reached - while (++depth < DEPTH_MAX && !Signals.stop && (!Limits.depth || depth <= Limits.depth)) - { - // Age out PV variability metric - BestMoveChanges *= 0.5; - - // Save the last iteration's scores before first PV line is searched and - // all the move scores except the (new) PV are set to -VALUE_INFINITE. - for (RootMove& rm : RootMoves) - rm.previousScore = rm.score; - - // MultiPV loop. We perform a full root search for each PV line - for (PVIdx = 0; PVIdx < multiPV && !Signals.stop; ++PVIdx) - { - // Reset aspiration window starting size - if (depth >= 5 * ONE_PLY) - { - delta = Value(16); - alpha = std::max(RootMoves[PVIdx].previousScore - delta,-VALUE_INFINITE); - beta = std::min(RootMoves[PVIdx].previousScore + delta, VALUE_INFINITE); - } - - // Start with a small aspiration window and, in the case of a fail - // high/low, re-search with a bigger window until we're not failing - // high/low anymore. - while (true) - { - bestValue = search(pos, ss, alpha, beta, depth, false); - - // Bring the best move to the front. It is critical that sorting - // is done with a stable algorithm because all the values but the - // first and eventually the new best one are set to -VALUE_INFINITE - // and we want to keep the same order for all the moves except the - // new PV that goes to the front. Note that in case of MultiPV - // search the already searched PV lines are preserved. - std::stable_sort(RootMoves.begin() + PVIdx, RootMoves.end()); - - // Write PV back to transposition table in case the relevant - // entries have been overwritten during the search. - for (size_t i = 0; i <= PVIdx; ++i) - RootMoves[i].insert_pv_in_tt(pos); - - // If search has been stopped break immediately. Sorting and - // writing PV back to TT is safe because RootMoves is still - // valid, although it refers to previous iteration. - if (Signals.stop) - break; - - // When failing high/low give some update (without cluttering - // the UI) before a re-search. - if ( multiPV == 1 - && (bestValue <= alpha || bestValue >= beta) - && Time.elapsed() > 3000) - sync_cout << UCI::pv(pos, depth, alpha, beta) << sync_endl; - - // In case of failing low/high increase aspiration window and - // re-search, otherwise exit the loop. - if (bestValue <= alpha) - { - beta = (alpha + beta) / 2; - alpha = std::max(bestValue - delta, -VALUE_INFINITE); - - Signals.failedLowAtRoot = true; - Signals.stopOnPonderhit = false; - } - else if (bestValue >= beta) - { - alpha = (alpha + beta) / 2; - beta = std::min(bestValue + delta, VALUE_INFINITE); - } - else - break; - - delta += delta / 2; - - assert(alpha >= -VALUE_INFINITE && beta <= VALUE_INFINITE); - } - - // Sort the PV lines searched so far and update the GUI - std::stable_sort(RootMoves.begin(), RootMoves.begin() + PVIdx + 1); - - if (Signals.stop) - sync_cout << "info nodes " << RootPos.nodes_searched() - << " time " << Time.elapsed() << sync_endl; - - else if (PVIdx + 1 == multiPV || Time.elapsed() > 3000) - sync_cout << UCI::pv(pos, depth, alpha, beta) << sync_endl; - } - - // If skill level is enabled and time is up, pick a sub-optimal best move - if (skill.enabled() && skill.time_to_pick(depth)) - skill.pick_best(multiPV); - - // Have we found a "mate in x"? - if ( Limits.mate - && bestValue >= VALUE_MATE_IN_MAX_PLY - && VALUE_MATE - bestValue <= 2 * Limits.mate) - Signals.stop = true; - - // Do we have time for the next iteration? Can we stop searching now? - if (Limits.use_time_management()) - { - if (!Signals.stop && !Signals.stopOnPonderhit) - { - // Take some extra time if the best move has changed - if (depth > 4 * ONE_PLY && multiPV == 1) - Time.pv_instability(BestMoveChanges); - - // Stop the search if only one legal move is available or all - // of the available time has been used or we matched an easyMove - // from the previous search and just did a fast verification. - if ( RootMoves.size() == 1 - || Time.elapsed() > Time.available() - || ( RootMoves[0].pv[0] == easyMove - && BestMoveChanges < 0.03 - && Time.elapsed() > Time.available() / 10)) - { - // If we are allowed to ponder do not stop the search now but - // keep pondering until the GUI sends "ponderhit" or "stop". - if (Limits.ponder) - Signals.stopOnPonderhit = true; - else - Signals.stop = true; - } - } - - if (RootMoves[0].pv.size() >= 3) - EasyMove.update(pos, RootMoves[0].pv); - else - EasyMove.clear(); - } - } - - // Clear any candidate easy move that wasn't stable for the last search - // iterations; the second condition prevents consecutive fast moves. - if (EasyMove.stableCnt < 6 || Time.elapsed() < Time.available()) - EasyMove.clear(); - - // If skill level is enabled, swap best PV line with the sub-optimal one - if (skill.enabled()) - std::swap(RootMoves[0], *std::find(RootMoves.begin(), - RootMoves.end(), skill.best_move(multiPV))); + if (isMainThread) + { + easyMove = EasyMove.get(rootPos.key()); + EasyMove.clear(); + BestMoveChanges = 0; + TT.new_search(); } + size_t multiPV = Options["MultiPV"]; + Skill skill(Options["Skill Level"]); + + // When playing with strength handicap enable MultiPV search that we will + // use behind the scenes to retrieve a set of possible moves. + if (skill.enabled()) + multiPV = std::max(multiPV, (size_t)4); + + multiPV = std::min(multiPV, rootMoves.size()); + + // Iterative deepening loop until requested to stop or target depth reached + while (++depth < DEPTH_MAX && !Signals.stop && (!Limits.depth || depth <= Limits.depth)) + { + // Set up the new depth for the helper threads + if (!isMainThread) + depth = Threads.main()->depth + Depth(int(3 * log(1 + this->idx))); + + // Age out PV variability metric + if (isMainThread) + BestMoveChanges *= 0.5; + + // Save the last iteration's scores before first PV line is searched and + // all the move scores except the (new) PV are set to -VALUE_INFINITE. + for (RootMove& rm : rootMoves) + rm.previousScore = rm.score; + + // MultiPV loop. We perform a full root search for each PV line + for (PVIdx = 0; PVIdx < multiPV && !Signals.stop; ++PVIdx) + { + // Reset aspiration window starting size + if (depth >= 5 * ONE_PLY) + { + delta = Value(16); + alpha = std::max(rootMoves[PVIdx].previousScore - delta,-VALUE_INFINITE); + beta = std::min(rootMoves[PVIdx].previousScore + delta, VALUE_INFINITE); + } + + // Start with a small aspiration window and, in the case of a fail + // high/low, re-search with a bigger window until we're not failing + // high/low anymore. + while (true) + { + bestValue = ::search(rootPos, ss, alpha, beta, depth, false); + + // Bring the best move to the front. It is critical that sorting + // is done with a stable algorithm because all the values but the + // first and eventually the new best one are set to -VALUE_INFINITE + // and we want to keep the same order for all the moves except the + // new PV that goes to the front. Note that in case of MultiPV + // search the already searched PV lines are preserved. + std::stable_sort(rootMoves.begin() + PVIdx, rootMoves.end()); + + // Write PV back to transposition table in case the relevant + // entries have been overwritten during the search. + for (size_t i = 0; i <= PVIdx; ++i) + rootMoves[i].insert_pv_in_tt(rootPos); + + // If search has been stopped break immediately. Sorting and + // writing PV back to TT is safe because RootMoves is still + // valid, although it refers to previous iteration. + if (Signals.stop) + break; + + // When failing high/low give some update (without cluttering + // the UI) before a re-search. + if ( isMainThread + && multiPV == 1 + && (bestValue <= alpha || bestValue >= beta) + && Time.elapsed() > 3000) + sync_cout << UCI::pv(rootPos, depth, alpha, beta) << sync_endl; + + // In case of failing low/high increase aspiration window and + // re-search, otherwise exit the loop. + if (bestValue <= alpha) + { + beta = (alpha + beta) / 2; + alpha = std::max(bestValue - delta, -VALUE_INFINITE); + + if (isMainThread) + { + Signals.failedLowAtRoot = true; + Signals.stopOnPonderhit = false; + } + } + else if (bestValue >= beta) + { + alpha = (alpha + beta) / 2; + beta = std::min(bestValue + delta, VALUE_INFINITE); + } + else + break; + + delta += delta / 2; + + assert(alpha >= -VALUE_INFINITE && beta <= VALUE_INFINITE); + } + + // Sort the PV lines searched so far and update the GUI + std::stable_sort(rootMoves.begin(), rootMoves.begin() + PVIdx + 1); + + if (!isMainThread) + break; + + if (Signals.stop) + sync_cout << "info nodes " << Threads.nodes_searched() + << " time " << Time.elapsed() << sync_endl; + + else if (PVIdx + 1 == multiPV || Time.elapsed() > 3000) + sync_cout << UCI::pv(rootPos, depth, alpha, beta) << sync_endl; + } + + if (!isMainThread) + continue; + + // If skill level is enabled and time is up, pick a sub-optimal best move + if (skill.enabled() && skill.time_to_pick(depth)) + skill.pick_best(multiPV); + + // Have we found a "mate in x"? + if ( Limits.mate + && bestValue >= VALUE_MATE_IN_MAX_PLY + && VALUE_MATE - bestValue <= 2 * Limits.mate) + Signals.stop = true; + + // Do we have time for the next iteration? Can we stop searching now? + if (Limits.use_time_management()) + { + if (!Signals.stop && !Signals.stopOnPonderhit) + { + // Take some extra time if the best move has changed + if (depth > 4 * ONE_PLY && multiPV == 1) + Time.pv_instability(BestMoveChanges); + + // Stop the search if only one legal move is available or all + // of the available time has been used or we matched an easyMove + // from the previous search and just did a fast verification. + if ( rootMoves.size() == 1 + || Time.elapsed() > Time.available() + || ( rootMoves[0].pv[0] == easyMove + && BestMoveChanges < 0.03 + && Time.elapsed() > Time.available() / 10)) + { + // If we are allowed to ponder do not stop the search now but + // keep pondering until the GUI sends "ponderhit" or "stop". + if (Limits.ponder) + Signals.stopOnPonderhit = true; + else + Signals.stop = true; + } + } + + if (rootMoves[0].pv.size() >= 3) + EasyMove.update(rootPos, rootMoves[0].pv); + else + EasyMove.clear(); + } + } + + searching = false; + notify_one(); // Wake up main thread if is sleeping waiting for us + + if (!isMainThread) + return; + + // Clear any candidate easy move that wasn't stable for the last search + // iterations; the second condition prevents consecutive fast moves. + if (EasyMove.stableCnt < 6 || Time.elapsed() < Time.available()) + EasyMove.clear(); + + // If skill level is enabled, swap best PV line with the sub-optimal one + if (skill.enabled()) + std::swap(rootMoves[0], *std::find(rootMoves.begin(), + rootMoves.end(), skill.best_move(multiPV))); +} + + +namespace { // search<>() is the main search function for both PV and non-PV nodes and for // normal and SplitPoint nodes. When called just after a split point the search @@ -512,7 +546,7 @@ namespace { // repeat all this work again. We also don't need to store anything to the hash // table here: This is taken care of after we return from the split point. - template + template Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode) { const bool RootNode = NT == Root; @@ -525,7 +559,6 @@ namespace { Move pv[MAX_PLY+1], quietsSearched[64]; StateInfo st; TTEntry* tte; - SplitPoint* splitPoint; Key posKey; Move ttMove, move, excludedMove, bestMove; Depth extension, newDepth, predictedDepth; @@ -537,22 +570,6 @@ namespace { // Step 1. Initialize node Thread* thisThread = pos.this_thread(); inCheck = pos.checkers(); - - if (SpNode) - { - splitPoint = ss->splitPoint; - bestMove = splitPoint->bestMove; - bestValue = splitPoint->bestValue; - tte = nullptr; - ttHit = false; - ttMove = excludedMove = MOVE_NONE; - ttValue = VALUE_NONE; - - assert(splitPoint->bestValue > -VALUE_INFINITE && splitPoint->moveCount > 0); - - goto moves_loop; - } - moveCount = quietCount = ss->moveCount = 0; bestValue = -VALUE_INFINITE; ss->ply = (ss-1)->ply + 1; @@ -591,7 +608,7 @@ namespace { excludedMove = ss->excludedMove; posKey = excludedMove ? pos.exclusion_key() : pos.key(); tte = TT.probe(posKey, ttHit); - ss->ttMove = ttMove = RootNode ? RootMoves[PVIdx].pv[0] : ttHit ? tte->move() : MOVE_NONE; + ss->ttMove = ttMove = RootNode ? thisThread->rootMoves[thisThread->PVIdx].pv[0] : ttHit ? tte->move() : MOVE_NONE; ttValue = ttHit ? value_from_tt(tte->value(), ss->ply) : VALUE_NONE; // At non-PV nodes we check for a fail high/low. We don't prune at PV nodes @@ -710,7 +727,7 @@ namespace { pos.do_null_move(st); (ss+1)->skipEarlyPruning = true; nullValue = depth-R < ONE_PLY ? -qsearch(pos, ss+1, -beta, -beta+1, DEPTH_ZERO) - : - search(pos, ss+1, -beta, -beta+1, depth-R, !cutNode); + : - search(pos, ss+1, -beta, -beta+1, depth-R, !cutNode); (ss+1)->skipEarlyPruning = false; pos.undo_null_move(); @@ -726,7 +743,7 @@ namespace { // Do verification search at high depths ss->skipEarlyPruning = true; Value v = depth-R < ONE_PLY ? qsearch(pos, ss, beta-1, beta, DEPTH_ZERO) - : search(pos, ss, beta-1, beta, depth-R, false); + : search(pos, ss, beta-1, beta, depth-R, false); ss->skipEarlyPruning = false; if (v >= beta) @@ -749,15 +766,15 @@ namespace { assert((ss-1)->currentMove != MOVE_NONE); assert((ss-1)->currentMove != MOVE_NULL); - MovePicker mp(pos, ttMove, History, CounterMovesHistory, PieceValue[MG][pos.captured_piece_type()]); + MovePicker mp(pos, ttMove, thisThread->History, CounterMovesHistory, PieceValue[MG][pos.captured_piece_type()]); CheckInfo ci(pos); - while ((move = mp.next_move()) != MOVE_NONE) + while ((move = mp.next_move()) != MOVE_NONE) if (pos.legal(move, ci.pinned)) { ss->currentMove = move; pos.do_move(move, st, pos.gives_check(move, ci)); - value = -search(pos, ss+1, -rbeta, -rbeta+1, rdepth, !cutNode); + value = -search(pos, ss+1, -rbeta, -rbeta+1, rdepth, !cutNode); pos.undo_move(move); if (value >= rbeta) return value; @@ -771,19 +788,19 @@ namespace { { Depth d = depth - 2 * ONE_PLY - (PvNode ? DEPTH_ZERO : depth / 4); ss->skipEarlyPruning = true; - search(pos, ss, alpha, beta, d, true); + search(pos, ss, alpha, beta, d, true); ss->skipEarlyPruning = false; tte = TT.probe(posKey, ttHit); ttMove = ttHit ? tte->move() : MOVE_NONE; } -moves_loop: // When in check and at SpNode search starts from here +moves_loop: // When in check search starts from here Square prevMoveSq = to_sq((ss-1)->currentMove); - Move countermove = Countermoves[pos.piece_on(prevMoveSq)][prevMoveSq]; + Move countermove = thisThread->Countermoves[pos.piece_on(prevMoveSq)][prevMoveSq]; - MovePicker mp(pos, ttMove, depth, History, CounterMovesHistory, countermove, ss); + MovePicker mp(pos, ttMove, depth, thisThread->History, CounterMovesHistory, countermove, ss); CheckInfo ci(pos); value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc improving = ss->staticEval >= (ss-2)->staticEval @@ -791,7 +808,6 @@ moves_loop: // When in check and at SpNode search starts from here ||(ss-2)->staticEval == VALUE_NONE; singularExtensionNode = !RootNode - && !SpNode && depth >= 8 * ONE_PLY && ttMove != MOVE_NONE /* && ttValue != VALUE_NONE Already implicit in the next condition */ @@ -802,7 +818,7 @@ moves_loop: // When in check and at SpNode search starts from here // Step 11. Loop through moves // Loop through all pseudo-legal moves until no moves remain or a beta cutoff occurs - while ((move = mp.next_move()) != MOVE_NONE) + while ((move = mp.next_move()) != MOVE_NONE) { assert(is_ok(move)); @@ -812,29 +828,19 @@ moves_loop: // When in check and at SpNode search starts from here // At root obey the "searchmoves" option and skip moves not listed in Root // Move List. As a consequence any illegal move is also skipped. In MultiPV // mode we also skip PV moves which have been already searched. - if (RootNode && !std::count(RootMoves.begin() + PVIdx, RootMoves.end(), move)) + if (RootNode && !std::count(thisThread->rootMoves.begin() + thisThread->PVIdx, thisThread->rootMoves.end(), move)) continue; - if (SpNode) - { - // Shared counter cannot be decremented later if the move turns out to be illegal - if (!pos.legal(move, ci.pinned)) - continue; + ss->moveCount = ++moveCount; - ss->moveCount = moveCount = ++splitPoint->moveCount; - splitPoint->spinlock.release(); - } - else - ss->moveCount = ++moveCount; - - if (RootNode) + if (RootNode && thisThread == Threads.main()) { Signals.firstRootMove = (moveCount == 1); - if (thisThread == Threads.main() && Time.elapsed() > 3000) + if (Time.elapsed() > 3000) sync_cout << "info depth " << depth / ONE_PLY << " currmove " << UCI::move(move, pos.is_chess960()) - << " currmovenumber " << moveCount + PVIdx << sync_endl; + << " currmovenumber " << moveCount + thisThread->PVIdx << sync_endl; } if (PvNode) @@ -864,7 +870,7 @@ moves_loop: // When in check and at SpNode search starts from here Value rBeta = ttValue - 2 * depth / ONE_PLY; ss->excludedMove = move; ss->skipEarlyPruning = true; - value = search(pos, ss, rBeta - 1, rBeta, depth / 2, cutNode); + value = search(pos, ss, rBeta - 1, rBeta, depth / 2, cutNode); ss->skipEarlyPruning = false; ss->excludedMove = MOVE_NONE; @@ -886,12 +892,7 @@ moves_loop: // When in check and at SpNode search starts from here // Move count based pruning if ( depth < 16 * ONE_PLY && moveCount >= FutilityMoveCounts[improving][depth]) - { - if (SpNode) - splitPoint->spinlock.acquire(); - continue; - } predictedDepth = newDepth - reduction(improving, depth, moveCount); @@ -903,32 +904,20 @@ moves_loop: // When in check and at SpNode search starts from here if (futilityValue <= alpha) { bestValue = std::max(bestValue, futilityValue); - - if (SpNode) - { - splitPoint->spinlock.acquire(); - if (bestValue > splitPoint->bestValue) - splitPoint->bestValue = bestValue; - } continue; } } // Prune moves with negative SEE at low depths if (predictedDepth < 4 * ONE_PLY && pos.see_sign(move) < VALUE_ZERO) - { - if (SpNode) - splitPoint->spinlock.acquire(); - continue; - } } // Speculative prefetch as early as possible prefetch(TT.first_entry(pos.key_after(move))); // Check for legality just before making the move - if (!RootNode && !SpNode && !pos.legal(move, ci.pinned)) + if (!RootNode && !pos.legal(move, ci.pinned)) { ss->moveCount = --moveCount; continue; @@ -950,12 +939,12 @@ moves_loop: // When in check and at SpNode search starts from here ss->reduction = reduction(improving, depth, moveCount); if ( (!PvNode && cutNode) - || ( History[pos.piece_on(to_sq(move))][to_sq(move)] < VALUE_ZERO + || ( thisThread->History[pos.piece_on(to_sq(move))][to_sq(move)] < VALUE_ZERO && CounterMovesHistory[pos.piece_on(prevMoveSq)][prevMoveSq] [pos.piece_on(to_sq(move))][to_sq(move)] <= VALUE_ZERO)) ss->reduction += ONE_PLY; - if ( History[pos.piece_on(to_sq(move))][to_sq(move)] > VALUE_ZERO + if ( thisThread->History[pos.piece_on(to_sq(move))][to_sq(move)] > VALUE_ZERO && CounterMovesHistory[pos.piece_on(prevMoveSq)][prevMoveSq] [pos.piece_on(to_sq(move))][to_sq(move)] > VALUE_ZERO) ss->reduction = std::max(DEPTH_ZERO, ss->reduction - ONE_PLY); @@ -968,10 +957,8 @@ moves_loop: // When in check and at SpNode search starts from here ss->reduction = std::max(DEPTH_ZERO, ss->reduction - ONE_PLY); Depth d = std::max(newDepth - ss->reduction, ONE_PLY); - if (SpNode) - alpha = splitPoint->alpha; - value = -search(pos, ss+1, -(alpha+1), -alpha, d, true); + value = -search(pos, ss+1, -(alpha+1), -alpha, d, true); doFullDepthSearch = (value > alpha && ss->reduction != DEPTH_ZERO); ss->reduction = DEPTH_ZERO; @@ -981,15 +968,10 @@ moves_loop: // When in check and at SpNode search starts from here // Step 16. Full depth search, when LMR is skipped or fails high if (doFullDepthSearch) - { - if (SpNode) - alpha = splitPoint->alpha; - value = newDepth < ONE_PLY ? givesCheck ? -qsearch(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO) : -qsearch(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO) - : - search(pos, ss+1, -(alpha+1), -alpha, newDepth, !cutNode); - } + : - search(pos, ss+1, -(alpha+1), -alpha, newDepth, !cutNode); // For PV nodes only, do a full PV search on the first move or after a fail // high (in the latter case search only if value < beta), otherwise let the @@ -1002,7 +984,7 @@ moves_loop: // When in check and at SpNode search starts from here value = newDepth < ONE_PLY ? givesCheck ? -qsearch(pos, ss+1, -beta, -alpha, DEPTH_ZERO) : -qsearch(pos, ss+1, -beta, -alpha, DEPTH_ZERO) - : - search(pos, ss+1, -beta, -alpha, newDepth, false); + : - search(pos, ss+1, -beta, -alpha, newDepth, false); } // Step 17. Undo move @@ -1011,22 +993,15 @@ moves_loop: // When in check and at SpNode search starts from here assert(value > -VALUE_INFINITE && value < VALUE_INFINITE); // Step 18. Check for new best move - if (SpNode) - { - splitPoint->spinlock.acquire(); - bestValue = splitPoint->bestValue; - alpha = splitPoint->alpha; - } - - // Finished searching the move. If a stop or a cutoff occurred, the return - // value of the search cannot be trusted, and we return immediately without + // Finished searching the move. If a stop occurred, the return value of + // the search cannot be trusted, and we return immediately without // updating best move, PV and TT. - if (Signals.stop || thisThread->cutoff_occurred()) + if (Signals.stop) return VALUE_ZERO; if (RootNode) { - RootMove& rm = *std::find(RootMoves.begin(), RootMoves.end(), move); + RootMove& rm = *std::find(thisThread->rootMoves.begin(), thisThread->rootMoves.end(), move); // PV move or new best move ? if (moveCount == 1 || value > alpha) @@ -1042,7 +1017,7 @@ moves_loop: // When in check and at SpNode search starts from here // We record how often the best move has been changed in each // iteration. This information is used for time management: When // the best move changes frequently, we allocate some more time. - if (moveCount > 1) + if (moveCount > 1 && thisThread == Threads.main()) ++BestMoveChanges; } else @@ -1054,69 +1029,41 @@ moves_loop: // When in check and at SpNode search starts from here if (value > bestValue) { - bestValue = SpNode ? splitPoint->bestValue = value : value; + bestValue = value; if (value > alpha) { // If there is an easy move for this position, clear it if unstable if ( PvNode + && thisThread == Threads.main() && EasyMove.get(pos.key()) && (move != EasyMove.get(pos.key()) || moveCount > 1)) EasyMove.clear(); - bestMove = SpNode ? splitPoint->bestMove = move : move; + bestMove = move; if (PvNode && !RootNode) // Update pv even in fail-high case - update_pv(SpNode ? splitPoint->ss->pv : ss->pv, move, (ss+1)->pv); + update_pv(ss->pv, move, (ss+1)->pv); if (PvNode && value < beta) // Update alpha! Always alpha < beta - alpha = SpNode ? splitPoint->alpha = value : value; + alpha = value; else { assert(value >= beta); // Fail high - - if (SpNode) - splitPoint->cutoff = true; - break; } } } - if (!SpNode && !captureOrPromotion && move != bestMove && quietCount < 64) + if (!captureOrPromotion && move != bestMove && quietCount < 64) quietsSearched[quietCount++] = move; - - // Step 19. Check for splitting the search - if ( !SpNode - && Threads.size() >= 2 - && depth >= Threads.minimumSplitDepth - && ( !thisThread->activeSplitPoint - || !thisThread->activeSplitPoint->allSlavesSearching - || ( Threads.size() > MAX_SLAVES_PER_SPLITPOINT - && thisThread->activeSplitPoint->slavesMask.count() == MAX_SLAVES_PER_SPLITPOINT)) - && thisThread->splitPointsSize < MAX_SPLITPOINTS_PER_THREAD) - { - assert(bestValue > -VALUE_INFINITE && bestValue < beta); - - thisThread->split(pos, ss, alpha, beta, &bestValue, &bestMove, - depth, moveCount, &mp, NT, cutNode); - - if (Signals.stop || thisThread->cutoff_occurred()) - return VALUE_ZERO; - - if (bestValue >= beta) - break; - } } - if (SpNode) - return bestValue; - - // Following condition would detect a stop or a cutoff set only after move - // loop has been completed. But in this case bestValue is valid because we - // have fully searched our subtree, and we can anyhow save the result in TT. + // Following condition would detect a stop only after move loop has been + // completed. But in this case bestValue is valid because we have fully + // searched our subtree, and we can anyhow save the result in TT. /* - if (Signals.stop || thisThread->cutoff_occurred()) + if (Signals.stop) return VALUE_DRAW; */ @@ -1262,11 +1209,11 @@ moves_loop: // When in check and at SpNode search starts from here // to search the moves. Because the depth is <= 0 here, only captures, // queen promotions and checks (only if depth >= DEPTH_QS_CHECKS) will // be generated. - MovePicker mp(pos, ttMove, depth, History, CounterMovesHistory, to_sq((ss-1)->currentMove)); + MovePicker mp(pos, ttMove, depth, pos.this_thread()->History, CounterMovesHistory, to_sq((ss-1)->currentMove)); CheckInfo ci(pos); // Loop through the moves until no moves remain or a beta cutoff occurs - while ((move = mp.next_move()) != MOVE_NONE) + while ((move = mp.next_move()) != MOVE_NONE) { assert(is_ok(move)); @@ -1417,19 +1364,20 @@ moves_loop: // When in check and at SpNode search starts from here Square prevSq = to_sq((ss-1)->currentMove); HistoryStats& cmh = CounterMovesHistory[pos.piece_on(prevSq)][prevSq]; + Thread* thisThread = pos.this_thread(); - History.updateH(pos.moved_piece(move), to_sq(move), bonus); + thisThread->History.updateH(pos.moved_piece(move), to_sq(move), bonus); if (is_ok((ss-1)->currentMove)) { - Countermoves.update(pos.piece_on(prevSq), prevSq, move); + thisThread->Countermoves.update(pos.piece_on(prevSq), prevSq, move); cmh.updateCMH(pos.moved_piece(move), to_sq(move), bonus); } // Decrease all the other played quiet moves for (int i = 0; i < quietsCnt; ++i) { - History.updateH(pos.moved_piece(quiets[i]), to_sq(quiets[i]), -bonus); + thisThread->History.updateH(pos.moved_piece(quiets[i]), to_sq(quiets[i]), -bonus); if (is_ok((ss-1)->currentMove)) cmh.updateCMH(pos.moved_piece(quiets[i]), to_sq(quiets[i]), -bonus); @@ -1451,10 +1399,11 @@ moves_loop: // When in check and at SpNode search starts from here Move Skill::pick_best(size_t multiPV) { // PRNG sequence should be non-deterministic, so we seed it with the time at init + const Search::RootMoveVector& rootMoves = Threads.main()->rootMoves; static PRNG rng(now()); // RootMoves are already sorted by score in descending order - int variance = std::min(RootMoves[0].score - RootMoves[multiPV - 1].score, PawnValueMg); + int variance = std::min(rootMoves[0].score - rootMoves[multiPV - 1].score, PawnValueMg); int weakness = 120 - 2 * level; int maxScore = -VALUE_INFINITE; @@ -1464,13 +1413,13 @@ moves_loop: // When in check and at SpNode search starts from here for (size_t i = 0; i < multiPV; ++i) { // This is our magic formula - int push = ( weakness * int(RootMoves[0].score - RootMoves[i].score) + int push = ( weakness * int(rootMoves[0].score - rootMoves[i].score) + variance * (rng.rand() % weakness)) / 128; - if (RootMoves[i].score + push > maxScore) + if (rootMoves[i].score + push > maxScore) { - maxScore = RootMoves[i].score + push; - best = RootMoves[i].pv[0]; + maxScore = rootMoves[i].score + push; + best = rootMoves[i].pv[0]; } } return best; @@ -1486,12 +1435,10 @@ string UCI::pv(const Position& pos, Depth depth, Value alpha, Value beta) { std::stringstream ss; int elapsed = Time.elapsed() + 1; - size_t multiPV = std::min((size_t)Options["MultiPV"], RootMoves.size()); - int selDepth = 0; - - for (Thread* th : Threads) - if (th->maxPly > selDepth) - selDepth = th->maxPly; + const Search::RootMoveVector& rootMoves = pos.this_thread()->rootMoves; + size_t PVIdx = pos.this_thread()->PVIdx; + size_t multiPV = std::min((size_t)Options["MultiPV"], rootMoves.size()); + uint64_t nodes_searched = Threads.nodes_searched(); for (size_t i = 0; i < multiPV; ++i) { @@ -1501,7 +1448,7 @@ string UCI::pv(const Position& pos, Depth depth, Value alpha, Value beta) { continue; Depth d = updated ? depth : depth - ONE_PLY; - Value v = updated ? RootMoves[i].score : RootMoves[i].previousScore; + Value v = updated ? rootMoves[i].score : rootMoves[i].previousScore; bool tb = TB::RootInTB && abs(v) < VALUE_MATE - MAX_PLY; v = tb ? TB::Score : v; @@ -1511,15 +1458,15 @@ string UCI::pv(const Position& pos, Depth depth, Value alpha, Value beta) { ss << "info" << " depth " << d / ONE_PLY - << " seldepth " << selDepth + << " seldepth " << pos.this_thread()->maxPly << " multipv " << i + 1 << " score " << UCI::value(v); if (!tb && i == PVIdx) ss << (v >= beta ? " lowerbound" : v <= alpha ? " upperbound" : ""); - ss << " nodes " << pos.nodes_searched() - << " nps " << pos.nodes_searched() * 1000 / elapsed; + ss << " nodes " << nodes_searched + << " nps " << nodes_searched * 1000 / elapsed; if (elapsed > 1000) // Earlier makes little sense ss << " hashfull " << TT.hashfull(); @@ -1528,7 +1475,7 @@ string UCI::pv(const Position& pos, Depth depth, Value alpha, Value beta) { << " time " << elapsed << " pv"; - for (Move m : RootMoves[i].pv) + for (Move m : rootMoves[i].pv) ss << " " << UCI::move(m, pos.is_chess960()); } @@ -1589,144 +1536,6 @@ bool RootMove::extract_ponder_from_tt(Position& pos) } -/// Thread::idle_loop() is where the thread is parked when it has no work to do - -void Thread::idle_loop() { - - // Pointer 'this_sp' is not null only if we are called from split(), and not - // at the thread creation. This means we are the split point's master. - SplitPoint* this_sp = activeSplitPoint; - - assert(!this_sp || (this_sp->master == this && searching)); - - while (!exit && !(this_sp && this_sp->slavesMask.none())) - { - // If this thread has been assigned work, launch a search - while (searching) - { - spinlock.acquire(); - - assert(activeSplitPoint); - SplitPoint* sp = activeSplitPoint; - - spinlock.release(); - - Stack stack[MAX_PLY+4], *ss = stack+2; // To allow referencing (ss-2) and (ss+2) - Position pos(*sp->pos, this); - - std::memcpy(ss-2, sp->ss-2, 5 * sizeof(Stack)); - ss->splitPoint = sp; - - sp->spinlock.acquire(); - - assert(activePosition == nullptr); - - activePosition = &pos; - - if (sp->nodeType == NonPV) - search(pos, ss, sp->alpha, sp->beta, sp->depth, sp->cutNode); - - else if (sp->nodeType == PV) - search(pos, ss, sp->alpha, sp->beta, sp->depth, sp->cutNode); - - else if (sp->nodeType == Root) - search(pos, ss, sp->alpha, sp->beta, sp->depth, sp->cutNode); - - else - assert(false); - - assert(searching); - - spinlock.acquire(); - - searching = false; - activePosition = nullptr; - - spinlock.release(); - - sp->slavesMask.reset(idx); - sp->allSlavesSearching = false; - sp->nodes += pos.nodes_searched(); - - // After releasing the lock we can't access any SplitPoint related data - // in a safe way because it could have been released under our feet by - // the sp master. - sp->spinlock.release(); - - // Try to late join to another split point if none of its slaves has - // already finished. - SplitPoint* bestSp = NULL; - int minLevel = INT_MAX; - - for (Thread* th : Threads) - { - const size_t size = th->splitPointsSize; // Local copy - sp = size ? &th->splitPoints[size - 1] : nullptr; - - if ( sp - && sp->allSlavesSearching - && sp->slavesMask.count() < MAX_SLAVES_PER_SPLITPOINT - && can_join(sp)) - { - assert(this != th); - assert(!(this_sp && this_sp->slavesMask.none())); - assert(Threads.size() > 2); - - // Prefer to join to SP with few parents to reduce the probability - // that a cut-off occurs above us, and hence we waste our work. - int level = 0; - for (SplitPoint* p = th->activeSplitPoint; p; p = p->parentSplitPoint) - level++; - - if (level < minLevel) - { - bestSp = sp; - minLevel = level; - } - } - } - - if (bestSp) - { - sp = bestSp; - - // Recheck the conditions under lock protection - sp->spinlock.acquire(); - - if ( sp->allSlavesSearching - && sp->slavesMask.count() < MAX_SLAVES_PER_SPLITPOINT) - { - spinlock.acquire(); - - if (can_join(sp)) - { - sp->slavesMask.set(idx); - activeSplitPoint = sp; - searching = true; - } - - spinlock.release(); - } - - sp->spinlock.release(); - } - } - - // If search is finished then sleep, otherwise just yield - if (!Threads.main()->thinking) - { - assert(!this_sp); - - std::unique_lock lk(mutex); - while (!exit && !Threads.main()->thinking) - sleepCondition.wait(lk); - } - else - std::this_thread::yield(); // Wait for a new job or for our slaves to finish - } -} - - /// check_time() is called by the timer thread when the timer triggers. It is /// used to print debug info and, more importantly, to detect when we are out of /// available time and thus stop the search. @@ -1759,30 +1568,6 @@ void check_time() { else if (Limits.movetime && elapsed >= Limits.movetime) Signals.stop = true; - else if (Limits.nodes) - { - int64_t nodes = RootPos.nodes_searched(); - - // Loop across all split points and sum accumulated SplitPoint nodes plus - // all the currently active positions nodes. - // FIXME: Racy... - for (Thread* th : Threads) - for (size_t i = 0; i < th->splitPointsSize; ++i) - { - SplitPoint& sp = th->splitPoints[i]; - - sp.spinlock.acquire(); - - nodes += sp.nodes; - - for (size_t idx = 0; idx < Threads.size(); ++idx) - if (sp.slavesMask.test(idx) && Threads[idx]->activePosition) - nodes += Threads[idx]->activePosition->nodes_searched(); - - sp.spinlock.release(); - } - - if (nodes >= Limits.nodes) + else if (Limits.nodes && Threads.nodes_searched() >= Limits.nodes) Signals.stop = true; - } } diff --git a/src/search.h b/src/search.h index 5ba95fe0..c7abb9dc 100644 --- a/src/search.h +++ b/src/search.h @@ -88,6 +88,7 @@ struct LimitsType { std::vector searchmoves; int time[COLOR_NB], inc[COLOR_NB], npmsec, movestogo, depth, movetime, mate, infinite, ponder; int64_t nodes; + TimePoint startTime; }; /// The SignalsType struct stores volatile flags updated during the search @@ -101,12 +102,9 @@ typedef std::unique_ptr> StateStackPtr; extern volatile SignalsType Signals; extern LimitsType Limits; -extern RootMoveVector RootMoves; -extern Position RootPos; extern StateStackPtr SetupStates; void init(); -void think(); void reset(); template uint64_t perft(Position& pos, Depth depth); diff --git a/src/thread.cpp b/src/thread.cpp index cdb0d541..88b45921 100644 --- a/src/thread.cpp +++ b/src/thread.cpp @@ -66,15 +66,24 @@ void ThreadBase::notify_one() { } -// ThreadBase::wait_for() set the thread to sleep until 'condition' turns true +// ThreadBase::wait() set the thread to sleep until 'condition' turns true -void ThreadBase::wait_for(volatile const bool& condition) { +void ThreadBase::wait(volatile const bool& condition) { std::unique_lock lk(mutex); sleepCondition.wait(lk, [&]{ return condition; }); } +// ThreadBase::wait_while() set the thread to sleep until 'condition' turns false + +void ThreadBase::wait_while(volatile const bool& condition) { + + std::unique_lock lk(mutex); + sleepCondition.wait(lk, [&]{ return !condition; }); +} + + // Thread c'tor makes some init but does not launch any execution thread that // will be started only when c'tor returns. @@ -82,143 +91,10 @@ Thread::Thread() /* : splitPoints() */ { // Initialization of non POD broken in searching = false; maxPly = 0; - splitPointsSize = 0; - activeSplitPoint = nullptr; - activePosition = nullptr; idx = Threads.size(); // Starts from 0 } -// 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 { - - for (SplitPoint* sp = activeSplitPoint; sp; sp = sp->parentSplitPoint) - if (sp->cutoff) - return true; - - return false; -} - - -// Thread::can_join() checks whether the thread is available to join the split -// point 'sp'. 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 split -// point, it is only available as a slave for the split points below his active -// one (the "helpful master" concept in YBWC terminology). - -bool Thread::can_join(const SplitPoint* sp) const { - - if (searching) - return false; - - // Make a local copy to be sure it doesn't become zero under our feet while - // testing next condition and so leading to an out of bounds access. - const size_t size = splitPointsSize; - - // No split points means that the thread is available as a slave for any - // other thread otherwise apply the "helpful master" concept if possible. - return !size || splitPoints[size - 1].slavesMask.test(sp->master->idx); -} - - -// Thread::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), 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 then helper threads are -// informed 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. - -void Thread::split(Position& pos, Stack* ss, Value alpha, Value beta, Value* bestValue, - Move* bestMove, Depth depth, int moveCount, - MovePicker* movePicker, int nodeType, bool cutNode) { - - assert(searching); - assert(-VALUE_INFINITE < *bestValue && *bestValue <= alpha && alpha < beta && beta <= VALUE_INFINITE); - assert(depth >= Threads.minimumSplitDepth); - assert(splitPointsSize < MAX_SPLITPOINTS_PER_THREAD); - - // Pick and init the next available split point - SplitPoint& sp = splitPoints[splitPointsSize]; - - sp.spinlock.acquire(); // No contention here until we don't increment splitPointsSize - - sp.master = this; - sp.parentSplitPoint = activeSplitPoint; - sp.slavesMask = 0, sp.slavesMask.set(idx); - sp.depth = depth; - sp.bestValue = *bestValue; - sp.bestMove = *bestMove; - sp.alpha = alpha; - sp.beta = beta; - sp.nodeType = nodeType; - sp.cutNode = cutNode; - sp.movePicker = movePicker; - sp.moveCount = moveCount; - sp.pos = &pos; - sp.nodes = 0; - sp.cutoff = false; - sp.ss = ss; - sp.allSlavesSearching = true; // Must be set under lock protection - - ++splitPointsSize; - activeSplitPoint = &sp; - activePosition = nullptr; - - // Try to allocate available threads - Thread* slave; - - while ( sp.slavesMask.count() < MAX_SLAVES_PER_SPLITPOINT - && (slave = Threads.available_slave(&sp)) != nullptr) - { - slave->spinlock.acquire(); - - if (slave->can_join(activeSplitPoint)) - { - activeSplitPoint->slavesMask.set(slave->idx); - slave->activeSplitPoint = activeSplitPoint; - slave->searching = true; - } - - slave->spinlock.release(); - } - - // Everything is set up. The master thread enters the idle loop, from which - // it will instantly launch a search, because its 'searching' flag is set. - // The thread will return from the idle loop when all slaves have finished - // their work at this split point. - sp.spinlock.release(); - - Thread::idle_loop(); // Force a call to base class idle_loop() - - // In the helpful master concept, a master can help only a sub-tree of its - // split point and because everything is finished here, it's not possible - // for the master to be booked. - assert(!searching); - assert(!activePosition); - - // We have returned from the idle loop, which means that all threads are - // finished. Note that decreasing splitPointsSize must be done under lock - // protection to avoid a race with Thread::can_join(). - spinlock.acquire(); - - searching = true; - --splitPointsSize; - activeSplitPoint = sp.parentSplitPoint; - activePosition = &pos; - - spinlock.release(); - - // Split point data cannot be changed now, so no need to lock protect - pos.set_nodes_searched(pos.nodes_searched() + sp.nodes); - *bestMove = sp.bestMove; - *bestValue = sp.bestValue; -} - - // TimerThread::idle_loop() is where the timer thread waits Resolution milliseconds // and then calls check_time(). When not searching, thread sleeps until it's woken up. @@ -233,12 +109,31 @@ void TimerThread::idle_loop() { lk.unlock(); - if (run) + if (!exit && run) check_time(); } } +// Thread::idle_loop() is where the thread is parked when it has no work to do + +void Thread::idle_loop() { + + while (!exit) + { + std::unique_lock lk(mutex); + + while (!searching && !exit) + sleepCondition.wait(lk); + + lk.unlock(); + + if (!exit && searching) + search(); + } +} + + // 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. @@ -259,20 +154,12 @@ void MainThread::idle_loop() { lk.unlock(); if (!exit) - { - searching = true; - - Search::think(); - - assert(searching); - - searching = false; - } + think(); } } -// MainThread::join() waits for main thread to finish the search +// MainThread::join() waits for main thread to finish thinking void MainThread::join() { @@ -317,7 +204,6 @@ void ThreadPool::exit() { void ThreadPool::read_uci_options() { - minimumSplitDepth = Options["Min Split Depth"] * ONE_PLY; size_t requested = Options["Threads"]; assert(requested > 0); @@ -333,16 +219,14 @@ void ThreadPool::read_uci_options() { } -// ThreadPool::available_slave() tries to find an idle thread which is available -// to join SplitPoint 'sp'. +// ThreadPool::nodes_searched() returns the number of nodes searched -Thread* ThreadPool::available_slave(const SplitPoint* sp) const { +int64_t ThreadPool::nodes_searched() { - for (Thread* th : *this) - if (th->can_join(sp)) - return th; - - return nullptr; + int64_t nodes = 0; + for (Thread *th : *this) + nodes += th->rootPos.nodes_searched(); + return nodes; } @@ -356,8 +240,8 @@ void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits, Signals.stopOnPonderhit = Signals.firstRootMove = false; Signals.stop = Signals.failedLowAtRoot = false; - RootMoves.clear(); - RootPos = pos; + main()->rootMoves.clear(); + main()->rootPos = pos; Limits = limits; if (states.get()) // If we don't set a new position, preserve current state { @@ -368,7 +252,7 @@ void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits, for (const auto& m : MoveList(pos)) if ( limits.searchmoves.empty() || std::count(limits.searchmoves.begin(), limits.searchmoves.end(), m)) - RootMoves.push_back(RootMove(m)); + main()->rootMoves.push_back(RootMove(m)); main()->thinking = true; main()->notify_one(); // Wake up main thread: 'thinking' must be already set diff --git a/src/thread.h b/src/thread.h index e880b01c..97ed219a 100644 --- a/src/thread.h +++ b/src/thread.h @@ -37,53 +37,6 @@ struct Thread; const size_t MAX_THREADS = 128; -const size_t MAX_SPLITPOINTS_PER_THREAD = 8; -const size_t MAX_SLAVES_PER_SPLITPOINT = 4; - -class Spinlock { - - std::atomic_int lock; - -public: - Spinlock() { lock = 1; } // Init here to workaround a bug with MSVC 2013 - void acquire() { - while (lock.fetch_sub(1, std::memory_order_acquire) != 1) - while (lock.load(std::memory_order_relaxed) <= 0) - std::this_thread::yield(); // Be nice to hyperthreading - } - void release() { lock.store(1, std::memory_order_release); } -}; - - -/// SplitPoint struct stores information shared by the threads searching in -/// parallel below the same split point. It is populated at splitting time. - -struct SplitPoint { - - // Const data after split point has been setup - const Position* pos; - Search::Stack* ss; - Thread* master; - Depth depth; - Value beta; - int nodeType; - bool cutNode; - - // Const pointers to shared data - MovePicker* movePicker; - SplitPoint* parentSplitPoint; - - // Shared variable data - Spinlock spinlock; - std::bitset slavesMask; - volatile bool allSlavesSearching; - volatile uint64_t nodes; - volatile Value alpha; - volatile Value bestValue; - volatile Move bestMove; - volatile int moveCount; - volatile bool cutoff; -}; /// ThreadBase struct is the base of the hierarchy from where we derive all the @@ -94,10 +47,10 @@ struct ThreadBase : public std::thread { virtual ~ThreadBase() = default; virtual void idle_loop() = 0; void notify_one(); - void wait_for(volatile const bool& b); + void wait(volatile const bool& b); + void wait_while(volatile const bool& b); Mutex mutex; - Spinlock spinlock; ConditionVariable sleepCondition; volatile bool exit = false; }; @@ -112,22 +65,21 @@ struct Thread : public ThreadBase { Thread(); virtual void idle_loop(); - bool cutoff_occurred() const; - bool can_join(const SplitPoint* sp) const; + void search(bool isMainThread = false); - void split(Position& pos, Search::Stack* ss, Value alpha, Value beta, Value* bestValue, Move* bestMove, - Depth depth, int moveCount, MovePicker* movePicker, int nodeType, bool cutNode); - - SplitPoint splitPoints[MAX_SPLITPOINTS_PER_THREAD]; Pawns::Table pawnsTable; Material::Table materialTable; Endgames endgames; - Position* activePosition; - size_t idx; + size_t idx, PVIdx; int maxPly; - SplitPoint* volatile activeSplitPoint; - volatile size_t splitPointsSize; volatile bool searching; + + Position rootPos; + Search::RootMoveVector rootMoves; + Search::Stack stack[MAX_PLY+4]; + HistoryStats History; + MovesStats Countermoves; + Depth depth; }; @@ -137,6 +89,7 @@ struct Thread : public ThreadBase { struct MainThread : public Thread { virtual void idle_loop(); void join(); + void think(); volatile bool thinking = true; // Avoid a race with start_thinking() }; @@ -161,10 +114,8 @@ struct ThreadPool : public std::vector { MainThread* main() { return static_cast(at(0)); } void read_uci_options(); - Thread* available_slave(const SplitPoint* sp) const; void start_thinking(const Position&, const Search::LimitsType&, Search::StateStackPtr&); - - Depth minimumSplitDepth; + int64_t nodes_searched(); TimerThread* timer; }; diff --git a/src/timeman.cpp b/src/timeman.cpp index 7a5db255..3a4e157f 100644 --- a/src/timeman.cpp +++ b/src/timeman.cpp @@ -80,7 +80,7 @@ namespace { /// inc > 0 && movestogo == 0 means: x basetime + z increment /// inc > 0 && movestogo != 0 means: x moves in y minutes + z increment -void TimeManagement::init(Search::LimitsType& limits, Color us, int ply, TimePoint now) +void TimeManagement::init(Search::LimitsType& limits, Color us, int ply) { int minThinkingTime = Options["Minimum Thinking Time"]; int moveOverhead = Options["Move Overhead"]; @@ -102,7 +102,7 @@ void TimeManagement::init(Search::LimitsType& limits, Color us, int ply, TimePoi limits.npmsec = npmsec; } - start = now; + startTime = limits.startTime; unstablePvFactor = 1; optimumTime = maximumTime = std::max(limits.time[us], minThinkingTime); diff --git a/src/timeman.h b/src/timeman.h index c5390bef..b6eb3485 100644 --- a/src/timeman.h +++ b/src/timeman.h @@ -22,22 +22,23 @@ #include "misc.h" #include "search.h" +#include "thread.h" /// The TimeManagement class computes the optimal time to think depending on /// the maximum available time, the game move number and other parameters. class TimeManagement { public: - void init(Search::LimitsType& limits, Color us, int ply, TimePoint now); + void init(Search::LimitsType& limits, Color us, int ply); void pv_instability(double bestMoveChanges) { unstablePvFactor = 1 + bestMoveChanges; } int available() const { return int(optimumTime * unstablePvFactor * 0.76); } int maximum() const { return maximumTime; } - int elapsed() const { return int(Search::Limits.npmsec ? Search::RootPos.nodes_searched() : now() - start); } + int elapsed() const { return int(Search::Limits.npmsec ? Threads.nodes_searched() : now() - startTime); } int64_t availableNodes; // When in 'nodes as time' mode private: - TimePoint start; + TimePoint startTime; int optimumTime; int maximumTime; double unstablePvFactor; diff --git a/src/uci.cpp b/src/uci.cpp index 4e56542a..c5dbafae 100644 --- a/src/uci.cpp +++ b/src/uci.cpp @@ -112,6 +112,8 @@ namespace { Search::LimitsType limits; string token; + limits.startTime = now(); // As early as possible! + while (is >> token) if (token == "searchmoves") while (is >> token)