Efficient computation of optimal space-time performance curves for memory hierarchies

Abstract

The problem of determining the best possible space-time performance for a given program executing in a two-level memory hierarchy for a given access time ratio is known to be computationally expensive. That one often wishes to determine such optimal performance across a broad range of access time ratios changes an expensive computational task into one which is often not feasible. We present a technique by which, given an acceptable error bound, a piecewise linear approximation to the actual space-time vs. access time ratio curve may be efficiently derived. That approximation is shown to deviate from the actual curve by no more than specified by the error bound. Such curves are useful in performance evaluation studies for memory management schemes in which the allocation of real memory is dynamically varied.