Priority Page Replacement Policy to Improve Cache Memory Efficiency

Replacement policies play a crucial part in different aspects of today’s high performance computing environments such as Web Caching, Cache Management in Microprocessors, Page Management in Operating Systems, Replication strategies in Distributed Information Systems and etc. Because of the vital role of replacement policies in the systems, there have been lots of work and proposed algorithms to overcome the problem of performance gap existing between processor and memory. Most of these policies are the enhancement of the Least-Recently-Used (LRU) and Least-Frequently-Used (LFU) schemes. Although most of the proposed schemes could solve the defects of the LRU and LFU, however, they have lots of overhead and are difficult to implement. The most advantage of LRU and LFU is due to their simple implementation. This article proposes an adaptive replacement algorithm which has low overhead on system and is easy to implement. This model is named Priority Replacement Policy (PRP) which is based on ranking of the pages in the cache according to three parameters. Whenever a miss occurs, a page with the lowest rank point is selected to be substituted by the new desired page. An advantage of this technique is due to its similarities to the algorithms LRU, LFU and a newly developed algorithm known as the Weighting Replacement Policy (WRP). The proposed method solves the problems associated with WRP and in cases like loops in which LRU fails, it will switch to LFU. Simulations show that this algorithm performs better than WRP, LRU and LFU.

Keywords:

Operating system , Memory management , Page replacement algorithms , Cache memory