Cache-miss-initiated prefetch in mobile environments

Prefetching has been widely used to improve system performance in mobile environments. Since prefetching also consumes system resources such as bandwidth and power, it is important to consider the system overhead when designing a prefetching scheme. This paper proposes a cache-miss-initiated prefetch (CMIP) scheme to address this issue. The CMIP scheme relies on two prefetch sets: the always-prefetch set and the miss-prefetch set. The always-prefetch set consists of data that should always be prefetched if possible. The miss-prefetch set consists of data that are closely related to the cache-missed data item. When a cache miss happens, instead of sending an uplink request to ask for the cache-missed data item only, the client also requests for the data items which are within the miss-prefetch set. This reduces not only future cache misses but also the number of uplink requests. Note that the client can ask for several data items in one uplink request with little additional cost. We propose novel algorithms to mine the association rules and use them to construct the two prefetch sets. Simulation results show that our CMIP scheme can greatly improve the system performance in terms of improved cache hit ratio, reduced uplink requests, and negligible additional traffic.