X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=948f526cce836613e4e88fa80db9533ab9613c8e;hp=f374b462f8a0169be2a28399cb313975b653af56;hb=13d4df95cd4c56c0e730328648de54d9ed8bd81e;hpb=13c11f40480ec97316bd4da3a53787cc871037ea diff --git a/src/search.cpp b/src/search.cpp index f374b462..948f526c 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -90,6 +90,45 @@ namespace { Move best = MOVE_NONE; }; + struct FastMove { + FastMove() { clear(); } + + inline void clear() { + expectedPosKey = 0; + pv3[0] = pv3[1] = pv3[2] = MOVE_NONE; + stableCnt = 0; + } + + void update(Position& pos) { + // Keep track how many times in a row the PV stays stable 3 ply deep. + const std::vector& RMpv = RootMoves[0].pv; + if (RMpv.size() >= 3) + { + if (pv3[2] == RMpv[2]) + stableCnt++; + else + stableCnt = 0, pv3[2] = RMpv[2]; + + if (!expectedPosKey || pv3[0] != RMpv[0] || pv3[1] != RMpv[1]) + { + pv3[0] = RMpv[0], pv3[1] = RMpv[1]; + StateInfo st[2]; + pos.do_move(RMpv[0], st[0], pos.gives_check(RMpv[0], CheckInfo(pos))); + pos.do_move(RMpv[1], st[1], pos.gives_check(RMpv[1], CheckInfo(pos))); + expectedPosKey = pos.key(); + pos.undo_move(RMpv[1]); + pos.undo_move(RMpv[0]); + } + } + else + clear(); + } + + Key expectedPosKey; + Move pv3[3]; + int stableCnt; + } FM; + size_t PVIdx; TimeManager TimeMgr; double BestMoveChanges; @@ -281,6 +320,10 @@ namespace { Depth depth; Value bestValue, alpha, beta, delta; + // Init fastMove if the previous search generated a candidate and we now got the predicted position. + const Move fastMove = (FM.expectedPosKey == pos.key()) ? FM.pv3[2] : MOVE_NONE; + FM.clear(); + std::memset(ss-2, 0, 5 * sizeof(Stack)); depth = DEPTH_ZERO; @@ -405,27 +448,43 @@ namespace { Signals.stop = true; // Do we have time for the next iteration? Can we stop searching now? - if (Limits.use_time_management() && !Signals.stop && !Signals.stopOnPonderhit) + if (Limits.use_time_management()) { - // Take some extra time if the best move has changed - if (depth > 4 * ONE_PLY && multiPV == 1) - TimeMgr.pv_instability(BestMoveChanges); - - // Stop the search if only one legal move is available or all - // of the available time has been used. - if ( RootMoves.size() == 1 - || now() - SearchTime > TimeMgr.available_time()) + if (!Signals.stop && !Signals.stopOnPonderhit) { - // 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; + // Take some extra time if the best move has changed + if (depth > 4 * ONE_PLY && multiPV == 1) + TimeMgr.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 a fastMove + // from the previous search and just did a fast verification. + if ( RootMoves.size() == 1 + || now() - SearchTime > TimeMgr.available_time() + || ( fastMove == RootMoves[0].pv[0] + && BestMoveChanges < 0.03 + && 10 * (now() - SearchTime) > TimeMgr.available_time())) + { + // 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; + } } + + // Update fast move stats. + FM.update(pos); } } + // Clear any candidate fast move that wasn't completely stable for at least + // the 6 final search iterations. (Independent of actual depth and thus TC.) + // Time condition prevents consecutive fast moves. + if (FM.stableCnt < 6 || now() - SearchTime < TimeMgr.available_time()) + FM.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(), @@ -767,7 +826,7 @@ moves_loop: // When in check and at SpNode search starts from here continue; moveCount = ++splitPoint->moveCount; - splitPoint->mutex.unlock(); + splitPoint->spinlock.release(); } else ++moveCount; @@ -836,7 +895,7 @@ moves_loop: // When in check and at SpNode search starts from here && moveCount >= FutilityMoveCounts[improving][depth]) { if (SpNode) - splitPoint->mutex.lock(); + splitPoint->spinlock.acquire(); continue; } @@ -855,7 +914,7 @@ moves_loop: // When in check and at SpNode search starts from here if (SpNode) { - splitPoint->mutex.lock(); + splitPoint->spinlock.acquire(); if (bestValue > splitPoint->bestValue) splitPoint->bestValue = bestValue; } @@ -867,7 +926,7 @@ moves_loop: // When in check and at SpNode search starts from here if (predictedDepth < 4 * ONE_PLY && pos.see_sign(move) < VALUE_ZERO) { if (SpNode) - splitPoint->mutex.lock(); + splitPoint->spinlock.acquire(); continue; } @@ -967,7 +1026,7 @@ moves_loop: // When in check and at SpNode search starts from here // Step 18. Check for new best move if (SpNode) { - splitPoint->mutex.lock(); + splitPoint->spinlock.acquire(); bestValue = splitPoint->bestValue; alpha = splitPoint->alpha; } @@ -1012,6 +1071,10 @@ moves_loop: // When in check and at SpNode search starts from here if (value > alpha) { + // Clear fast move if unstable. + if (PvNode && pos.key() == FM.expectedPosKey && (move != FM.pv3[2] || moveCount > 1)) + FM.clear(); + bestMove = SpNode ? splitPoint->bestMove = move : move; if (PvNode && !RootNode) // Update pv even in fail-high case @@ -1532,8 +1595,25 @@ void Thread::idle_loop() { assert(!this_sp || (this_sp->master == this && searching)); - while (!exit) + while ( !exit + && !(this_sp && this_sp->slavesMask.none())) { + // If there is nothing to do, sleep. + while( !exit + && !(this_sp && this_sp->slavesMask.none()) + && !searching) + { + if ( !this_sp + && !Threads.main()->thinking) + { + std::unique_lock lk(mutex); + while (!exit && !Threads.main()->thinking) + sleepCondition.wait(lk); + } + else + std::this_thread::yield(); + } + // If this thread has been assigned work, launch a search while (searching) { @@ -1550,7 +1630,7 @@ void Thread::idle_loop() { std::memcpy(ss-2, sp->ss-2, 5 * sizeof(Stack)); ss->splitPoint = sp; - sp->mutex.lock(); + sp->spinlock.acquire(); assert(activePosition == nullptr); @@ -1576,19 +1656,10 @@ void Thread::idle_loop() { sp->allSlavesSearching = false; sp->nodes += pos.nodes_searched(); - // Wake up the master thread so to allow it to return from the idle - // loop in case we are the last slave of the split point. - if (this != sp->master && sp->slavesMask.none()) - { - assert(!sp->master->searching); - - sp->master->notify_one(); - } - // 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->mutex.unlock(); + sp->spinlock.release(); // Try to late join to another split point if none of its slaves has // already finished. @@ -1628,12 +1699,12 @@ void Thread::idle_loop() { sp = bestSp; // Recheck the conditions under lock protection - sp->mutex.lock(); + sp->spinlock.acquire(); if ( sp->allSlavesSearching && sp->slavesMask.count() < MAX_SLAVES_PER_SPLITPOINT) { - mutex.lock(); + spinlock.acquire(); if (can_join(sp)) { @@ -1642,27 +1713,12 @@ void Thread::idle_loop() { searching = true; } - mutex.unlock(); + spinlock.release(); } - sp->mutex.unlock(); + sp->spinlock.release(); } } - - // Avoid races with notify_one() fired from last slave of the split point - std::unique_lock lk(mutex); - - // If we are master and all slaves have finished then exit idle_loop - if (this_sp && this_sp->slavesMask.none()) - { - assert(!searching); - break; - } - - // If we are not searching, wait for a condition to be signaled instead of - // wasting CPU time polling for work. - if (!searching && !exit) - sleepCondition.wait(lk); } } @@ -1711,7 +1767,7 @@ void check_time() { { SplitPoint& sp = th->splitPoints[i]; - sp.mutex.lock(); + sp.spinlock.acquire(); nodes += sp.nodes; @@ -1719,7 +1775,7 @@ void check_time() { if (sp.slavesMask.test(idx) && Threads[idx]->activePosition) nodes += Threads[idx]->activePosition->nodes_searched(); - sp.mutex.unlock(); + sp.spinlock.release(); } if (nodes >= Limits.nodes)