Swap compression: resurrecting old ideas

The performance of memory-intensive applications tends to be poor due to th e high overhead added by the swapping mechanism. The same problem may be fo und in highly-loaded multi-programming systems where all running applicatio ns have to use the swap space in order to be able to execute at the same ti me. In this paper, we present a solution to these problems. The idea consis ts of compressing the swapped pages and keeping them in a swap cache whenev er possible. The idea of a compressed swap cache was proposed a few years ago, but it di d not achieve the expected results due to hardware limitations. As processo rs are much faster and the performance gap between processors and disk is a lso much bigger, me believe that now it is the right time to revisit this i dea. In this paper, we present a new implementation of the compressed cache , plus some enhancements that significantly improve the performance of the swapping mechanism. Copyright (C) 2000 John Wiley & Sons, Ltd.