X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Ftt.h;h=84a4b9faec4701fb4b69b9c246cd01bf0952f267;hp=a983805b19afdc5ae207097c4a2539862d0a4740;hb=328098d027e7c35625acbb28e42732137c02d0c1;hpb=93195555ed230df1d29933de6236d6847ae88310;ds=sidebyside diff --git a/src/tt.h b/src/tt.h index a983805b..84a4b9fa 100644 --- a/src/tt.h +++ b/src/tt.h @@ -76,8 +76,9 @@ private: /// A TranspositionTable consists of a power of 2 number of clusters and each /// cluster consists of ClusterSize number of TTEntry. Each non-empty entry /// contains information of exactly one position. The size of a cluster should -/// not be bigger than a cache line size. In case it is less, it should be padded -/// to guarantee always aligned accesses. +/// divide the size of a cache line size, to ensure that clusters never cross +/// cache lines. This ensures best cache performance, as the cacheline is +/// prefetched, as soon as possible. class TranspositionTable { @@ -86,10 +87,10 @@ class TranspositionTable { struct Cluster { TTEntry entry[ClusterSize]; - char padding[2]; // Align to the cache line size + char padding[2]; // Align to a divisor of the cache line size }; - static_assert(sizeof(Cluster) == CacheLineSize / 2, "Cluster size incorrect"); + static_assert(CacheLineSize % sizeof(Cluster) == 0, "Cluster size incorrect"); public: ~TranspositionTable() { free(mem); }