The relative worst order ratio applied to paging
Joan Boyar, Lene M. Favrholdt, Kim Skak Larsen · 2005
Abstract. The relative worst order ratio, a new measure for the quality of on-line algorithms, was recently defined and applied to two bin packing problems. Here, we apply it to the paging problem. Work in progress by various researchers shows that the measure gives interesting results and new separations for bin coloring, scheduling, and seat reservation problems as well. Using the relative worst order ratio, we obtain the following results: We devise a new deterministic paging algorithm, Retrospective-LRU, and show that it performs better than LRU. This is supported by experimental results, but contrasts with the competitive ratio. All deterministic marking algorithms have the same competitive ratio, but here we find that LRU is better than FWF. No deterministic marking algorithm can be significantly better than LRU, but the randomized algorithm MARK is better than LRU. Finally, look-ahead is shown to be a significant advantage, in contrast to the competitive ratio, which does not reflect that look-ahead can be helpful. 1