Using Fuzzy Logic to Improve Cache Replacement Decisions

Most researches concerning uniform caching base their replacement decision on just one parameter. This parameter in some cases may not do well because of the workload characteristics. Some others use more than one parameter. In this case, finding the relation between these parameters and how to combine them is another problem. A number of algorithms try to combine their decision parameter with some mathematical equations. But as different workloads have different characteristics, it is not possible to express the parameters relation with an exact mathematical formula. In real world situations, it would often be more realistic to find viable compromises between these parameters. For many problems, it makes sense to partially consider each of them. One especially straightforward method to achieve this is the modeling of these parameters through fuzzy logic. This paper proposes a fuzzy algorithm in which the decision parameters are treated as fuzzy variables. A simulation is also performed and the results are compared with Optimal, LRU and LFU replacement algorithms. The latter two algorithms are the most commonly used algorithms for replacement of cache objects and the first one is a theoretical optimal algorithm. It is concluded that the proposed fuzzy approach is very promising and it has the potential to be considered for future research.