Energy Reduction Strategy In Hybrid Memory Subsystem

PhaseChangeMemory(PCMforshort)isanewlyemergenttechnologyformemo-rystorage. Recentresearchesconsideritasanext-generationmainmemory. Comparedwith traditional Dynamic Random Access Memory(DRAM), it has better performancein higher storage density, non-volatility and higher anti-radiation. Yet it still has someinherent disadvantages. It costs more time and energy in write operation and it haslimited write endurance. Based on these observations, More researches paid attentionto integrating DRAM with PCM into a hybrid main memory system. Previous workfocused on reducing PCM writes and expanding PCM lifespan. Few of them took en-ergy reduction in hybrid memory into consideration. In fact the DRAM’s idle energyconsumption is well beyond PCM’s and accounts for large ratio in total energy. In thispaper, we mainly focus on reducing hybrid system’s energy consumption. We proposea simple but efective energy state transition strategy and further develop two page mi-gration strategies. We implement our design based on cycle-accurate CPU simulationand compare its performance with other memory architecture. The experiment resultsshow that our design is better in terms of metric Energy and Energy×Delay2.