openmw-tes3mp

Commit Graph

Author	SHA1	Message	Date
elsid	1e2aae8095	Use stable sort+unique to collect RefIDs for ESMStore records counting The idea is to avoid std::map lookup for each CellRef. Instead generate a sequence of added and removed RefNums into a vector then order them by RefNum using a stable sort that preserves relative order of elements with the same RefNum. RefIDs are stored in a different vector to avoid std::string move ctor calls when swapping elements while sorting. Reversed iteration over added and removed RefNums for each unique RefNum is an equivalent to what map-based algorithm produces. The main benefit from sorting a vector is a data locality that means less cache misses for each access. Reduces ESMStore::countRecords perf cycles by 25%.	4 years ago

Author

SHA1

Message

Date

elsid

1e2aae8095

Use stable sort+unique to collect RefIDs for ESMStore records counting

The idea is to avoid std::map lookup for each CellRef. Instead generate a
sequence of added and removed RefNums into a vector then order them by RefNum
using a stable sort that preserves relative order of elements with the same
RefNum. RefIDs are stored in a different vector to avoid std::string move ctor
calls when swapping elements while sorting. Reversed iteration over added and
removed RefNums for each unique RefNum is an equivalent to what map-based
algorithm produces. The main benefit from sorting a vector is a data locality
that means less cache misses for each access. Reduces ESMStore::countRecords
perf cycles by 25%.

1 Commits (00997fa7327293db6075d47d18bd36516537ba44)