🦈 IMP: Prefetching Transposition Table Entries

--- STC --- ELO | 12.71 +- 7.53 (95%) SPRT | 10.0+0.10s Threads=1 Hash=16MB LLR | 2.97 (-2.94, 2.94) [0.00, 5.00] GAMES | N: 4760 W: 1474 L: 1300 D: 1986 --- LTC --- ELO | 14.66 +- 7.98 (95%) SPRT | 60.0+0.60s Threads=1 Hash=256MB LLR | 3.00 (-2.94, 2.94) [0.00, 5.00] GAMES | N: 3888 W: 1121 L: 957 D: 1810 Bench: 8291587
TheBlackPlague · May 31, 2023 · df04152 · df04152
1 parent 338e909
commit df04152
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Showing 2 changed files with 14 additions and 6 deletions.
diff --git a/src/Backend/TranspositionTable.h b/src/Backend/TranspositionTable.h
@@ -10,6 +10,8 @@
 #include <algorithm>
 #include <execution>
 
+#include <xmmintrin.h>
+
 #include "Type/Zobrist.h"
 
 #include "../External/fastrange.h"
@@ -53,6 +55,11 @@ namespace StockDory
                 return Internal[fastrange64(hash, Count)];
             }
 
+            inline void Prefetch(const ZobristHash hash) const
+            {
+                _mm_prefetch(reinterpret_cast<const char*>(&Internal[fastrange64(hash, Count)]), _MM_HINT_T0);
+            }
+
             [[nodiscard]]
             inline uint64_t Size() const
             {

diff --git a/src/Engine/Search.h b/src/Engine/Search.h
@@ -455,15 +455,12 @@ namespace StockDory
                     if (seeEvaluation > beta) return seeEvaluation;
                     //endregion
 
-                    constexpr MoveType MT = NNUE | ZOBRIST;
-
-                    PreviousState state = Board.Move<MT>(move.From(), move.To(), move.Promotion());
-                    Nodes++;
+                    const PreviousState state = EngineMove<false>(move);
 
                     int32_t evaluation =
                             -Q<OColor, Pv>(ply + 1, depth - 1, -beta, -alpha);
 
-                    Board.UndoMove<MT>(state, move.From(), move.To());
+                    EngineUndoMove<false>(state, move);
 
                     //region Handle Evaluation
                     if (evaluation <= bestEvaluation) continue;
@@ -525,7 +522,11 @@ namespace StockDory
                 const PreviousState state = Board.Move<MT>(move.From(), move.To(), move.Promotion());
                 Nodes++;
 
-                if (UpdateHistory) Repetition.Push(Board.Zobrist());
+                const ZobristHash hash = Board.Zobrist();
+
+                TTable.Prefetch(hash);
+
+                if (UpdateHistory) Repetition.Push(hash);
 
                 return state;
             }