Code placement techniques for cache miss rate reduction

Abstract

In the design of embedded systems with cache memories, it is important to minimize the cache miss rates to reduce power consumption of the systems as well as improve the performance. In this article, we propose two code placement methods (a simplified method and a refined one) to reduce miss rates of instruction caches. We first define a simplified code placement problem without an attempt to minimize the code size. The problem is formulated as an integer linear programming (ILP) problem, by which an optimal placement can be found. Experimental results show that the simplified method reduces cache misses by an average of 30% (max. 77%). However, the code size obtained by the simplified method tends to be large, which inevitably leads to a larger memory size. In order to overcome this limitation, we further propose a refined code placement method in which the code size provided by the system designers must be satisfied. The effectiveness of the refined method is also demonstrated. © 1997 ACM.