A low-overhead heterogeneous variable way L2 Cache

Exploiting non-uniform distribution of cache accesses among sets,V-Way cache allows varying ways in sets according to the run-time demands and outperforms conventional set-associative cache in resource utilization.However,the tag array in V-Way cache is expanded,inducing large area and power overhead.Considering that the tag array is under-utilized in V-Way cache,we propose a low-overhead heterogeneous variable way cache,named HV-Way cache.The HV-Way cache adopts a heterogeneous tag array and cut down the capacity of tag ways by sets sharing in the same way.Maintaining tag replacement information in per-set granularity,The HV-Way cache selects the least recently used tag entries for eviction.Experiment results of Cacti and Simics simulators show that the HV-Way cache brings down the latency,area and power overhead greatly at the expense of small performance loss.