Trace-based Automatic Padding for Locality Improvement with Correlative Data Visualization Interface

Abstract

The efficient use of the cache hierarchy of an execution platform often has a major impact on the performance of an application. It is often difficult for the application programmer or the compiler to determine a suitable memory layout for the application data, since the interactions between the memory accesses cannot be fully anticipated before the program execution. This paper introduces an approach to improve the cache efficiency by dynamically padding memory allocations by a post-compilation tool. Data structures like histograms are used to evaluate cache simulations of memory traces of the application considered and to compute optimized pad sets. These can then be used for later runs of the application with different data sets. The accumulated representation of the references' memory accesses additionally offers a visualization interface to the algorithm-specific memory access pattern of each reference captured. As implied above, the advantage of the method is that it also allows for an improvement of the cache usage of binary only applications for which no source code is available. Post optimization cache behavior analyses as well as run-time measurements show that the cache hit rates of the runtime-modified applications are considerably increased by applying the generated pad set.