Computation of Cold-Start Miss Ratios

Cold-start miss ratios are miss ratios that are measured with an initially empty first-level store. The values obtained depend on C, the first-level storage capacity, and on T, the number of references. These miss ratios, measured for various values of T, are useful in evaluating the effect of task switching on cache miss ratios when the cache capacity is C. For a particular (C, T) a practical method is described for obtaining the average of the w - T + 1 cold-start miss ratios measured on the substrings of length T of a reference string of length w. The method, which applies to set-associative LRU, can be used to find average cold-start miss ratios for a matrix of (C, T) pairs in one pass. In the general case, the computation time increases approximately logarithmically in the number of (C, T) pairs as the number of pairs is increased.