The Cost of Address Translation

TL;DR

This paper introduces the VAT model to accurately measure the computational cost of address translation in modern memory hierarchies, aligning theoretical predictions with actual performance measurements.

Contribution

The paper proposes the VAT model, a new framework that incorporates address translation costs into algorithm analysis, improving accuracy over traditional models.

Findings

VAT model predictions match empirical measurements

Address translation significantly impacts algorithm performance

Analysis of cache-oblivious algorithms in VAT model

Abstract

Modern computers are not random access machines (RAMs). They have a memory hierarchy, multiple cores, and virtual memory. In this paper, we address the computational cost of address translation in virtual memory. Starting point for our work is the observation that the analysis of some simple algorithms (random scan of an array, binary search, heapsort) in either the RAM model or the EM model (external memory model) does not correctly predict growth rates of actual running times. We propose the VAT model (virtual address translation) to account for the cost of address translations and analyze the algorithms mentioned above and others in the model. The predictions agree with the measurements. We also analyze the VAT-cost of cache-oblivious algorithms.