Improving Data Cache Performance using Persistence Selective Caching

This paper presents Persistence Selective Caching (PSC), a selective caching scheme that tracks the reusability of L1 data cache (L1D) lines at runtime, and moves lines with sufficient potential for reuse to a low-latency, low-energy assist cache from where subsequent references to them are serviced. The selectivity of PSC is configurable, and can be adjusted to suit the varying memory access characteristics of different applications, unlike existing schemes. By effectively identifying reusable cache lines and storing them in the assist, PSC reduces average memory access time by upto 59% as compared to competing schemes and conventional data caches. Furthermore, by ensuring that only reusable lines are cached by the assist, PSC reduces cache line movements, and thus decreases average energy per access by upto 75% over other assists.