A Cache Fill and Migration Policy for STT-RAM-Based Multi-Level Hybrid Cache in 3D CMPs

Abstract

Recently, in 3D Chip-Multiprocessors (CMPs), a hybrid cache architecture of SRAM and Non-Volatile Memory (NVM) is generally used to exploit high density and low leakage power of NVM and a low write overhead of SRAM. The conventional access policy does not consider the hybrid cache and cannot make good use of the characteristics of both NVM and SRAM technology. This paper proposes a Cache Fill and Migration policy (CFM) for multi-level hybrid cache. In CFM, data access was optimized in three aspects: Cache fill, cache eviction, and dirty data migration. The CFM reduces unnecessary cache fill, write operations to NVM, and optimizes the victim cache line selection in cache eviction. The results of experiments show that the CFM can improve performance by 24.1% and reduce power consumption by 18% when compared to conventional writeback access policy. This paper proposes a cache fill and migration policy (CFM) for multi-level hybrid cache in 3D CMPs. The CFM optimizes data access in three aspects: Cache fill, cache eviction and data migration compared to the conventional writeback access policy. Firstly, the CFM can effectively reduce the unnecessary cache fill and the write operations to the NVM if a cache fill is required. Secondly, the CFM optimizes the victim cache line selection in cache eviction to reduce the data migration overhead of the dirty victim. Finally, the CFM analyzes the migration cost in multi-level hybrid cache architecture and proposes two migration principles to minimize the migration cost. These two migration principles are suitable in dark silicon era, in which case some open cache banks become closed and some closed cache banks become open (we call this cache architecture dynamically reconfiguration). The results show that in multi-level hybrid cache architecture, the CFM can achieve performance improvement and power saving effectively.The rest of the paper is organized as follows. Section 2 analyzes the problems in conventional writeback access policy in hybrid cache. Section 3 presents the proposed cache fill and migration policy. Section 4 shows the experimental results and finally the conclusion is given in Section 5.

Analysis and Application of Practical Ability of Multimedia Technology in Art Education

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