Algorithm for Using Cache Misses Using a Shadow Cache Directory
Original Publication Date: 1989-May-01
Included in the Prior Art Database: 2005-Jan-27
Current system cache directories conform to the size of the cache data array. They, therefore, can maintain no historical information related to the recentness of the existence of a line in the cache. By doubling the directory size, that is, by maintaining a directory on twice as many lines as the cache can hold, a means is established for assessing the dynamic behavior of the lines as they reenter the cache. There are several ways to use the additional information derived from a hit in the shadow directory. 1. Such lines can be flagged for special treatment by the cache replacement algorithm. 2.