Cache architecture using way id to reduce near memory traffic in a two-level memory system

Abstract

One embodiment provides an apparatus. The apparatus includes last level cache circuitry and cache management circuitry. The last level cache circuitry stores cache blocks that at least partially include a subset of cache blocks stored by near memory circuitry. The near memory circuitry is configured in an n-way set associative format that references the cache blocks stored by the near memory circuitry using set identifiers and way identifiers. The cache management circuitry stores way identifiers for the cache blocks of the near memory circuitry within the cache blocks in the last level cache circuitry. Storing way identifiers in the cache blocks of the last level cache enables the cache management circuitry or memory controller circuitry to write back a cache block without reading tags in one or more ways of the near memory circuitry.