초록/요약

In this article, we analyze Android applications' memory reference behaviors, and observe that smartphone memory accesses are different from traditional computer systems with respect to the following five aspects: 1) A limited number of hot pages account for a majority of memory writes, and these hot pages have similar logical addresses regardless of application types; 2) The identities of these hot pages are shared library, linker, and stack regions; 3) The memory access behaviors of hot pages do not change significantly as time progresses even after applications finish their launching; 4) The skewness of memory write accesses in Android is extremely stronger than that of desktop systems; 5) In predicting re-reference likelihood of hot pages, temporal locality is better than reference frequency. Based on these observations, we present a new smartphone memory management scheme for DRAM-NVM hybrid memory. Adopting NVM is effective in power-saving of smartphones, but NVM has weaknesses in write operations. Thus, we aim to identify write-intensive pages and place them on DRAM. Unlike previous studies, we prevent migration of pages between DRAM and NVM, which eliminates unnecessary NVM write traffic that accounts for 32-42% of total write traffic. By judiciously managing the admission of hot pages in DRAM, our scheme reduces the write traffic to NVM by 42% on average without performance degradations.