X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Ftt.cpp;h=9f0bc4ba63091919a123fad9a2185f5f8e1e4fa6;hp=f283d0c6d71c21881d84a8f448cfbb2b537a461e;hb=2af2c67650c4ac2531e6ab2753830f91c0999876;hpb=d8f683760c9eb6d2c4714ec83e717dd2143de55c

diff --git a/src/tt.cpp b/src/tt.cpp
index f283d0c6..9f0bc4ba 100644
--- a/src/tt.cpp
+++ b/src/tt.cpp
@@ -2,7 +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) 2015-2017 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2018 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
@@ -20,9 +20,12 @@
 
 #include <cstring>   // For std::memset
 #include <iostream>
+#include <thread>
 
 #include "bitboard.h"
+#include "misc.h"
 #include "tt.h"
+#include "uci.h"
 
 TranspositionTable TT; // Our global transposition table
 
@@ -33,15 +36,10 @@ TranspositionTable TT; // Our global transposition table
 
 void TranspositionTable::resize(size_t mbSize) {
 
-  size_t newClusterCount = size_t(1) << msb((mbSize * 1024 * 1024) / sizeof(Cluster));
-
-  if (newClusterCount == clusterCount)
-      return;
-
-  clusterCount = newClusterCount;
+  clusterCount = mbSize * 1024 * 1024 / sizeof(Cluster);
 
   free(mem);
-  mem = calloc(clusterCount * sizeof(Cluster) + CacheLineSize - 1, 1);
+  mem = malloc(clusterCount * sizeof(Cluster) + CacheLineSize - 1);
 
   if (!mem)
   {
@@ -51,18 +49,35 @@ void TranspositionTable::resize(size_t mbSize) {
   }
 
   table = (Cluster*)((uintptr_t(mem) + CacheLineSize - 1) & ~(CacheLineSize - 1));
+  clear();
 }
 
 
 /// TranspositionTable::clear() overwrites the entire transposition table
 /// with zeros. It is called whenever the table is resized, or when the
 /// user asks the program to clear the table (from the UCI interface).
+/// It starts as many threads as allowed by the Threads option.
 
 void TranspositionTable::clear() {
 
-  std::memset(table, 0, clusterCount * sizeof(Cluster));
-}
+  const size_t stride = clusterCount / Options["Threads"];
+  std::vector<std::thread> threads;
+  for (size_t idx = 0; idx < Options["Threads"]; idx++)
+  {
+      const size_t start =  stride * idx,
+                   len =    idx != Options["Threads"] - 1 ?
+                            stride :
+                            clusterCount - start;
+      threads.push_back(std::thread([this, idx, start, len]() {
+          if (Options["Threads"] >= 8)
+              WinProcGroup::bindThisThread(idx);
+          std::memset(&table[start], 0, len * sizeof(Cluster));
+      }));
+  }
 
+  for (std::thread& th: threads)
+      th.join();
+}
 
 /// TranspositionTable::probe() looks up the current position in the transposition
 /// table. It returns true and a pointer to the TTEntry if the position is found.