Complexities of Performance Prediction for Bandwidth-Limited Loop Kernels on Multi-Core Architectures

The balance metric is a simple approach to estimate the performance of bandwidth-limited loop kernels. However, applying the method to modern multicore architectures yields unsatisfactory results. This paper analyzes the influence of cache hierarchy design on performance predictions for bandwidth-limited loop kernels on current mainstream processors. We present a diagnostic model with improved predictive power, correcting the limitations of the simple balance metric. The importance of code execution overhead even in bandwidth-bound situations is emphasized.