Code Motion for Migration Minimization in STT-RAM Based Hybrid Cache

Hybrid caches consisting of both STT-RAM and SRAM have been proposed recently for energy efficiency. To explore the advantages of hybrid cache, most work on hybrid caches employs migration based strategies to dynamically move write-intensive data from STT-RAM to SRAM. Migrations require additional read and write operations for data movement and may lead to significant overheads. To address this issue,this paper proposes a compilation method, Migration-aware Code Motion (MCM), to improve the energy efficiency and performance of STT-RAM based hybrid cache. This method is designed to change the data access patterns in memory blocks such that the migration overhead is reduced without any hardware modification. The experimental results show that the proposed method can reduce the number of migrations by 10.6%,reduce the dynamic energy by 6.2%, and reduce the total latency by 5.3% on average.