SOPA: Selecting the Optimal Policy Adaptively for a cache system

With the development of storage technique, new caching policies are continuously being introduced, which makes it increasingly important for cache systems to select the optimal caching policy dynamically under varying workloads. This paper proposes SOPA, a mechanism to adaptively select the optimal policy and perform policy switching. First, SOPA encapsulates the functions of a caching policy into a module, and enables online policy switching by policy reconstruction. Second, SOPA selects the optimal policy dynamically by collecting and analyzing access traces, and reduces the decision-making cost by asynchronous decision. The simulation evaluation showed that no single caching policy could perform well under all of the different workloads, but SOPA could select the appropriate policy for each workload. The real-system evaluation showed that SOPA could reduce the average response time by up to 20.3% compared with LRU and up to 11.9% compared with ARC.