Cache Memory Architecture for Leakage Energy Reduction

Recently, energy dissipation by microprocessors is getting larger, which leads to a serious problem in terms of allowable temperature and performance improvement for future microprocessors. Cache memory is effective in bridging a growing speed gap between a processor and relatively slow external main memory, and has increased in its size. Almost all of today's commercial processors, not only high- performance microprocessors but embedded ones, have on- chip cache memories. However, energy dissipation in the cache memory will approach or exceed 50% of the increasing total energy dissipation by processors. An important point to note is that, in the near future, static (leakage) energy will dominate the total energy consumption in deep sub-micron processes. This paper describes cache memory architecture, especially for on-chip multiprocessors, that achieves efficient reduction of leakage energy in cache memories by exploiting gated-Vdd control, software self- invalidation for LI cache, and dynamic data compression for L2 cache. The simulation results show that our techniques can reduce a substantial amount of leakage energy without large performance degradation.