Brief announcement: Writeback-aware caching

Abstract

Motivated by emerging memory technologies and the increasing importance of energy and bandwidth, we study the Writeback-Aware Caching Problem. This problem modifies the caching problem by explicitly accounting for the cost of writing data to memory. In the offline setting with maximum writeback cost ω > 0, we show that the writeback-oblivious optimal policy is only (ω + 1)-competitive for writeback-aware caching, and that writeback-aware caching is NP-complete and Max-SNP hard. In the online setting, we present a deterministic online replacement policy, called Writeback-Aware Landlord and show that it obtains the optimal competitive ratio. Finally, we perform an experimental study on real-world traces which shows that Writeback-Aware Landlord outperforms state-of-the-art cache replacement policies when writebacks are costly.